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Bryan Cardella

Bryan Cardella

Origins of Life

Slide Duration:

Table of Contents

I. Introduction to Biology
Scientific Method

26m 23s

Intro
0:00
Origins of the Scientific Method
0:04
Steps of the Scientific Method
3:08
Observe
3:21
Ask a Question
4:00
State a Hypothesis
4:08
Obtain Data (Experiment)
4:25
Interpret Data (Result)
5:01
Analysis (Form Conclusions)
5:38
Scientific Method in Action
6:16
Control vs. Experimental Groups
7:24
Independent vs. Dependent Variables
9:51
Other Factors Remain Constant
11:03
Scientific Method Example
13:58
Scientific Method Illustration
17:35
More on the Scientific Method
22:16
Experiments Need to Duplicate
24:07
Peer Review
24:46
New Discoveries
25:23
Molecular Basis of Biology

46m 22s

Intro
0:00
Building Blocks of Matter
0:06
Matter
0:32
Mass
1:10
Atom
1:48
Ions
5:50
Bonds
8:29
Molecules
9:55
Ionic Bonds
9:57
Covalent Bonds
11:10
Water
12:30
Organic Compounds
17:48
Carbohydrates
18:04
Lipids
19:43
Proteins
20:42
Nucleic Acids
22:21
Carbohydrates
22:54
Sugars
22:56
Functions
23:42
Molecular Representation Formula
26:34
Examples
27:15
Lipids
28:44
Fats
28:46
Triglycerides
29:04
Functions
32:10
Steroids
33:43
Saturated Fats
34:18
Unsaturated Fats
36:08
Proteins
37:26
Amino Acids
37:58
3D Structure Relates to Their Function
38:54
Structural Proteins vs Globular Proteins
39:41
Functions
40:41
Nucleic Acids
42:53
Nucleotides
43:04
DNA and RNA
44:34
Functions
45:07
II. Cells: Structure & Function
Cells: Parts & Characteristics

1h 12m 12s

Intro
0:00
Microscopes
0:06
Anton Van Leeuwenhoek
0:58
Robert Hooke
1:36
Matthias Schleiden
2:52
Theodor Schwann
3:19
Electron Microscopes
4:16
SEM and TEM
4:54
The Cell Theory
5:21
3 Tenets
5:24
All Organisms Are Composed of One Or More Cells
5:46
The Cell is the Basic Unit of Structure and Function for Organisms
6:01
All Cells Comes from Preexisting Cells
6:34
The Characteristics of Life
8:09
Display Organization
8:18
Grow and Develop
9:12
Reproduce
9:33
Respond to Stimuli
9:55
Maintain Homeostasis
10:23
Can Evolve
11:37
Prokaryote vs. Eukaryote
11:53
Prokaryote
12:13
Eukaryote
14:00
Cell Parts
16:53
Plasma Membrane
18:27
Cell Membrane
18:29
Protective and Regulatory
18:52
Semi-Permeable
19:18
Polar Heads with Non-Polar Tails
20:52
Proteins are Imbedded in the Layer
22:46
Nucleus
25:53
Contains the DNA in Nuclear Envelope
26:31
Brain on the Cell
28:12
Nucleolus
28:26
Ribosome
29:02
Protein Synthesis Sites
29:25
Made of RNA and Protein
29:29
Found in Cytoplasm
30:24
Endoplasmic Reticulum
31:49
Adjacent to Nucleus
32:07
Site of Numerous Chemical Reactions
32:37
Rough
32:56
Smooth
33:48
Golgi Apparatus
34:54
Flattened Membranous Sacs
35:10
Function
35:45
Cell Parts Review
37:06
Mitochondrion
39:45
Mitochondria
39:50
Membrane-Bound Organelles
40:07
Outer Double Membrane
40:57
Produces Energy-Storing Molecules
41:46
Chloroplast
43:45
In Plant Cells
43:47
Membrane-Bound Organelles with Their Own DNA and Ribosomes
44:20
Thylakoids
44:59
Produces Sugars Through Photosynthesis
45:46
Vacuoles/ Vesicles
46:44
Vacuoles
47:03
Vesicles
47:59
Lysosome
50:21
Membranous Sac for Breakdown of Molecules
50:34
Contains Digestive Enzymes
51:55
Centrioles
53:15
Found in Pairs
53:18
Made of Cylindrical Ring of Microtubules
53:22
Contained Within Centrosomes
53:51
Functions as Anchors for Spindle Apparatus in Cell Division
54:06
Spindle Apparatus
55:27
Cytoskeleton
55:55
Forms Framework or Scaffolding for Cell
56:05
Provides Network of Protein Fibers for Travel
56:24
Made of Microtubules, Microfilaments, and Intermediate Filaments
57:18
Cilia
59:21
Cilium
59:27
Made of Ring of Microtubules
1:00:00
How They Move
1:00:35
Flagellum
1:02:42
Flagella
1:02:51
Long, Tail-Like Projection from a Cell
1:02:59
How They Move
1:03:27
Cell Wall
1:05:21
Outside of Plasma Membrane
1:05:25
Extra Protection and Rigidity for a Cell
1:05:52
In Plants
1:07:19
In Bacteria
1:07:25
In Fungi
1:07:41
Cytoplasm
1:08:07
Fluid-Filled Region of a Cell
1:08:24
Sight for Majority of the Cellular Reactions
1:08:47
Cytosol
1:09:29
Animal Cell vs. Plant Cell
1:09:10
Cellular Transport

32m 1s

Intro
0:00
Passive Transport
0:05
Movement of Substances in Nature Without the Input of Energy
0:14
High Concentration to Low Concentration
0:36
Opposite of Active Transport
1:41
No Net Movement
3:20
Diffusion
3:55
Definition of Diffusion
3:58
Examples
4:07
Facilitated Diffusion
7:32
Definition of Facilitated Diffusion
7:49
Osmosis
9:34
Definition of Osmosis
9:42
Examples
10:50
Concentration Gradient
15:55
Definition of Concentration Gradient
16:01
Relative Concentrations
17:32
Hypertonic Solution
17:48
Hypotonic Solution
20:07
Isotonic Solution
21:27
Active Transport
22:49
Movement of Molecules Across a Membrane with the Use Energy
22:51
Example
23:30
Endocytosis
25:53
Wrapping Around of Part of the Plasma
26:13
Examples
26:26
Phagocytosis
28:54
Pinocytosis
29:02
Exocytosis
29:40
Releasing Material From Inside of a Cell
29:43
Opposite of Endocytosis
29:50
Cellular Energy, Part I

52m 11s

Intro
0:00
Energy Facts
0:05
Law of Thermodynamics
0:16
Potential Energy
2:27
Kinetic Energy
2:50
Chemical Energy
3:01
Mechanical Energy
3:20
Solar Energy
3:41
ATP Structure
4:07
Adenosine Triphosphate
4:12
Common Energy Source
4:25
ATP Function
6:13
How It Works
7:18
What It Is Used For
7:43
GTP
9:36
ATP Cycle
10:35
ATP Formation
10:49
ATP Use
12:12
Enzyme Basics
13:51
Catalysts
13:59
Protein-Based
14:39
Reaction Occurs
14:51
Enzyme Structure
19:14
Active Site
19:23
Induced Fit
20:15
Enzyme Function
21:22
What Enzymes Help With
21:31
Inhibition
21:57
Ideal Environment to Function Properly
22:57
Enzyme Examples
25:26
Amylase
25:34
Catalase
26:03
DNA Polymerase
26:21
Rubisco
27:06
Photosynthesis
28:19
Process To Make Glucose
28:27
Photoauthotrophs
28:34
Endergonic
30:08
Reaction
30:22
Chloroplast Structure
31:55
Photosynthesis Factories Found in Plant Cells
32:26
Thylakoids
32:29
Stroma
33:18
Chloroplast Micrograph
34:14
Photosystems
34:46
Thylakoid Membranes Are Filled with These Reaction Centers
34:58
Photosystem II and Photosystem I
35:47
Light Reactions
37:09
Light-Dependent Reactions
37:24
Step 1
37:35
Step 2
38:31
Step 3
39:33
Step 4
40:33
Step 5
40:51
Step 6
41:30
Dark Reactions
43:15
Light-Independent Reactions or Calvin Cycle
43:19
Calvin Cycle
44:54
Cellular Energy, Part II

40m 50s

Intro
0:00
Aerobic Respiration
0:05
Process of Breaking Down Carbohydrates to Make ATP
0:45
Glycolysis
1:44
Krebs Cycle
1:48
Oxidative Phosphorylation
2:06
Produces About 36 ATP
2:24
Glycolysis
3:35
Breakdown of Sugar Into Pyruvates
4:16
Occurs in the Cytoplasm
4:30
Krebs Cycle
11:40
Citric Acid Cycle
11:42
Acetyl-CoA
12:04
How Pyruvate Gets Modified into acetyl-CoA
12:35
Oxidative Phosphorylation
22:45
Anaerobic Respiration
29:44
Lactic Acid Fermentation
31:06
Alcohol Fermentation
31:51
Produces Only the ATP From Glycolysis
32:09
Aerobic Respiration vs. Photosynthesis
36:43
Cell Division

1h 9m 12s

Intro
0:00
Purposes of Cell Division
0:05
Growth and Development
0:17
Tissue Regeneration
0:51
Reproduction
1:51
Cell Size Limitations
4:01
Surface-to-Volume Ratio
5:33
Genome-to-Volume Ratio
10:29
The Cell Cycle
12:20
Interphase
13:23
Mitosis
14:08
Cytokinesis
14:21
Chromosome Structure
16:08
Sister Chromatids
19:00
Centromere
19:22
Chromatin
19:48
Interphase
21:38
Growth Phase #1
22:25
Synthesis of DNA
23:09
Growth Phase #2
23:52
Mitosis
25:13
4 Main Phases
25:21
Purpose of Mitosis
26:40
Prophase
28:46
Condense DNA
28:56
Nuclear Envelope Breaks Down
29:44
Nucleolus Disappears
30:04
Centriole Pairs Move to Poles
30:31
Spindle Apparatus Forms
31:22
Metaphase
32:36
Chromosomes Line Up Along Equator
32:43
Metaphase Plate
33:29
Anaphase
34:21
Sister Chromatids are Separated
34:26
Sister Chromatids Migrate Towards Poles
36:59
Telophase
37:17
Chromatids Become De-Condensed
37:31
Nuclear Envelope Reforms
37:59
Nucleoli Reappears
38:22
Spindle Apparatus Breaks Down
38:32
Cytokinesis
39:01
In Animal Cells
39:31
In Plant Cells
40:38
Cancer in Relation to Mitosis
41:59
Cancer Can Occur in Multicellular Organism
42:31
Particular Genes Control the Pace
43:11
Benign vs. Malignant
45:13
Metastasis
46:45
Natural Killer Cells
47:33
Meiosis
48:17
Produces 4 Cells with Half the Number of Chromosomes
49:02
Produces Genetically Unique Daughter Cells
51:56
Meiosis I
52:39
Prophase I
53:14
Metaphase I
57:44
Anaphase I
59:10
Telophase I
1:00:00
Meiosis II
1:01:04
Prophase II
1:01:08
Metaphase II
1:01:32
Anaphase II
1:02:08
Telophase II
1:02:43
Meiosis Overview
1:03:39
Products of Meiosis
1:06:00
Gametes
1:06:10
Sperm and Egg
1:06:17
Different Process for Spermatogenesis vs. Oogenesis
1:06:27
III. From DNA to Protein
DNA

51m 42s

Intro
0:00
DNA: Its Role and Characteristics
0:05
Deoxyribonucleic Acid
0:17
Double Helix
1:28
Nucleotides
2:31
Anti-parallel
2:46
Self-Replicating
3:36
Codons, Genes, Chromosomes
3:56
DNA: The Discovery
5:13
DNA First Mentioned
5:50
Bacterial Transformation with DNA
6:32
Base Pairing Rule
8:06
DNA is Hereditary Material
9:44
X-Ray Crystallography Images
10:46
DNA Structure
11:49
Nucleotides
12:54
The Double Helix
16:34
Hydrogen Bonding
16:40
Backbone of Phosphates and Sugars
19:25
Strands are Anti-Parallel
19:37
Nitrogenous Bases
20:52
Purines
21:38
Pyrimidines
22:46
DNA Replication Overview
24:33
DNA Must Duplicate Every Time a Cell is Going to Divide
24:34
Semiconservative Replication
24:49
How Does it Occur?
27:34
DNA Replication Steps
28:39
DNA Helicase Unzips Double Stranded DNA
28:49
RNA Primer is Laid Down
29:10
DNA Polymerase Attaches Complementary Bases in Continuous Manner
30:07
DNA Polymerase Attaches Complementary Bases in Fragments
31:06
DNA Polymerase Replaces RNA Primers
31:22
DNA Ligase Connects Fragments Together
31:44
DNA Replication Illustration
32:25
'Junk' DNA
45:02
Only 2% of the Human Genome Codes for Protein
45:11
What Does Junk DNA Mean to Us?
46:52
DNA Technology Uses These Sequences
49:20
RNA

51m 59s

Intro
0:00
The Central Dogma
0:04
Transcription
0:57
Translation
1:11
RNA: Its Role and Characteristics
2:02
Ribonucleic Acid
2:06
How It Is Different From DNA
2:59
DNA and RNA Differences
5:00
Types of RNA
6:01
Messenger RNA
6:15
Ribosomal RNA
6:49
Transfer RNA
7:52
Others
8:54
Transcription
9:26
Process in Which RNA is Made From a Gene in DNA
9:30
How It's Done
9:55
Summary of Steps
10:35
Transcription Steps
11:54
Initiation
11:57
Elongation
15:57
Termination
18:10
RNA Processing
21:35
Pre-mRNA
21:37
Modifications
21:53
Translation
27:01
Process in Which mRNA Binds with a Ribosome and tRNA and rRNA Assist
27:03
Summary of Steps
28:39
Translation the mRNA Code
28:59
Every Codon in mRNA Gets Translated to an Amino Acid
29:14
Chart Providing the Resulting Translation
29:19
Translation Steps
32:20
Initiation
32:23
Elongation
35:31
Termination
38:43
Mutations
40:22
Code in DNA is Subject to Change
41:00
Why Mutations Happen
41:23
Point Mutation
43:16
Insertion / Deletion
47:58
Duplications
50:03
Genetics, Part I

1h 15m 17s

Intro
0:00
Gregor Mendel
0:05
Father of Genetics
0:39
Experimented with Crossing Peas
1:02
Discovered Consistent Patterns
2:37
Mendel's Laws of Genetics
3:10
Law of Segregation
3:20
Law of Independent Assortment
5:07
Genetics Vocabulary #1
6:28
Gene
6:42
Allele
7:18
Homozygous
8:25
Heterozygous
9:39
Genotype
10:15
Phenotype
11:01
Hybrid
11:53
Pure Breeding
12:28
Generation Vocabulary
13:03
Parental Generation
13:25
1st Filial
13:58
2nd Filial
14:06
Punnett Squares
15:07
Monohybrid Cross
18:52
Mating Pure-Breeding Peas in the P Generation
19:09
F1 Cross
21:31
Dihybrid Cross Introduction
23:42
Traced Inheritance of 2 Genes in Pea Plants
23:50
Dihybrid Cross Example
26:07
Phenotypic Ratio
31:34
Incomplete Dominance
32:02
Blended Inheritance
32:27
Example
32:35
Epistasis
35:05
Occurs When a Gene Has the Ability to Completely Cancel Out the Expression of Another Gene
35:10
Example
35:30
Multiple Alleles
40:12
More Than Two Forms of Alleles
40:23
Example
41:06
Polygenic Inheritance
46:50
Many Traits Get Phenotype From the Inheritance of Numerous Genes
46:58
Example
47:26
Test Cross
51:53
In Cases of Complete Dominance
52:03
Test Cross Demonstrates Which Genotype They Have
52:52
Sex-Linked Traits
53:56
Autosomes
54:21
Sex Chromosomes
54:57
Genetic Disorders
59:31
Autosomal Recessive
1:00:00
Autosomal Dominant
1:06:17
Sex-Linked Recessive
1:09:19
Sex-Linked Dominant
1:13:41
Genetics, Part II

49m 57s

Intro
0:00
Karotyping
0:04
Process to Check Chromosomes for Abnormal Characteristics
0:08
Done with Cells From a Fetus
0:58
Amniocentesis
1:02
Normal Karotype
2:43
Abnormal Karotype
4:20
Nondisjunction
5:14
Failure of Chromosomes to Properly Separate During Meiosis
5:16
Nondisjunction
5:45
Typically Causes Chromosomal Disorders Upon Fertilization
6:33
Chromosomal Disorders
10:52
Autosome Disorders
11:01
Sex Chromosome Disorders
14:06
Pedigrees
20:29
Visual Depiction of an Inheritance Pattern for One Gene in a Family's History
20:30
Symbols
20:46
Trait Being Traced is Depicted by Coloring in the Individual
21:58
Pedigree Example #1
22:26
Pedigree Example #2
25:02
Pedigree Example #3
27:23
Environmental Impact
30:24
Gene Expression Is Often Influenced by Environment
30:25
Twin Studies
30:35
Examples
31:45
Genetic Engineering
36:03
Genetic Transformation
36:17
Restriction Enzymes
39:09
Recombinant DNA
40:37
Gene Cloning
41:58
Polymerase Chain Reaction
43:13
Gel Electrophoresis
44:37
Transgenic Organisms
48:03
IV. History of Life
Evolution

1h 47m 19s

Intro
0:00
The Scientists Behind the Theory
0:04
Fossil Study and Catastrophism
0:18
Gradualism
1:13
Population Growth
2:00
Early Evolution Thought
2:37
Natural Selection As a Sound Theory
8:05
Darwin's Voyage
8:59
Galapagos Islands Stop
9:15
Theory of Natural Selection
11:24
Natural Selection Summary
12:37
Populations have Enormous Reproductive Potential
13:45
Population Sizes Tend to Remain Relatively Stable
14:55
Resources Are Limited
16:51
Individuals Compete for Survival
17:16
There is Much Variation Among Individuals in a Population
17:36
Much Variation is Heritable
18:06
Only the Most Fit Individuals Survive
18:27
Evolution Occurs As Advantageous Traits Accumulate
19:23
Evidence for Evolution
19:47
Molecular Biology
19:53
Homologous Structures
22:55
Analogous Structures
26:20
Embryology
29:36
Paleontology
34:54
Patterns of Evolution
40:14
Divergent Evolution
40:37
Convergent Evolution
43:15
Co-Evolution
46:07
Gradualism vs. Punctuated Equilibrium
49:56
Modes of Selection
52:25
Directional Selection
54:40
Disruptive Selection
56:38
Stabilizing Selection
58:07
Artificial Selection
59:56
Sexual Selection
1:02:13
More on Sexual Selection
1:03:00
Sexual Dimorphism
1:03:26
Examples
1:04:50
Notes on Natural Selection
1:09:41
Phenotype
1:10:01
Only Heritable Traits
1:11:00
Mutations Fuel Natural Selection
11:39
Reproductive Isolation
1:12:00
Temporal Isolation
1:12:59
Behavioral Isolation
1:14:17
Mechanical Isolation
1:15:13
Gametic Isolation
1:16:21
Geographic Isolation
1:16:51
Reproductive Isolation (Post-Zygotic)
1:18:37
Hybrid Sterility
1:18:57
Hybrid Inviability
1:20:08
Hybrid Breakdown
1:20:31
Speciation
1:21:02
Process in Which New Species Forms From an Ancestral Form
1:21:13
Factors That Can Lead to Development of a New Species
1:21:19
Adaptive Radiation
1:24:26
Radiating of Various New Species
1:24:28
Changes in Appearance
1:24:56
Examples
1:24:14
Hardy-Weinberg Theorem
1:27:35
Five Conditions
1:28:15
Equations
1:33:55
Microevolution
1:36:59
Natural Selection
1:37:11
Genetic Drift
1:37:34
Gene Flow
1:40:54
Nonrandom Mating
1:41:06
Clarifications About Evolution
1:41:24
A Single Organism Cannot Evolve
1:41:34
No Single Missing Link with Human Evolution
1:43:01
Humans Did Not Evolve from Chimpanzees
1:46:13
Human Evolution

47m 31s

Intro
0:00
Primates
0:04
Typical Primate Characteristics
1:12
Strepsirrhines
3:26
Haplorhines
4:08
Anthropoids
5:03
New World Monkeys
5:15
Old World Moneys
6:20
Hominoids
6:51
Hominins
7:51
Hominins
8:46
Larger Brains
8:53
Thinner, Flatter Face
9:02
High Manual Dexterity
9:30
Bipedal
9:41
Australopithecines
12:11
Earliest Fossil Evidence for Bipedalism
12:24
Earliest Australopithecines
13:06
Lucy
13:35
The Genus 'Homo'
15:20
Living and Extinct Humans
16:46
Features
16:52
Tool Use
17:09
Homo Habilis
17:38
2.4 - 1.4 mya
18:38
Handy Human
19:19
Found In Africa
19:33
Homo Ergaster
20:11
1.8 - 1.2 mya
20:14
Features
20:25
Found In and Outside of Africa
20:41
Most Likely Hunted
21:03
Homo Erectus
21:32
1.8 - 0.4 mya
22:04
Upright Human
22:49
Found in Africa, Asia, and Europe
22:52
Features
22:57
Used Fire
23:07
Homo Heidelbergensis
23:45
1.3 - 0.2 mya
23:50
Transitional Form
24:22
Features
24:36
Homo Sapiens Neanderthalensis
24:56
0.3 - 0.2 mya
25:23
Neander Valley
25:31
Found in Europe and Asia
21:53
Constructed Complex Structures
27:50
Modern Human and Neanderthal
28:50
Homo Sapiens Sapiens
29:34
195,000 Years Ago - Present
29:37
Humans Most Likely Evolved Once
29:50
Features
30:26
Creative and More Control Over the Environment
30:37
Homo Floresiensis
31:36
18,000 Years Old
31:40
The Hobbit
32:09
Brain and Body Proportions are Similar to Australopithecines
32:16
Human Migration Summary
32:49
Origins of Life

40m 58s

Intro
0:00
Brief History of Earth
0:05
About 4.5 Billion Years Old
0:13
Started Off as a Fiery Ball of Hot Volcanic Activity
1:12
Atmospheric Gas of Early Earth
2:20
Gases Expelled Out of Volcanic Vents
3:10
Building Blocks to Organic Compounds
4:47
Miller-Urey Experiment (1953)
5:41
Stanley Miller and Harold Urey
5:48
Amino Acids Were Found in the Sterile Water Beneath
7:27
Protobionts
8:07
Ancestors of Cells as We Know Them
8:19
Lipid Bubbles with Organic Compounds Inside
8:32
Origin of DNA
12:07
First Cells
12:12
RNA Originally Coded for Protein
12:44
DNA Allows for Retention and a Checking for Errors
12:55
Oxygen Surge
14:57
Photosynthesis Changes Oxygen Gas in Atmosphere
16:36
Cells Absorb Solar Energy with Pigment and Could Make Sugars and Release Oxygen
17:05
Endosymbiotic Theory
18:22
First Eukaryote was Born
19:54
First Proposed by Lynn Margulis
22:43
Multicellular Origins
23:08
Cells That Kept Close Quarters and Stayed Attached Had Safety in Numbers
23:28
Hypothesis
23:45
Cambrian Explosion
26:22
Explosion of Species
27:10
Theory and Snowball Earth
28:24
Timeline of Major Events
32:00
Biogenesis

27m 25s

Intro
0:00
Spontaneous Generation
0:04
Spontaneous Generation
0:14
Pseudoscience
1:45
Individuals Who Sought to Disprove This Theory
2:49
Francesco Redi's Experiment
3:33
17th Century Italian Scientist
3:36
Wanted to Debunk the Theory That Maggots Emerge From Rotting Raw Meat
3:48
Lazzaro Spallanzani's Experiment
6:33
18th Century Italian Scientist
6:36
Wanted to Demonstrate That Microbes Could Be Airborne
6:58
Louis Pasteur's Experiment
9:47
19th Century French Scientist
9:51
Disprove Spontaneous Generation
11:17
Pasteur's Vaccine Discovery
13:47
Motivation to Discover a Way to Immunize People Against Disease
14:00
Cholera Bacteria
14:42
Vaccine Explanation
16:42
Inactive Versions of the Virus are Generated in a Culture
16:47
Antigens Injected Into the Person
17:45
Common Immunizations
22:00
Effectiveness
22:03
No Proof That Vaccines Cause Autism
26:33
V. Diversity of Life
Taxonomy

35m 21s

Intro
0:00
Ancient Classification
0:04
Start of Classification Systems
0:56
How Plants and Animals Were Split Up
2:46
Used in Europe Until 1700s
3:27
Modern Classification
3:52
Carolus Linnaeus
3:58
Taxonomy
5:15
Taxonomic Groups
6:57
Domain
7:14
Kingdom
7:29
Phylum
7:39
Class
7:49
Order
8:02
Family
8:09
Genus
8:25
Species
8:45
Binomial Nomenclature
12:10
Genus Species
12:22
Naming System Rules
12:49
Advantages and Disadvantages to Taxonomy
14:56
Advantages
15:00
Disadvantages
17:53
Domains
20:31
Domain Archaea
21:10
Domain Bacteria
21:19
Domain Eukarya
21:43
Extremophiles
22:48
Kingdoms
25:09
Kingdom Archaebacteria
25:17
Kingdom Eubacteria
25:25
Kingdom Protista
25:52
Kingdom Plantae, Fungi, Animalia
27:18
Cladograms
28:07
Relates Evolution to Phylogeny
28:12
Characteristics Lead to Splitting Off Groups of Organisms
28:20
Viruses

44m 25s

Intro
0:00
Virus Basics
0:04
Non-Living Structures have the Potential to Harm Life on Earth
0:14
Made of Nucleic Acids Wrapped in a Protein Coat
2:15
5 to 300 nm Wide
3:12
Virus Structure
4:29
Icosahedral
4:41
Spherical
5:33
Bacteriophage
6:20
Helical
8:56
How Do They Invade Cells?
11:24
Viruses Can Fool Cells to Let Them In
11:27
Viruses Use the Organelles of the Host
12:29
Viruses are Host Specific
12:57
Viral Cycle
16:18
Lytic Cycle
16:34
Lysogenic Cycle
18:53
Connection Between Lytic/ Lysogenic
23:01
Retroviruses
30:04
Process is Backwards
30:52
Reverse Transcriptase
31:08
Example
31:47
HIV/ AIDS
32:38
Human Immunodeficiency Virus
32:42
Acquired Immunodeficiency Syndrome
36:27
Smallpox: A Brief History
37:06
One of the Most Harmful Viral Diseases in Human History
37:09
History
37:53
Prions
41:32
Infectious Proteins That Damage the Nervous System
41:33
Cause Transmittable Spongiform Encephalopathies
41:51
No Known Cure
43:42
Bacteria

46m 1s

Intro
0:00
Archaebacteria
0:04
Thermophiles
1:10
Halophiles
2:06
Acidophiles
2:29
Methanogens
2:59
Archaea and Bacteria Compared to Eukarya
4:25
Archaea and Eukarya
4:36
Bacteria and Eukarya
5:37
Eubacteria
6:35
Nucleoid Region
7:02
Peptidoglycan
7:21
Binary Fission
8:08
No Membrane-Bound Organelles
8:59
Bacterial Shapes
10:19
Coccus
10:26
Bacillus
12:07
Spirillum
12:44
Bacterial Cell Walls
13:17
Gram Positive
13:47
Gram Negative
15:09
Bacterial Adaptations
16:13
Capsule
16:18
Fimbriae
17:51
Conjugation
18:30
Endospore
21:30
Flagella
23:49
Metabolism
24:36
Benefits of Bacteria
27:28
Mutualism
27:32
Connections to Human Life
30:56
Diseases Caused by Bacteria
35:05
STDs
35:15
Respiratory
36:04
Skin
37:15
Digestive Tract
38:00
Nervous System
38:27
Systemic Diseases
39:09
Antibiotics
40:26
Drugs That Block Protein Synthesis
40:40
Drugs That Block Cell Wall Production
41:07
Increased Bacterial Resistance
41:36
Protists

32m 46s

Intro
0:00
Kingdom Protista Basics
0:04
Unicellular and Multicellular
0:28
Asexual and Sexual
0:48
Water and Land
1:06
Resemble Other Life Forms
1:32
Protist Origin
2:04
Evolutionary Bridge Between Bacteria and Multicellular Eukaryotes
2:06
Protist Ancestors
2:27
Protist Debate
4:18
One Kingdom
4:30
Some Scientists Group Into Separate Kingdoms Based on Genetic Links
4:37
Plant-like Protists
6:03
Photoautotrophs
6:12
Green Algae
6:44
Red Algae
7:12
Brown Algae
7:57
Golden Algae
9:10
Dinoflagellates
9:20
Diatoms
9:41
Euglena
10:17
Euglena Structure
10:39
Ulva Life Cycle
12:08
Fungi-Like Protists
15:39
Heterotrophs That Feed on Decaying Organic Matter
15:41
Found Anywhere with Moisture and Warmth
16:04
Cellular Slime Mold Life Cycle
17:34
Animal-like Protists
21:45
Heterotrophs That Eat Live Cells
21:50
Motile
22:03
Amoeba Life Cycle
25:24
How Protists Impact Humans
29:09
Good
29:16
Bad
32:18
Plants, Part I

54m 22s

Intro
0:00
Kingdom Plantae Characteristics
0:05
Cuticle
0:38
Vascular Bundles
1:18
Stomata
2:51
Alternation of Generations
4:16
Plant Origins
5:58
Common Ancestor with Green Algae
6:03
Appeared on Earth 400 Million Years Ago
7:28
Non-Vascular Plants
8:17
Bryophytes
8:45
Anthoworts
9:12
Hepaticophytes
9:19
Bryophyte (Moss) Life Cycle
9:30
Dominant Gametophyte
9:38
Illustration Explanation
9:58
Seedless Vascular Plants
15:26
Do Not Reproduce With Seeds
15:33
Sori
15:42
Lycophytes
15:54
Pterophytes
16:30
Pterophyte (Fern) Life Cycle
17:05
Dominant Generation
17:08
Produce Motile Sperm
17:17
Seed Plants
23:17
Most Vascular Plants Have Seeds
23:25
Cotyledons
23:43
Gymnosperm vs. Angiosperm
24:50
Divisions
25:48
Coniferophytes (Cone-Bearing Plants)
27:05
Examples
27:07
Evergreen or Deciduous
27:44
Gymnosperms
28:26
Economic Importance
29:28
Conifer Life Cycle
30:10
Dominant Generation
30:13
Cones Contain the Gametophyte
30:25
Illustration Explanation
30:31
Anthophytes (Flowering Plants)
38:01
Every Plant That Has Flowers
38:03
Angiosperms
38:28
Various Life Spans
38:03
Flower Anatomy
40:25
Female Parts
40:54
Male Parts
42:49
Flowering Plant Life Cycle
44:48
Dominant Generation
44:56
Flowers Contain the Gametophyte
45:05
Plants, Part II

44m 40s

Intro
0:00
Plant Cell Varieties
0:05
Parenchyma
0:11
Collenchyma
1:37
Sclerenchyma
2:03
Specialized Tissues
2:56
Plant Tissues
3:17
Meristematic Tissue
3:21
Dermal Tissue
6:46
Vascular Tissues
8:45
Ground Tissue
13:56
Roots
14:24
Root Cap
15:59
Cortex
16:17
Endodermis
17:02
Pericycle
17:42
Taproot
18:11
Fibrous
18:20
Modified
18:49
Stems
19:49
Tuber
21:43
Rhizome
21:58
Runner
22:12
Bulb and Corm
22:49
Leaves
23:06
Photosynthesis
23:09
Leaf Parts
23:32
Gas Exchange
25:55
Transpiration
26:25
Seeds
27:41
Cotyledons
28:42
Seed Coat
29:29
Endosperm
29:37
Embryo
30:10
Radicle
30:27
Epicotyl
31:57
Fruit
33:49
Fleshy Fruits
34:46
Aggregate Fruits
35:17
Multiple Fruits
35:50
Dry Fruits
36:27
Plant Hormones
37:44
Definition or Hormones
37:48
Examples
38:12
Plant Responses
40:42
Tropisms
41:00
Nastic Responses
43:04
Fungi

26m 20s

Intro
0:00
Fungi Basics
0:03
Characteristics
0:09
Closely Related to Kingdom Animalia
2:33
Fungal Structure
2:58
Hypae
3:03
Mycelium
5:00
Spore
5:24
Reproductive Strategies
6:15
Fragmentation
6:23
Budding
6:35
Spore Production
7:03
Zygomycota (Molds)
7:50
Sexual Reproduction
8:04
Dikaryotic
9:47
Stolons
10:32
Rhizoids
10:53
Ascomycota (Sac Fungi)
11:43
Largest Phylum of Fungi on Earth
11:47
Ascus
12:20
Conidia
12:30
Example
12:46
Basidiomycota (Club Fungi)
14:51
Basidium
15:14
Common Structures In These Fungi
15:37
Examples
16:17
Deuteromycota (Imperfect Fungi)
17:25
No Known Sexual Life Cycle
17:31
Penicillin
18:00
Benefits of Fungi
18:51
Mutualism
18:56
Food
21:41
Medicines
22:30
Decomposition
23:08
Fungal Infections
23:38
Athlete's Foot
23:44
Ringworm
24:09
Yeast Infections
24:27
Candidemia
24:56
Aspergillus
25:15
Fungal Meningitis
25:44
Animals, Part I

35m 28s

Intro
0:00
Animal Basics
0:05
Multicellular Eukaryotes
0:12
Motility
0:27
Heterotrophic
0:47
Sexual Reproduction
0:57
Symmetry
1:14
Gut
1:26
Cephalization
1:40
Segmentation
1:53
Sensory Organs
2:09
Reproductive Strategies
3:07
Gonads
3:17
Fertilization
4:01
Asexual
4:53
Animal Development
7:27
Zygote
7:29
Blastula
7:50
Gastrula
9:07
Embryo
12:57
Symmetry
13:17
Radial Symmetry
14:14
Bilateral Symmetry
15:26
Asymmetry
16:34
Body Cavities
17:22
Coelom
17:24
Acoelomates
18:39
Pseudocoelomates
19:15
Coelomates
19:40
Major Animal Phyla
20:47
Phylum Porifera
21:15
Phylum Cnidaria
21:33
Phylum Platyhelmininthes, Nematoda, and Annelida
21:44
Phylum Rotifera
21:56
Phylum Mollusca
22:13
Phylum Arthropoda
22:34
Phylum Echinodermata
22:48
Phylum Chordata
23:18
Phylum Porifera
25:15
Sponges
25:23
Oceanic or Aquatic
26:07
Adults are Sessile
26:26
Structure
27:09
Sexual or Asexual Reproduction
28:31
Phylum Cnidaria
28:49
Sea Jellies, Anemonse, Hydrozoans, and Corals
28:57
Mostly Oceanic
30:42
Body Types
31:32
Cnidocytes
33:06
Nerve Net
34:55
Animals, Part II

48m 42s

Intro
0:00
Phylum Platyhelminthes
0:04
Flatworms
0:14
Acoelomates
0:33
Terrestrial, Oceanic, or Aquatic
0:46
Simple Nervous System
2:46
Reproduction
3:38
Phylum Nematoda
4:20
Unsegmented Roundworms
4:25
Pseudocoelomates
4:34
Terrestrial, Oceanic, or Aquatic
4:53
Full Digestive Tract
5:29
Reproduction
7:07
C. Elegans
7:24
Phylum Annelida
8:11
Segmented Roundworms
8:20
Terrestrial, Oceanic, or Aquatic
8:42
Full Digestive Tract
8:56
Accordion-like Movement
11:26
Simple Nervous System
12:31
Sexual Reproduction
13:40
Class Oligochaeta
14:47
Class Polychaeta
14:56
Class Hirudinea
15:13
Phylum Rotifera
16:11
Pseudocoelomates
16:26
Terrestrial, Aquatic
16:42
Digestive Tract
16:56
Phylum Mollusca
18:55
Snails, Slugs, Clams, Oysters
19:00
Terrestrial, Oceanic, or Aquatic
19:14
Mantle
19:29
Full Digestive Tract with Specialized Organs
21:10
Sexual Reproduction
24:29
Major Classes
24:58
Phylum Arthropoda
28:16
Insects, Arachnids, Crustaceans
28:19
Terrestrial, Oceanic, or Aquatic
28:41
Head, Thorax, Abdomen
28:50
Excretion with Malpighian Tubes
32:48
Arthropod Groups
34:06
Phylum Echinodermata
38:32
Sea Stars, Sea Urchins, Sand Dollars, Sea Cucumbers
38:37
Oceanic or Aquatic
39:36
Water Vascular System
39:43
Full Digestive Tract
40:38
Sexual Reproduction
42:01
Phylum Chordata
42:16
All Vertebrates
42:22
Terrestrial, Oceanic, or Aquatic
42:40
Main Body Parts
42:49
Mostly in Subphylum Vertebrata
44:54
Examples
45:14
Animals, Part III

35m 45s

Intro
0:00
Characteristics of Subphylum Vertebrata
0:04
Vertebral Column
0:16
Neural Crest
0:38
Internal Organs
1:24
Fish Characteristics
2:05
Oceanic or Aquatic
2:16
Locomotion with Paired Fins
3:15
Gills
4:18
Fertilization
8:14
Movement
8:30
Fish Classes
8:58
Jawless Fishes
9:06
Cartilaginous Fishes
10:07
Bony Fishes
10:46
Amphibian Characteristics
12:22
Tetrapods
12:29
Moist Skin
14:22
Circulation
14:39
Nictitating Membrane
16:36
Tympanic Membrane
16:56
External Fertilization is Typical
17:34
Amphibian Orders
18:20
Order Anura
18:27
Order Caudata
19:15
Order Gymnophiona
19:59
Reptile Characteristics
20:31
Dry, Scaly Skin
20:37
Lungs for Gas Exchange
22:00
Terrestrial, Oceanic, Aquatic
22:12
Ectothermic
23:07
Internal Fertilization
24:13
Reptile Orders
26:28
Order Squamata
26:33
Order Crocodilia
27:32
Order Testudinata
27:55
Order Sphenodonta
28:30
Bird Characteristics
28:43
Feathers
29:42
Lightweight Bones
31:33
Lungs with Air Sacs
32:25
Endothermic
33:47
Internal Fertilization
34:03
Bird Orders
34:13
Order Passeriformes
34:29
Order Ciconiiformes
34:46
Order Sphenisciformes
34:55
Order Strigiformes
35:20
Order Struthioniformes
35:25
Order Anseriformes
35:38
Mammals

38m 39s

Intro
0:00
Mammary Glands and Hair
0:04
Class Mammalia Name
0:20
Hair Functions
1:53
Metabolic Characteristics
3:58
Endothermy
4:01
Feeding
4:48
Mammalian Organs
8:43
Respiratory System
8:47
Circulation
9:26
Brain and Senses
10:29
Glands
11:56
Mammalian Reproduction
12:55
Live Birth
13:03
Placental
13:17
Marsupial
14:41
Gestation Periods
16:07
Infraclass Marsupialia
17:42
Australia
17:59
Uterus/ Pouch
18:33
Origins
18:53
Examples
19:24
Order Monotremata
20:21
Egg Layers
20:25
Platypus, Echidna
20:55
Shoulder Area Has a Reptilian Bone Structure
21:07
Order Insectivora
22:21
Insectivores
22:23
Pointy Snouts
22:32
Burrowing
22:53
Examples
23:10
Order Chiroptera
23:32
True Flying Mammalian Order
23:38
Wings
23:59
Feeding
24:21
Examples
25:08
Order Xenarthra
25:14
Edentata
25:18
No Teeth
25:23
Location
25:50
Examples
25:55
Order Rodentia
26:33
40% of Mammalian Species
26:38
2 Pairs of Incisors
26:45
Examples
27:28
Order Lagomorpha
28:06
Herbivores
28:30
Examples
28:41
Order Carnivora
29:19
Teeth
29:36
Examples
29:42
Order Proboscidea
30:37
Largest Living Terrestrial Mammals
30:40
Trunks
30:48
Tusks
31:12
Examples
31:33
Order Sirenia
32:01
Large, Slow Moving Aquatic Mammals
32:15
Flippers
32:26
Herbivores
32:37
Examples
32:42
Order Cetacea
32:46
Large, Mostly Hairless Aquatic Mammals
32:50
Flippers
33:06
Fluke
33:18
Blowhole
33:29
Examples
34:10
Order Artiodactyla
34:30
Even-Toed Hoofed Mammals
34:33
Herbivores
34:37
Sometimes Grouped with Cetaceans
34:52
Examples
35:35
Order Perissodactyla
35:57
Odd-Toed Hoofed Mammals
36:00
Herbivores
36:12
Examples
36:27
Order Primates
36:30
Largest Brain-to-Body Ratio
36:35
Arboreal
37:03
Nails
37:33
Examples
38:29
Animal Behavior

29m 55s

Intro
0:00
Behavior Overview
0:04
Behavior
0:08
Origin of Behavior
0:36
Competitive Advantage
1:26
Innate Behaviors
2:05
Genetically Based
2:07
Instinct
2:13
Fixed Action Pattern
3:31
Learned Behavior
5:13
Habituation
5:26
Classical Conditioning
6:31
Operant Conditioning
7:51
Imprinting
10:17
Learned Behavior That Can Only Occur in a Specific Time Period
10:20
Sensitive Period
10:28
Cognitive Behaviors
11:53
Thinking, Reasoning, and Processing Information
12:02
Examples
12:22
Competitive Behaviors
14:40
Agonistic Behavior
14:46
Dominance Hierarchies
15:23
Territorial Behaviors
16:19
More Types of Behavior
17:05
Foraging Behaviors
17:08
Migratory Behaviors
17:53
Biological Rhythms
19:15
Communication Behaviors
20:37
Pheromones
20:52
Auditory Communication
22:18
Courting and Nurturing Behaviors
23:42
Courting Behaviors
23:45
Nurturing Behaviors
26:04
Cooperative Behaviors
26:47
Benefit All Members of the Group
27:01
Example
27:08
VI. Ecology
Ecology, Part I

1h 7m 26s

Intro
0:00
Ecology Basics
0:05
Ecology
0:18
Biotic vs. Abiotic Factors
1:25
Population
2:23
Community
2:45
Ecosystem
3:04
Biosphere
3:27
Individuals and Survival
4:13
Habitat
4:23
Niche
4:37
Symbiosis
7:07
Obtaining Energy
11:14
Producers
11:24
Consumers
13:31
Food Chain
17:11
Model to Illustrate How Matter Moves Through Organisms in an Ecosystem
17:15
Examples
18:31
Food Web
20:29
Keystone Species
22:55
Three Ecological Pyramids
27:28
Pyramid of Energy
27:38
Pyramid of Numbers
31:39
Pyramid of Biomass
34:09
The Water Cycle
37:24
The Carbon Cycle
40:19
The Nitrogen Cycle
43:34
The Phosphorus Cycle
46:42
Population Growth
49:35
Reproductive Patterns
51:58
Life History Patterns Vary
52:10
r-Selection
53:30
K-Selection
56:55
Density Factors
59:02
Density-Dependent Factors
59:29
Density-Independent Factors
1:02:21
Predator / Prey Relationships
1:03:59
Ecology, Part II

50m 50s

Intro
0:00
Mimicry
0:05
Batesian Mimicry
0:38
Müllerian Mimicry
1:53
Camouflage
3:23
Blend In with Surroundings
3:38
Evade Detection by Predators
3:43
Succession
5:22
Primary Succession
5:40
Secondary Succession
7:44
Biomes
9:31
Terrestrial
10:08
Aquatic / Marine
10:05
Desert
11:20
Annual Rainfall
11:24
Flora
13:35
Fauna
14:15
Tundra
14:49
Annual Rainfall
15:00
Permafrost
15:50
Flora
16:06
Fauna
16:40
Taiga (Boreal Forest)
16:59
Annual Rainfall
17:14
Largest Terrestrial Biome
17:33
Flora
18:37
Fauna
18:49
Temperate Grassland
19:07
Annual Rainfall
19:28
Flora
20:14
Fauna
20:18
Tropical Grassland (Savanna)
20:41
Annual Rainfall
21:01
Flora
21:56
Fauna
22:00
Temperate Deciduous Forest
22:19
Annual Rainfall
23:11
Flora
23:45
Fauna
23:50
Tropical Rain Forest
24:11
Annual Rainfall
24:16
Flora
27:15
Fauna
27:49
Lakes
28:05
Eutrophic
28:21
Oligotrophic
28:29
Zones
29:34
Estuaries
32:56
Area Where Freshwater and Salt Water Meet
33:00
Mangrove Swamps
33:12
Nutrient Traps
33:52
Organisms
34:24
Marine
34:50
Euphotic Zone
35:16
Pelagic Zone
37:11
Abyssal Plain
38:15
Conservation Summary
40:03
Biodiversity
40:33
Habitat Loss
44:06
Pollution
44:55
Climate Change
47:03
Global Warming
47:06
Greenhouse Gases
47:48
Polar Ice Caps
49:01
Weather Patterns
50:00
VII. Laboratory
Laboratory Investigation I: Microscope Lab

24m 51s

Intro
0:00
Light Microscope Parts
0:06
Microscope Use
6:25
Mount the Specimen
6:28
Place Slide on Stage
7:29
Ensure Specimen is Above Light Source
8:11
Lowest Objective Lens Faces Downward
8:34
Focus on the Image
9:36
Adjust the Nosepiece If Needed
9:49
Re-Focus
9:57
Human Skin Layers
10:42
Plants Cells
13:43
Human Lung Tissue
15:20
Euglena
18:26
Plant Stem
20:43
Mold
22:57
Laboratory Investigation II: Egg Lab

11m 26s

Intro
0:00
Egg Lab Introduction
0:06
Purpose
0:09
Materials
0:37
Time
1:24
Day 1
1:28
Day 2
3:59
Day 3
6:05
Analysis
7:50
Osmosis Connection
10:24
Hypertonic
10:36
Hypotonic
10:49
Laboratory Investigation III: Carbon Dioxide Production

14m 34s

Intro
0:00
Carbon Dioxide Introduction
0:06
Purpose
0:09
Materials
0:56
Time
2:39
Part I
2:41
Put Water in Large Beaker
3:09
Exhale Into the Water
3:15
Add a Drop of Phenolphthalein
4:31
Add NaOH
5:33
Record the Amount of Drops
6:10
Part II
6:24
Add HCL
6:39
Exercise for Five Minutes
7:26
Return and Re-Do the Exhaling
7:58
Analysis
9:11
Aerobic Respiration Connection
13:18
As Aerobic Respiration Occurs In Cells, Carbon Dioxide Is Produced
13:21
Increase Output of Carbon Dioxide
13:29
Number of Exhalations Increase
14:17
Laboratory Investigation IV: DNA Extraction Lab

10m 38s

Intro
0:00
DNA Lab Introduction
0:06
Purpose
0:09
Materials
0:45
Time
2:03
Part I
2:06
Pour Sports Drink Into the Small Cup
2:08
When Time Expires, Spit Into the Cup
2:53
Add Cell Lysate Solution
3:21
Let it Sit for a Couple Minutes
4:04
Part II
4:10
Slowly Add Cold Ethanol
4:13
DNA Will Creep Up Into the Ethanol Layer
5:01
Analysis
5:59
DNA Structure Connection
8:49
DNA is Microscopic
8:54
Visible DNA
9:39
Extracted DNA
9:49
Laboratory Investigation V: Onion Root Tip Mitosis Lab

13m 12s

Intro
0:00
Mitosis Lab Introduction
0:06
Purpose
0:09
Materials
0:57
Time
1:42
Part I
1:49
Mount the Slide and Zoom Into the Root Apical Meristem
1:50
Zoom In
3:00
Count the Cells in Each Phase
3:09
Record Your Results
3:52
Microscope View Example
3:58
Part II
6:49
Move to Another Part of the Root Apical Meristem
6:55
Count the Phases in this Second Region
7:02
Analysis
9:07
Mitosis Connection
11:17
Rate of Mitosis Varies from Species to Species
11:21
Mitotic Rate Was Higher Since We Used An Actively Dividing Tissue
12:16
Laboratory Investigation VI: Inheritance Lab

13m 55s

Intro
0:00
Inheritance Lab Introduction
0:05
Purpose
0:09
Materials
0:53
Time
2:00
Explanation
2:03
Basic Procedure
5:03
Analysis
8:00
Inheritance Laws Connection
11:23
Law of Segregation
11:31
Law of Independent Assortment
12:49
Laboratory Investigation VII: Allele Frequencies

14m 11s

Intro
0:00
Allele Frequencies Introduction
0:05
Purpose
0:08
Materials
1:34
Time
2:10
Part I
2:12
Part II
7:05
Analysis
7:51
Evolution Connection
10:45
Meant to Stimulate How a Population's Allele Frequencies Change Over Time
10:47
Particular Phenotypes Selected
11:31
Recessive Allele Keeps Dropping
12:18
Laboratory Investigation VIII: Genetic Transformation

16m 42s

Intro
0:00
Genetic Transformation Introduction
0:06
Purpose
0:09
Materials
0:57
Time
3:31
Set-Up
4:18
Starter Culture with E. Coli Colonies
4:21
Just E. Coli
5:37
Ampicillin with No Plasmid
6:24
Ampicillin with Plasmid
7:11
Ampicillin with Plasmid and Arabinose
7:33
Procedure
8:35
Analysis
13:01
Genetic Transformation Connection
14:59
Easier to Transform Bacteria Than a Multicellular Organism
15:03
Desired Trait Can be Expressed from the Bacteria
15:52
Numerous Applications in Medicine
16:04
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Origins of Life

Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.

  • Intro 0:00
  • Brief History of Earth 0:05
    • About 4.5 Billion Years Old
    • Started Off as a Fiery Ball of Hot Volcanic Activity
  • Atmospheric Gas of Early Earth 2:20
    • Gases Expelled Out of Volcanic Vents
    • Building Blocks to Organic Compounds
  • Miller-Urey Experiment (1953) 5:41
    • Stanley Miller and Harold Urey
    • Amino Acids Were Found in the Sterile Water Beneath
  • Protobionts 8:07
    • Ancestors of Cells as We Know Them
    • Lipid Bubbles with Organic Compounds Inside
  • Origin of DNA 12:07
    • First Cells
    • RNA Originally Coded for Protein
    • DNA Allows for Retention and a Checking for Errors
  • Oxygen Surge 14:57
    • Photosynthesis Changes Oxygen Gas in Atmosphere
    • Cells Absorb Solar Energy with Pigment and Could Make Sugars and Release Oxygen
  • Endosymbiotic Theory 18:22
    • First Eukaryote was Born
    • First Proposed by Lynn Margulis
  • Multicellular Origins 23:08
    • Cells That Kept Close Quarters and Stayed Attached Had Safety in Numbers
    • Hypothesis
  • Cambrian Explosion 26:22
    • Explosion of Species
    • Theory and Snowball Earth
  • Timeline of Major Events 32:00

Transcription: Origins of Life

Hi, welcome back to www.educator.com, this is the lesson on origins of life.0000

First, we are going to talk about where earth came from because that is where life as we know exists.0006

Brief history of earth, it is about 4.5 billion years old, I put a little approximation summation symbol there0012

because depending on what source you look in, what textbook, some may say 4.45 or 4.48, around that time.0018

About 4.5 billion years ago is the age of the earth.0027

Form from a coalescing matter into a spherical form.0032

I would not get into a lot of detail here, you can take an astronomy course, astrophysics course,0035

that can explain more details about that.0041

After the Big Bang, after the universe originated, you have a lot of matter coming together in different ways,0044

forming the galaxies, forming stars, as we know them.0052

For the earth, you just had this, what is natural for matter to do, coming together in a very spherical form.0056

At first, it was not the earth as we know it, it was not this blue planet with lush green life.0064

No, it started off as a fiery ball of hot pot volcanic activity.0070

Its early stages, as far as we know, just all kinds of magma coming up through the surface,0076

just very hot and full of volcanic activity.0084

Volcanic activity still exists today, I do not want you to think that it completely ended.0088

There are always volcanic activity happening in various places on earth.0093

We just do not hear about it all the time.0097

But if you look into it, there is still quite a lot of volcanic activity.0099

Back then, in earth’s early years, eventually you had enough cooling,0103

enough calming down of that frequency volcanic activity to have a crust.0110

There was not a crust at first but eventually the lava is cool enough to create it.0116

Once you have land, once you have something that is a little bit more stable and cooler,0120

you can then have some more steps leading towards life.0125

Like I said magma still exists underneath, plenty of it.0129

Volcanic activity is continuing worldwide.0133

Here is an image of that volcanic activity.0136

Speaking of volcanic activity, all of those eruptions, all of that spewing of gas from the earth's surface created an atmosphere.0142

Because of the earth’s gravitational pull, that contributed to a lot of gases hanging around.0152

We have this atmospheric layer, actually several layers, around the earth’s surface.0158

Compared to the earth itself, in terms of the earth’s diameter, the atmosphere is actually quite thin.0165

I have heard it is described as if you had a globe and you put some lacquer finish on the outside,0170

that is analogous to how thin the atmosphere is to the actual diameter of the earth itself.0176

But, the question is, what kind of gases do we usually have on earth’s surface?0182

The key to knowing about earth’s early gases, what came out of volcanic vents?0189

What came out from those volcanic eruptions?0194

If today, you were to go to where a volcano is actively erupting and you are using tools to measure what levels of0198

what gases do we have coming out from this volcanic activity, here is some of them,0205

not all of them but you would find carbon dioxide, water vapor, nitrogen gas, hydrogen sulfide, methane, plenty of other ones.0211

I did not list them all here, there are actually a few other ones that I list on the next slide,0222

when we talk about Stanley Miller and Harold Urey.0229

This little group of gases here does not support life.0233

The first atmosphere on earth, actually for a while,0239

it would have not been able to support mundane animals that alone, most life forms on earth.0243

It would be toxic levels, none of the gases that support life.0248

Speaking of not supporting life, this is not actually earth’s breakdown of gases.0252

This is what we know as Mars atmosphere.0258

Check it out, almost all the gas is carbon dioxide.0263

You might think that plants can get by.0267

This is too much CO₂ level for a plant.0270

Argon, nitrogen, oxygen, carbon monoxide, carbon dioxide, would be the other ones0274

that you would find on earth's early atmosphere that is by itself, toxic.0278

Gases from this time contain the elements, the building blocks for organic compounds.0286

If you look at what you got here, we got carbon, oxygen, hydrogen, nitrogen, and sulfur.0292

Get some phosphorus in there, few other things, you have got all the building blocks you need to make cells, eventually.0301

Think about it, CH and O, that is in every organic compound or molecule.0308

Nitrogen, you would find in nucleic acids and proteins.0313

Sulfur, you definitely find in a particular amino acid, as well in proteins.0319

Those building blocks are there, just not in the right form, not in the right combinations yet.0324

How do you get from inorganic gases to organic compounds?0329

How do you get from gases that are not the building blocks of life to the building blocks of life?0335

The answer to that question from previous slide is Stanley Miller and Harold Urey’s experiment.0343

The Miller-Urey experiment from 1953, these two scientists demonstrated0348

that you can get organic compounds from inorganic starting materials.0352

Here is how they demonstrated it.0357

They had a setup with gases, these are among them, from early earth, like what we talked about in the previous slide.0359

In a glass container, this little spherical container here, with electrodes attached to it so you could zap them.0366

And that is suppose to replicate lightning.0372

If you imagine having these gases in Earth’ early atmosphere,0375

getting enough water vapor up in the atmosphere, you can get lightning storms.0379

The theory was that, maybe over time, lightning zapping these gases could have made a lot of these elements0384

get mixed up in different combinations because of the electricity.0393

They wanted to demonstrate that it is possible.0397

They have a kind of replication of ocean here with water, heat source.0399

You are going to have that heat source from hydrothermal vents, from vents that heat the water.0405

There is lot of theories about how early cells may have come into being in these like hot pools in the ocean.0414

You have heat here, you get some water vapor coming up in here.0423

You create basically, kind of a little mini atmosphere there with lightning.0427

You got a condenser here, cool water wrapped around this particular tube.0432

That can encourage these gases to end up coming down into the liquid.0437

The interesting thing is after they zap these gases repeatedly, they found what was sterile water here,0443

just water with no organic compounds in it.0449

They found amino acids among other organic compounds.0453

They proved it is possible that if you zap these gases enough,0458

you can get them rearranging in interesting combinations like an amino acid or a simple sugar perhaps.0462

The amazing thing is they proved it, the year it happened in 1953 overshadowed by another very famous discovery,0468

the double helix structure of the DNA from Watson and Crick.0478

But I think that the Miller-Urey demonstration is equally as important.0482

Once you have got all these different organic compounds just floating around the ocean,0489

they demonstrated that they could end up there naturally.0494

How do you get to cells?0498

Protobionts, this is a nickname for the earliest cells, almost like the prototype for what became the cells as we know them today.0500

You can start with lipid bubbles.0511

If lipids could end up in the ocean and they could have because of the Harold Urey demonstration.0513

Imagine having some lipid bubble like this, because think about when you put lipids, like oils,0521

vegetable oil and olive oil in water, like in the ocean.0531

They do not mix very well because of the non polar-polar difference.0534

Lipids are non polar, water is a polar molecule.0538

They do not mix very well.0541

Lipids could have formed these little bubbles.0543

Guess what, the plasma membrane is a very lipidy structure, it is phospholipid bilayer.0545

That is part of what keeps else separate from the external environments.0550

If you have lipid bubbles floating around, maybe they could have encapsulated some molecules.0554

You can imagine having little amino acids in there, I’m exaggerating the sizes of these.0562

It has got amino acids.0572

How did it get from amino acids to proteins?0574

One of the explanations is they have done studies with clay.0577

Clay is a natural substance you can find in various parts of the soil, various parts on earth.0584

Clay is one of those substances that, if you put amino acids in water that has a clay layer,0591

something about the clay actually encourages amino acids to stick together and stay together.0597

It has a catalyst for making those initial peptide bonds between amino acids which is great.0602

If you put amino acids together, without that clay, they might stick together0610

but they will end up breaking apart, not too long thereafter.0615

Clay could have possibly encouraged the formation of some of these first proteins.0619

RNA would be the next step.0624

RNA ends up being a molecule that we know about today that code for an amino acid sequence.0626

If you look at the RNA lesson in this course, you can see that various kinds of RNA help make proteins.0633

They help get those amino acids together in a particular sequence.0640

RNA could have ended up in the cells, something ended up being compatible about sequences of bases matching certain amino acids.0645

The exact mechanism of that is not completely understood.0667

There are various theories that explain how do you get from having a little simple protein sequences in cells0670

to having RNA that can code for them and regenerate them.0676

I do no have all the answers to that.0681

One of the things that need to be connected from here to the next step is, how do you get DNA?0683

Without DNA, you cannot pass on that code effectively to the next generation.0690

You do not retain that code for making these different compounds.0695

No DNA organelles at first, therefore, no evolution.0701

These first cells would have existed, faded away, existed, faded away, almost like a trial and error.0705

It could have happened many times until you get to the point where you can retain that code and pass it on.0712

And then, evolution truly begins.0717

Once you have DNA, once you have proteins that can copy that DNA, that is the key.0720

The origin of DNA, how do we get there?0729

The very first cells that function similarly to what we see today,0732

would have had RNA that actually does code for amino acid sequences, but no DNA yet.0736

To get the DNA, you definitely need that other side, you need that double stranded molecule.0743

Change the sugar a little bit, one of the bases becomes different, if you remember the differences between DNA and RNA.0749

Once RNA can give rise to that double stranded molecule, that can be replicated, it can be passed on to daughter cells.0755

RNA originally coded for protein, as far as we know.0763

There was no retention of that code.0766

By retention, I mean being able to preserve it, and a double stranded molecule is perfect for that.0769

Think about this, here is that point.0775

DNA allows for retention and a checking for errors because of attached compliments.0778

Think about this, if this green and red molecule is your double stranded DNA molecule.0782

The red would be your template strand, this goes back to transcription.0787

Here is that template strand and here are your bases.0797

The yellow, I will do this in black because it is hard to read yellow.0800

Here is your RNA, realize that all of these bases are green but that does not matter for this picture.0805

Think about this, if you can have DNA as a double stranded molecule, making RNA at a moments notice.0814

Just cranking RNA when needed and getting data out to other part of the cells to code for protein.0821

The brilliance of having DNA is, if that part or of this part, any of these nucleotides get damaged, there is a mutation that changes.0826

The brilliance of it is, if this changes, the other side has the appropriate compliment.0838

Since A and T go together and C and G go together as compliments, you know what belongs there.0844

When this gets changed, just look at the other side.0850

If both sides get changed, that would be a terrible mutation if both parts end up being wrong.0853

With sexually reproducing organisms, you can look at the other homologous chromosome and see that0860

what should go there to have normal or wild type DNA that codes for the appropriate to molecules.0866

That is a brilliant thing about DNA and retention of the code.0873

With RNA, if you do not have any DNA in the cell and just RNA that gets damaged,0877

how does a cell know what should belong there to code for the appropriate protein.0882

They would not know.0887

DNA is a great way to retain that code, duplicating both side of the DNA0888

and passing that on is a way that evolution gets kicked started.0892

Oxygen surge, imagine for hundreds of millions of years you have got singled cell beings,0899

some of them would be considered chemoautotrophs.0907

Autotroph meaning that they are self energizing, meaning making their own food but they are not using light.0914

Photoautotroph would be describing plants, moss, algae, various plant like organisms that actually do photosynthesis.0925

Chemoautotrophs is not using light, it is using gases and heat coming from hydrothermal vents to make sugars and lipids, and any other food source.0936

Chemoautotrophs probably existed early on, that relates to archaebacteria, this is way before eukaryotes, by the way.0949

We do not have mitochondria or chloroplasts, or nuclei yet.0958

We would have ribosomes, those are not membrane bound organelles.0963

Those are needed to synthesize proteins.0966

Chemoautotrophs probably would have got the process started.0970

Next up, you can have photoautrophy and eventually heterotrophy comes into play.0973

Once you have supplies of food being made, you can have other cells that end up consuming them from outside of themselves.0980

Heterotrophs like us that eat but not like us because we were talking single celled, ancestors of modern day bacteria here.0988

Anyways, in the first couple of billion years of worlds existence, there was little to no oxygen gas in the atmosphere.0996

Completely toxic, in terms of any modern day animal trying to be successful there.1003

How you get to the point where there is enough oxygen gas?1009

Now, our atmosphere, oxygen gas levels is over 20% of the gas volume, in terms of how much oxygen is there.1012

The dawn of photosynthesis really changed it.1022

Thanks to the ancestors of plants, once cells could absorb solar energy with pigment,1026

such as chlorophyll, they could make sugars and release O₂ as waste.1033

Because oxygen gas is a waste product of photosynthesis.1038

Lots of photosynthesis, for millions of years, would have had the surge of oxygen in the atmosphere.1042

And then, that would pave the way for aerobic respiration.1049

Without a significant amount of oxygen gas in the atmosphere,1054

aerobic respiration would have been evolved as a worthwhile process that actually has benefits.1057

For aerobic respiration to take place, you need oxygen.1064

If the oxygen is not there, this would not have come into play as, this is the way to go,1067

this is how you get a lot of energy by using that oxygen.1071

Having oxygen gas in the atmosphere paves the way for what enables us to survive and the average animal to survive.1075

This image here is chlorophyll B, chlorophyll B is one of the few different types of chlorophyll.1083

Magnesium is a very important element in the formation of chlorophyll.1091

Thanks to this molecule, you can actually absorb solar energy.1095

How do you get to the point where you actually have eukaryotic beings, cells with membrane bound organelles,1104

a nucleus, mitochondria, chloroplasts, ER, golgi, etc, how do you get that?1111

For hundreds of millions of years, there are only prokaryotes,1117

this means before a nucleus, before the kernel meaning that nut looking structure of the nucleus.1121

Prokaryotes for so long before you finally get eukaryotes.1130

How do you get there?1136

There is the endosymbiotic theory, this is also known as endosymbiosis.1138

A symbiosis or a symbiotic relationship in biology is where two organisms have some kind of dependency on each other.1142

A lot of times we talk about that in a positive light, like mutualism or commensalism, has a positive factors to that.1151

Sometimes it is parasitism too, that is another different kind of symbiosis that has a negative for one side of it.1162

Symbiosis is this kind of relationship between two different species.1167

Endosymbiosis is telling us that something is inside.1172

It is a good description because here is what we think happened.1178

At some point, a smaller prokaryote was engulfed by a larger prokaryote.1181

Almost as if it is going to eat it via endocytosis.1187

Endocytosis was brought in the cell transport lesson.1192

Endocytosis is how a cell would swallow up or engulf a very large molecule, like a macromolecule or a smaller cell.1199

In this case, this cell that was engulfed, the smaller prokaryote was not consumed.1209

It stayed inside and allow to benefit for the small one and the large one to happen.1215

The first eukaryote was born by this.1222

Here is a little illustration of what could have happen.1225

The only problem I have with this is, we do not know for certain that1227

this first eukaryote actually had a nucleus yet, it is possible they did.1231

I have heard different theories of where the nucleus could have come from.1238

You could have had an invagination or kind of pinching in of part of the plasma membrane1242

that ended up wrapped around DNA and the nuclide region, to get that first nucleus.1247

There are other theories that actually suggest that, you could have had a cell either devoid of DNA1252

or DNA that did not end up in the nucleus but engulfing a cell inside of it,1261

much smaller cell that actually took the place of the genetic material.1267

There are a lot of different theories about how it could have happened.1271

There is your nucleus with your nucleoli.1275

Anyways, they think that an aerobic bacterium, an ancestor of modern day bacteria1277

that actually did aerobic respiration, like a mitochondrion.1284

The mitochondrion helps to break down sugars with the help of oxygen to make a lot of ATP.1289

This bacterium was doing that on its own.1294

If it ends up inside of it, you can get the ancestor of mitochondria.1297

On the other hand, a cyanobacterium, meaning a bacterium that does photosynthesis,1302

this would be an ancestor of blue green algae, could have come in.1309

If you are wondering, what about these little inner membranes,1313

these could have occurred also by a pinching in of pieces of the bacterial plasma membrane1317

and having these little units that increase the surface area,1323

where you are going to have more reactions pertaining to aerobic respiration and photosynthesis.1326

When this comes in, it also was not consumed.1335

This cell, what you end up getting here, this is after many generations of evolution, of course.1338

What you end up getting here is the ancestor to our plant life because you got mitochondria and1344

you have got chloroplasts, what eventually to become chloroplasts.1350

If we are talking about the ancestor of animal cells, you have the same scenario but1353

without the chloroplasts, you would have mitochondria.1358

Who suggested this?1363

This theory was first proposed in the 1970’s by Lynn Margulis.1365

Great theory and it is definitely a sound theory about how this could have happen.1370

Interesting fact about Lynn Margulis, she was married to Carl Sagan.1376

If you do not know about the great Carl Sagan, I highly suggest looking him up.1381

You got eukaryotic cells in the ocean, floating around, doing their thing, doing photosynthesis,1390

eating molecules from outside of themselves.1396

How do you get to bunches of cells interacting together as one organism?1400

How do you get to multicellularity?1405

For multicellular origin, you could potentially have cells that kept close quarters and stayed attached,1408

safety in numbers and they can begin taking on various roles.1419

Here is one hypothesis, if you have a unicellular flagellated protists,1424

you will hear more about protists in the taxonomy lesson and the lesson on kingdom protista.1429

If you had a single celled eukaryote with a little flagella swimming around in the ocean,1436

you could have a bunch like it that eventually come together as an aggregate, a group together.1442

All of them moving their little tails can move around this little group.1450

It is a safety in numbers kind of thing.1453

They are bigger and better, in the community of flagellated protists swimming around.1457

You could have the unspecialized flagellated cells form a hollow sphere.1463

The hollow sphere, if you are wondering what is the significance of that?1470

That eventually ends up helping to form layers between levels of tissue.1473

When you study about how an early embryological fold happens in animals,1479

that pertains to having various layers inside of the body that is going to develop.1486

When we get into that later on in this course, you can find that out when we discuss about how animal body forms develop.1491

Specialized reproductive cells can form because that is how you end up getting the ability for this group of cells1503

to make more groups of cells that are together as one unit, as one organism.1510

This little area that is kind of colored in sort of a reddish purple.1515

That is the area where these cells start to take on the ability to do meiosis.1520

Because if they all have a certain chromosome number,1527

all it takes is this doing some kind of division that results in that haploid number, that half the number that the other cells have.1529

All it takes is two ½, something would be analogous to sperm and egg, to combine to make a new whole.1538

A new diploid that then would divide to make another group of these.1545

Another step is, if they fold in to make tissues, this is the very kind of basic start to1549

how you get layers of tissue whether it is diploblastic or a triploblastic.1558

You can learn about those later on, when we get to the basics of embryology pertaining to animal body forms.1565

To this could be a really reasonable hypothesis for how you get the original multicellular cells, multicellular organisms rather.1571

The Cambrian explosion, in terms of progression of complex life,1584

we have talked about how you get from inorganic compounds or inorganic molecules to organic compounds,1589

how you get to the first cells, how you get to eukaryotic cells, how you get to multicellular life?1596

In terms of the progression of complex life, they were just a few major steps up until 0.5 billion years ago.1603

Once you get was to 500,000,000 years ago, it is the same as 0.5 billion years, then you get a lot more major steps.1612

It is almost exponential how it got from the beginning of earth up until now,1619

with the amazing diversity of 100,000,000 species or more on earth.1624

During the Cambrian period, an explosion of species occurred.1630

The Cambrian explosion is not an actual boom like dynamite, it is not boom goes the dynamite here.1634

Its boom goes the species explosion.1640

Based on the fossil record, especially places like the Burgess shale, I will give you some examples down at the bottom here about that.1643

There are many other fossil sites but this is one of the more famous ones, where we discovered around 5,000,000 years ago,1656

there all these fossilized early animals, the ancestors of all vertebrates, the ancestors of so much life today,1663

that had some very interesting body forms pertaining to life up until this point.1674

And other body forms that just kind of disappeared, stuff that existed for a little bit, was not successful, did not have descendants.1680

You get some really weird things going on but the Cambrian explosion was such a huge contributor to biodiversity today.1689

How do you get from not much success with biodiversity to all of a sudden lot of species?1698

The theory is that earth was an extremely harsh place to live, just prior to this Cambrian period.1705

They even called it snowball earth.1710

There is enough geologic evidence to suggest that, if you look at earth back then, here is earth on its axis, spinning around.1713

If you look at earth way back then, supposedly, instead of it just having ice up here and a lot of ice down here,1724

you had a lot more ice, a heck of a lot more ice like a really intense cool period for millions upon millions of years, that is snowball earth.1734

There was hardly any area for life, as we know it, to successfully exist.1748

It probably did mostly at the equator region where it was a little bit more tolerable, in terms of temperature.1754

Once this thaws out, once the earth then gradually transitions into a warmer period, it starts to thaw and the snowball melts.1762

And then it is like a sigh of relief for all these organisms that survived, like this is actually much more tolerable.1776

It paved the way for having a spreading out of organisms, greater rate of speciation.1785

Here is a couple of interesting examples from the Burgess shale.1794

This particular animal, freaky worm looking thing, this is one of the many body plans1800

that has been discovered from that Cambrian period, in terms of fossil evidence.1806

This here, very famous fossilized form called a trilobite.1811

Trilobites came to being during this Cambrian period.1819

You can see it looks like it has the segmentation and basic body plan of something like a centipede or millipede.1824

This is one of the earliest arthropods.1833

Arthropods are the phylum of animals that includes all insects, arachnids, crustaceans, and the like.1843

Very early example of this thing that would have been patrolling around the ocean,1853

probably a filter feeder, definitely a sexual reproducing organism.1859

The ancestor of arthropods as we know it.1864

Another weird example is an organism whose genus name has been given is this, hallucigenia.1868

It has been called hallucigenia because the body plan is so weird, the fossilized remnants of this is so weird,1875

it is almost like the viewer is hallucinating like how could this possibly be.1884

The image is something like this.1888

It has these legs coming in out of the bottom.1899

Here is the head end, the tail end, this little spike looking things.1901

As far as we know, this does not have any modern day descendants but it existed about ½ billion years ago.1905

It has fossilized remnants, look it up, if you like.1915

A timeline of major events, specially in the last ½ billion years.1921

Keep in mind that, if we were look at a timeline of earth, I’m just going to briefly show you this.1928

If here is the beginning, this is time zero - about 4½ billion years ago - and here is now.1933

If we were to mark the billions of years, here is a 4½, here is going to back about a billion years, 2 billion years,1944

3 billion years, 4 billion years, 4½, all of these you are going to see here is right in this little chunk, amazingly.1952

That is why I said that the progression of life to the complex that we know it today is very exponential, in the sense of the timing of it.1962

You would have had the first cells existing somewhere way back here.1971

You would have the first eukaryotic cells around this time.1977

It took a heck of a lot longer to finally get to the point where you have multicellularity being successful,1981

vertebrae ancestors as we know them today.1991

Here is about 500,000,000 years ago and that is where we are going to start out.1993

The first important kind of event I want to point out is about 443,000,000 years ago,1998

you have the first vertebrates, as far as we know.2013

Please keep in mind that this is all approximate.2017

Even if you look up these periods of time form the Cambrian, all the way up to the quaternary period,2021

these are just approximates.2028

These periods are contained within eras, you got these major eras.2032

We are now in the Paleozoic era.2036

Eventually, we will get to the Mesozoic where you see more dinosaurs and finally to the Cenozoic, modern era.2040

Eons have the era, eons are very long amounts of time.2046

Periods smaller, contained within them.2052

About almost 500,000,000 years ago, the first vertebrates.2056

About 416,000,000 years ago, this would be land plants.2060

Think about this, before this point in time, we have no evidence of plants on land.2067

For so long we have photosynthesis only happening in the ocean.2074

Today, it still happens mostly in the ocean.2077

Bony fishes is 359,000,000 years ago, I forgot the year in front of that one.2084

I will write it here, 359 you get bony fishes.2091

Before then, you had crabs, cartilaginous fishes, soft bone fishes,2098

or organisms that were swimming around but did not have a skeleton.2104

299,000,000 years ago, amphibians, these are individuals that actually have that dual life2112

meaning born in the water as fishes are, but the ability to come on land for periods of time,2125

as modern day frogs can do and salamanders.2134

You got other amphibians that can be on land for a lot longer.2137

They do not dry out, they are not as dependent on water.2143

About 200,000,000 years ago, you have your first dinosaurs and mammals.2147

Now prior to then, you definitely have reptiles.2163

You definitely have reptiles coming into existence, that is how you get dinosaurs, that is how you get mammals.2166

There actually are transitional fossil forms from reptile to mammal2174

that show you that there was a gradual transition until you finally get, now they are officially mammals separate from reptiles.2179

Dinosaurs and mammals coexisted, we know that know.2188

Dinosaurs definitely had their heyday prior to mammals.2192

Mammals at that time would have be much smaller.2195

Of course dinosaurs had some pretty big ones.2197

The first birds about 145,000,000 years ago.2201

I forgot to write the year here but I told you that is about 145, first birds came from reptiles as well.2207

In an earlier lesson I showed you an image of archaeopteryx, that was a transitional form between reptiles and modern day birds.2224

About 65,000,000 years ago, I’m going to tell you that based on a new story I read recently, this is probably much earlier.2235

I read recently that there were actually fossils of flower imprints found much older than this,2244

closer to more like 100,000,000 years ago.2254

The flower fossil record has been pushed back recently.2260

Based on a textbook that I looked in this morning, the textbook is only two years old,2263

said that about 65,000,000 years the first flowers existed.2270

We would have had plant life giving rise to other plant life via seeds prior to flowers2273

because you do have plants out there like cone bearing plants that make seeds without flowers.2279

Flowers is definitely a big step because once you have flowers, they are pretty and they got that nectar.2285

You are going to have pollinators taking advantage of that and flowering plants are really the most successful plant,2293

in terms of how widespread they are and how many species there are.2299

That is a big step in plant evolution.2303

About 34,000,000 years ago, I want to get tight coming up here.2306

About 34,000,000 years ago, mammalian orders meaning the different groups of mammals,2311

you finally see examples of all of them or most of them.2319

Monkeys at about 23, you finally see monkeys.2324

Apes, 5.3 the fun of this is how tight it gets.2338

This just goes to show that the exponential factor I was explaining before.2344

The funny thing about this whole sequence,2351

this numerical sequence from about 0.5 billion years ago up till now is that, this is not even to scale.2356

Think about this, if this is too much over 5 million years ago, 138 should not be right there,2364

and 66 should not be right there, certainly 1.6 should not be there.2371

Whoever made this chart is jumping at different lengths of time to try to fit this in and2375

make it kind of an even spacing between the periods.2383

Putting all of this on this particular timeline to scale,2388

it would be almost impossible to show all these events right in that little span of time.2393

We are hugging this little area right next to now, present day.2398

5.3 we finally see apes.2404

I will tell you the last two because they are really hard to fit in.2409

Hominins meaning specifically that group that includes home habilis, homo erectus, homo ergaster, etc.,2414

you finally see them appearing right here prior to the quartenary.2423

And then us, 200,000 years ago, and then modern day looking homo sapiens closer to 50 to 30,000 years ago.2428

It is just amazing the dominoes that led from way back when in the Cambrian explosion,2440

all the way up to this incredible diversity of life and drastic speciation that has led to life today, as we know it.2448

Thank you for watching www.educator.com.2457

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