Agenda 1/11/16- Evolution and Diversity

Agenda 1/11/16- Evolution and Diversity
Bellwork- Protein Synthesis and Pedigrees Test Vocabulary (next slide)- due by tomorrow New information: Evolution and Diversity- What is evolution? What is Natural Selection? Activity- Discuss Survival of the Sneakiest questions; video and questions (part 1)

Evolution Vocabulary: max 7 words, in your own words
Adaptation Extinction Natural Selection Punctuated equilibrium Gradualism Vestigial Structure Morphology Fossil Fitness Speciation Gene Pool Genetic Variation Homologous Structure

Essential Questions What is meant by the term evolution?
How does pesticide resistance in mosquitos occur? Why are some bacteria antibiotic-resistant? How can science explain the diversity of life on earth?

Evolution Explains the rich diversity of life on Earth
"Nothing in Biology makes sense except in the light of Evolution." Theodosius Dobzhansky "...evolutionary theory - the most powerful integrating idea in all of biology, and essential for other sciences ranging from astronomy to anthropology" Carl Sagan 1997 (Demon Haunted World p 263.)

The Theory of Evolution
What is a theory? Webster’s Dictionary: the word “evolution” change through time Example: My uncle, Kyle’s, taste in music evolved from Aerosmith and VanHalen to Genesis and Yes in the late 1970’s. Biological Definition: the Theory of Evolution Descent with modification. Change in allele frequencies in a population over time.

Evolution: Main Ideas In everyday language: change through time
Biological definitions: descent with modification change in allele frequency in a population over time Modified Organisms Common Ancestor Common Ancestor

What Is Theoretical about the Darwinian View of Life?
A scientific theory Is broad in scope. Generates new hypotheses. Is supported by a large body of evidence. National Academy of Sciences: Theory - “a well substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses.” Other Theories: Theory of Relativity, Theory of Meteorology, Subatomic Particle Theory, Cell Theory

Evolution Involves every field of biology
Applications of evolutionary biology are transforming medicine, agriculture, biotechnology, and conservation biology Illustrates life’s unity and diversity!

What Is Theoretical about the Darwinian View of Life?
Darwin’s theory of evolution by natural selection integrates diverse areas of biological study and stimulates many new research questions. There is no predetermined path for evolution. The way species look and behave today is a response to some past selection event and/or suite of environmental conditions. Species are playing a constant game of catch up.

Survival of the Sneakiest Cartoon
We’ll read through the cartoon together. Answer the questions ON A SEPARATE PIECE OF PAPER.

Bellwork 1/12/15

Agenda 1/12/16- Evidence for Evolution
Bellwork New information: Finish Natural Selection notes; Evidence for evolution Lab/Activity- Quackers Lab

The Evolution of The Theory of Evolution
Linnaeus (classification) Hutton (gradual geologic change) Lamarck (species can change) Malthus (population limits) Cuvier (fossils, extinction) Lyell (modern geology) Darwin (evolution, nutural selection) Mendel (inheritance) Wallace (evolution, natural selection) 1750 American Revolution French Revolution U.S. Civil War 1800 1850 1900 1795 Hutton proposes his theory of gradualism. 1798 Malthus publishes “Essay on the Principle of Population.” 1809 Lamarck publishes his theory of evolution. 1830 Lyell publishes Principles of Geology. 1831–1836 Darwin travels around the world on HMS Beagle. Darwin begins his notebooks on the origin of species. 1837 Darwin writes his essay on the origin of species. 1844 Wallace sends his theory to Darwin. 1858 The Origin of Species is published. 1859 Mendel publishes inheritance papers. 1865

Darwin Darwin made two major points in his book, On the Origin of Species: The many species of organisms presently inhabiting the Earth are descendants of ancestral species. He proposed a mechanism for the evolutionary process, natural selection. Adaptations that increase survival become more common in the population= evolutionary adaptations The Darwinian revolution challenged the traditional views of a young Earth inhabited by unchanging species.

The Voyage of the Beagle
During his travels on the Beagle, Darwin observed and collected many specimens of South American plants and animals with various adaptations to diverse environments. Galapagos Islands Figure 22.5 England EUROPE NORTH AMERICA Galápagos Islands Darwin in 1840, after his return SOUTH Cape of Good Hope Cape Horn Tierra del Fuego AFRICA HMS Beagle in port AUSTRALIA Tasmania New Zealand PACIFIC OCEAN Andes ATLANTIC

Darwin’s Focus on Adaptation
Darwin began to perceive adaptation to the environment and the origin of new species as closely related processes. For example, the Galapagos Island Finches.

Evolutionary Adaptations
Adaptation = any trait that aids in the survival and reproductive success of an organism Structural Adaptations: Arise over many generations Physiological Adaptation: Changes in metabolic processes Can develop rapidly Ex. Penicillin- introduced 50 years ago, now many bacteria are resistant.

Natural Selection Darwin proposed natural selection as the mechanism for evolutionary adaptation of populations to their environments. Population of organisms Hereditary variations Differences in reproductive success Evolution of adaptations in the population Overproduction and struggle for existence Figure 1.20

Darwin’s 5 Points A population has heritable variation. (Variety in a population is essential for evolution to occur). Some variations are favorable (they increase fitness). Overproduction- more offspring are produced than survive. Differential survival- offspring with favorable traits (greater fitness) are more likely to survive and reproduce. A population will change over time as a result.

Natural Selection Darwin proposed natural selection as the mechanism for evolutionary adaptation of populations to their environments. Survival of the Fittest: those individuals with higher levels of fitness survive and reproduce most successfully. Fitness: the ability of an organism to survive and reproduce in its specific environment. Population of organisms Hereditary variations Differences in reproductive success Evolution of adaptations in the population Overproduction and struggle for existence Figure 1.20

Natural Selection Natural selection is the evolutionary process that occurs when a population’s heritable variations are exposed to environmental factors that favor the reproductive success of some individuals over others. Ghost Mantid

Natural Selection

Natural Selection Does NOT create new traits, but selects for traits that help individuals survive and reproduce more successfully in their environment. Ex. does not create antibiotic resistance in bacteria, but selects for bacteria that are already resistant. Selection depends on time and place. Favors traits that are beneficial in the current environment Changes in the environment can cause once advantageous traits to become useless or detrimental (ex. arctic fox coat color)

Bellwork 1/13/16

Agenda 1/13/16- Evidence for Evolution
Bellwork Evidence for Evolution Goldfish lab

Artificial vs. Natural Selection
Artificial Selection: nature provides the variation, humans select those variations they find desirable Selective breeding Natural Selection: nature provides the variation, but the traits being selected increase an organism’s fitness in its environment Survival of the Fittest

Artificial Selection In the process of artificial selection, humans have modified other species over many generations by selecting and breeding individuals that possess desired traits. Figure 22.10 Terminal bud Lateral buds Brussels sprouts Cabbage Flower cluster Leaves Cauliflower and stems Broccoli Wild mustard Kohlrabi Stem Kale

Summary of Evolution by Natural Selection
There is no predetermined path for evolution. The way species look and behave today is a response to some past selection event and/or suite of environmental conditions. Species are playing a constant game of catch up.

Evidence for Evolution
Fossil Record- studied by paleontologists Mostly found in sedimentary rock Shows order of sequences of fossils as they appear in rock layers Shows when organisms appeared or disappeared Can show evolutionary changes over time Pieces are missing, but the overall picture is understood

Great Transformations
The Darwinian view of life predicts that evolutionary transitions should leave signs in the fossil record. Paleontologists have discovered fossils of many such transitional forms

Evidence for Evolution: Fossils and Morphological Evidence Fish to Land Animals- Transitional Fossils

Evidence for Evolution Fossils and Relative Dating
Relative Dating: determines the age of rocks/fossils compared to other rocks/fossils. lower layers of rock are older and upper layers are younger, compared to each other. QUALITATIVE data- doesn’t tell exact age

Evidence for Evolution Fossils and Relative Dating
Radiometric Dating Finds the absolute age of fossils Based on the decay of radioactive isotopes Breakdown rate (half life) determines the age of the fossil

Biogeography The geographic distribution of species Island species often resemble close-by mainland species Areas of isolation have evolved unique species (ex. Australia marsupials) Supports Darwin’s theory that today’s organisms evolved from common ancestral forms

Evidence for Evolution 2
Evidence for Evolution 2. Biogeography: Continental Drift and Plate Tectonics The Earth’s plates move gradually over time. For example, North America and Europe are currently moving apart at a rate of about 5 cm per year Pangea, the “supercontinent,” formed about 225 million years ago, causing the Permian Extinction Influences geographic distribution of organisms

Evidence For Evolution Plate Tectonics

Relative vs Radiometric Dating
Complete the worksheet in pairs.

Quackers Lab Complete the lab in pairs.
This lab activity will model the process of natural selection, which is the mechanism behind evolution of populations.

Agenda 1/14- Modern Synthesis
Bellwork New Information- Finish evidence for evolution notes Start Modern Synthesis notes: Darwin meets genetics Lab/Activity- Darwin’s Finches HW- finish graphs

Bellwork 1/14/15

3. Comparative Anatomy The comparison of body structures between different species Homologous Structures a modified structure seen among different groups of descendants (result of divergent evolution) Arise from same embryonic tissue Provides evidence that the organisms evolved from a common ancestor

3. Comparative Anatomy The comparison of body structures between different species Vestigial Structures Structures reduced in function or functionless, but were once used by ancestral organism Indicate evolutionary pathways Ex. appendix, pelvic bones in whales and snakes, human ear muscles, etc. The muscles connected to the ears of a human do not develop enough to have the same mobility allowed to monkeys.

3. Comparative Anatomy The comparison of body structures between different species Analogous Structures Similar in function but not in structure (comes from different embryonic tissue) Does NOT show recent common ancestry, but shows that organisms adapt to similar environmental pressures in similar ways Result of convergent evolution mammal bird marsupial placental mammal

Evidence for Evolution: 4. Comparative Embryology
Comparison of anatomical structures that appear during the early stages of development Closely related organisms have many similar stages in their embryological development Shows common ancestry

Evidence for Evolution: 4. Comparative Embryology
Ex. Most vertebrate embryos have pharyngeal slits and tails Embryos become more distinct as they develop Salamander Turtle Chicken Rabbit Human

Evidence for Evolution: 5. Molecular Biology
Universal genetic code (DNA, RNA) DNA code- comparisons of nucleotide sequences can tell us how closely related organisms are to one another Similar/Same molecules and processes Proteins/enzymes, ATP, etc. Examples: Mitochondrial DNA can be traced to a single group of women living in West Africa about 200,000 years ago (Mitochondrial Eve) Human and chimpanzee DNA is remarkably similar, with only 1.2 % difference among those genes we both share in common (and only 4-5% difference in the entire genome).

Part 1 of The Evolutionary Arms Race
Watch the video, answer the questions on the worksheet.

Bellwork 1/15

Agenda 1/15- Patterns of Evolution
Bellwork Card sort activity Notes- Modern Synthesis (Darwin meets genetics) Finish Finch Lab HW- evolution review worksheet; quiz next Wednesday.

The Modern Synthesis- Darwin meets Genetics, mid 1900s
General Concepts Populations evolve, individuals DO NOT!! There is genetic variation within populations (genetic diversity) Microevolution Macroevolution (Really, micro- and macroevolution are the same thing, just on different time scales).

1. Population Genetics New features cannot evolve in response to natural selection within the lifetime of one individual. (Individuals CANNOT evolve!) Populations are the smallest biological unit that can evolve. Natural selection generally operates on populations over many generations.

1. Population Genetics Looks at the gene pool of a species
Gene Pool = all of the alleles in a population at any one time. Evolution is the result of changes in a population’s gene pool. Ex. green or brown allele for insect color

1. Population Genetics Mutation adds new allele(s) to gene pool.
Sometimes these alleles add favorable variations to the population. Natural selection will result in an increase in favorable variations in future generations.

2. Genetic Variation There is genetic variation within populations
Sources of genetic variation Mutations Gene shuffling (ex. crossing over during meiosis) Heritable variation allows population change in response to environmental changes/natural selection events Peppered moths

3. Microevolution A change in a population’s allele frequencies from generation to generation. Changes the gene pool. Caused by Genetic drift Mutation Gene flow Natural Selection

Causes of Genetic Change in Population: Genetic Drift
Random change in allele frequency in a population Usually apparent in small populations Changes in allele frequency are not based on fitness

Causes of Genetic Drift- 1. Founder Effect
A few individuals colonize a new area The gene pool of the small founder population often has less variety than the original population. Sample of Original Population

Causes of Genetic Drift: Founder Effect
Genetic Drift - random change in allele frequency in a population Sample of Original Population Founding Population A Founding Population B A few individuals colonize a new area The gene pool of the small founder population often has less variety than the original population.

Causes of Genetic Drift: Founder Effect
Founder Effect- Over time, the new colony may become genetically distinct from the parent population. Sample of Original Population Founding Population A Founding Population B Descendants

Causes of Genetic Drift
2. Bottleneck Effect - Large numbers of individuals die, leaving behind a small surviving population. - Likely to have smaller gene pool than original population; reduces genetic variation in population. Ex. Endangered species; cheetahs

Cheetahs

Microevolution 3. Gene Flow-
A population may gain or lose alleles when individuals move into or out of the population Increased gene flow tends to reduce differences between populations

Microevolution 4. Mutations The raw material for evolution!
New alleles form by mutations in DNA. Can immediately change the gene pool. Frequency of new alleles increases if those with the mutation reproduce. Increase in mutant alleles is the result of natural selection and/or genetic drift.

Frequency of Phenotype
Polygenic Trait - a trait with a frequency distribution that resembles a bell (bell curve) because there is more than one gene controlling the trait Phenotype - the physical appearance a gene produces Frequency of Phenotype Phenotype (Beak Depth)

Types of Natural Selection (Microevolution)
Directional Selection Disruptive Selection Stabilizing Selection (most common)

Kinds of Natural Selection
Directional Selection: One extreme form of the trait is favored; occurs as a result of a changing environment Ex. shift towards larger beak size Key Low mortality, high fitness High mortality, low fitness Directional Selection Food becomes scarce.

Kinds of Natural Selection
Disruptive Selective- Individuals at both extremes of a trait are selected for found in patchy environments that offer different localized conditions Ex. smallest and largest beaks are selected for Disruptive Selection Largest and smallest seeds become more common. Number of Birds in Population Beak Size Population splits into two subgroups specializing in different seeds. Key Low mortality, high fitness High mortality, low fitness

Stabilizing Selection
Kinds of Natural Selection Stabilizing Selection- favors average individuals in the population Found in relatively stable environments Ex. smallest and largest beaks are selected against Key Percentage of Population Birth Weight Selection against both extremes keep curve narrow and in same place. Low mortality, high fitness High mortality, low fitness Stabilizing Selection

Agenda 1/19- Bellwork Notes: Speciation, Macroevolution- Patterns of Evolution Video clip- The Beak of the Finch, questions Geologic Time Activity (if time)

The graph below relates the number of gray squirrels in a small population to their coat colors.
This squirrel population has been separated from other squirrel populations by a new highway and several construction sites. The main predators of these squirrels are cats and hawks. Assume that light gray squirrels are very visible in this new environment. What is likely to happen to the distribution of coat color in this squirrel population over several generations? Sketch a graph to show the predicted distribution. Assume that dark gray squirrels are very visible on the ground, and light gray squirrels are very visible in the trees. Sketch a graph showing what is likely to happen to the distribution of coat color in the squirrel population over several generations.

4. Macroevolution The major changes in the history of life
Includes the study of The origin of new species (= speciation) The explosive diversification of life Mass extinctions and subsequent adaptive radiation

Are Darwin’s Finches still evolving?
Is speciation occurring in Darwin’s Finches?

Is speciation occurring in Darwin’s Finches? Rosemary and Peter Grant, Princeton University “Speciation begins when a single population forms two independently diverging lineages, each taking a different evolutionary trajectory.” Geospiza fortis Grant, Peter R Ecology and Evolution of Darwin’s Finches. Princeton Univ. Press, Princeton, NJ.

Speciation- the formation of a new species
Are Darwin’s Finches still evolving? Is speciation occurring in Darwin’s Finches? Rosemary and Peter Grant, Princeton University Speciation- the formation of a new species Geospiza fortis Grant, Peter R Ecology and Evolution of Darwin’s Finches. Princeton Univ. Press, Princeton, NJ.

Speciation (click for video)
The formation of one or more new species from a parent species A new species is formed when they are prevented from interbreeding or producing fertile offspring with the parent species

Mechanisms of Speciation
Requires significant changes in the gene pool Two general scenarios: Allopatric Speciation- Physical Barrier Geographic isolation- stops or significantly slows gene flow (leads to reproductive isolation) Takes many generations Sympatric Speciation

Mechanisms of Speciation
Requires significant changes in the gene pool Two general scenarios: Allopatric Speciation- Physical Barrier Sympatric Speciation New species becomes reproductively isolated in the midst of the parent population No geographic isolation- can happen rapidly (just one generation) Rare- more common in plants (polyploidy) Ex. behavioral, temporal isolation

Is speciation occurring in Darwin’s Finches? Geospiza fortis Grant, Peter R Ecology and Evolution of Darwin’s Finches. Princeton Univ. Press, Princeton, NJ.

Is speciation occurring in Darwin’s Finches? Geospiza fortis

This shift in beak depths is evidence that there is potential for evolution to occur and that evolution may in fact be occurring. Geospiza fortis

Is speciation occurring in Darwin’s Finches?
Not yet. In order for speciation to occur, two populations with different beak depths would have to become reproductively isolated. Geospiza fortis

What would speciation look like?
More frequent droughts force smaller beaked birds to move to another island with smaller, drought tolerant seeds.

Reproductive isolation and different environmental (food) influence.

No gene flow between islands.

What are the requirements for speciation?
Isolating Mechanisms The beginning of two new species?

Isolating Mechanisms- Reproductive Isolation is required for speciation to occur. There are 3 types… Geographic Isolation Island A Island B

Isolating Mechanisms Behavioral Isolation Mating Call A Mating Call B

Isolating Mechanisms Temporal (time) Isolation Spring Mating Autumn Mating

Darwin’s Finches Lab Work in groups of 2. Compare your graphs (beak depth for 1976 or 1978 population). Share your answers to the questions and make any changes.

Agenda 1/20/16- Macroevolution
Bellwork- none New Information: Macroevolution- patterns of evolution Sexual vs. Asexual Reproduction and Evolution Classification activity Quiz tomorrow Review crossword and graphic organizer

Patterns of Evolution- Macroevolution
Mass Extinctions Adaptive Radiation Convergent Evolution Coevolution Gradualism vs. Punctuated Equilibrium

Patterns of Evolution Adaptive Radiation
When one ancestral species evolves into several new species Example: Darwin’s finches. One species of finch evolved into more than a dozen in the Galapagos

Adaptive Radiation Occurs when niches open up, especially after a mass extinction Example: A mass extinction got rid of the dinosaurs and left lots of niches for mammals to adapt, radiate and dominate for the next 65 million years 6 Mass Extinctions Is one occurring now?

Evidence for Evolution Convergent Evolution
bird Occurs when “unrelated” organisms adapt to similar environments. Species look similar, but they got those traits through very different processes. Adaptations increase fitness in a specific environment- the same selective pressures result in similar (analogous) structures. mammal 97

Patterns of Evolution Coevolution (click for video)
Process by which two species evolve in response to changes in each other over time Predator/Prey, Plant/Herbivore, Plant/Pollinator (ex. Bee Orchid)

Patterns of Evolution Gradualism:
slow, gradual pattern of evolution Punctuated Equilibrium: pattern of long, stable periods punctuated by brief periods of more rapid change

Why Sex? The Evolution of Sexual Reproduction
offspring are a combination of parents introduces variety in population Asexual Reproduction offspring are identical to parents little variety in population

The Evolution of Sexual Reproduction

The Red Queen Hypothesis The Evolution of Sexual Reproduction
The leading hypothesis for why sexual reproduction has persisted Refers to Lewis Carroll’s Through the Looking Glass The Red Queen says to Alice: “It takes all the running you can do, to stay in the same place.”

The Red Queen Hypothesis The Evolution of Sexual Reproduction
As species that live at each other's expense co-evolve, they are engaged in a constant evolutionary struggle for a survival advantage. They need "all the running they can do" because the landscape around them is constantly changing. (predator/prey, disease/host) In other words, hosts change the locks, and parasites, etc invent new keys. Sexual reproduction is necessary to fight disease, avoid predation, get food, etc.

Why Sex? Advantages and Disadvantages of Asexual Reproduction
Pass on all of your genes No mating behavior costs (don’t have to spend time or energy looking for a mate, no energy wasted on showy displays) Disadvantages: Little or no variation More susceptible to parasites, viruses, etc. Sexual Reproduction Advantages: Variation More rapid rate of adaptation in a changing environment Disadvantages: Costs of mating behavior: competition, no mating Only pass on half your genes At 7:46-

Costs of Sexual Reproduction: Displays, Competition for Mates

Agenda 1/21 Evolution Quiz Classification review, endosymbiotic theory
Classification activities HW- 3rd page of review packet, front and back

Classification: A way to organize the diversity of life.
Carolus Linnaeus binomial nomenclature system Scientific names: Genus species In Latin Binomial nomenclature (bi- = 2; nomial= name) Italics; first word capitalized, second word lowercase

8 Taxonomic Categories Domain Dear Kingdom King Phylum Philip
Class Came Order Over Family For Genus Great Species Spaghetti

Human Classification Domain- Eukarya Kingdom- Animalia
Phylum- Chordata Class- Mammalia Order- Primates Family- Hominidae Genus- Homo Species- sapiens Scientific name- Homo sapiens Each organism has a unique scientific name, which includes the genus and species categories.

Problems with Traditional Classification
Morphology (physical characteristics) isn’t always an accurate reflection of evolutionary relationships Example- Dolphins “look” like fish, so they were classified as such for a long time. Dolphins are not fish, however. They are mammals, more closely related to whales, cows, pigs, and hippos than to fish.

Evolutionary Classification
No longer based solely on physical characteristics Categories better reflect evolutionary relationships DNA/RNA- mutations (molecular clocks) Appendages Conical Shells Crustaceans Gastropod Crab Barnacle Limpet Crab Barnacle Limpet Molted exoskeleton Segmentation Tiny free-swimming larva TRADITIONAL CLASSIFICATION CLADOGRAM

Three Domain System Domain Eukarya Domain Bacteria Domain Archaea
Domain is the most inclusive category (above Kingdoms) Domain Eukarya Kingdoms Animalia, Plantae, Fungi, and Protista Domain Bacteria Kingdom Eubacteria Domain Archaea Kingdom Archaebacteria

Textbook, page 459 Protista Fungi Plantae Animalia Eubacteria
DOMAIN BACTERIA ARCHAEA EUKARYA KINGDOM Eubacteria Archaeba cteria Protista Fungi Plantae Animalia CELL TYPE Prokaryote Eukaryote CELL STRUCTURE Cell walls with peptido- glycan Cell walls w/o peptido- glycan Cell walls in some, some w/ chloroplasts Cell walls of chitin Cell walls of cellulose; chloroplasts No cell walls or chloroplasts # OF CELLS Unicellular Most multi-cellular Multi-cellular MODE OF NUTRITION Auto- or hetero-troph Hetero- troph Autotroph EXAMPLES Strepto- coccus halophiles Amoeba, Paramecia Mushrooms, yeast Flowering plants Sponges, worms, mammals

What Was the Origin of Life?
The Oparin and Haldane Hypothesis Aleksandr Oparin (1924) and John Haldane (1929) independently proposed very similar hypotheses for the origin of life: Their combined hypothesis stated that conditions on the primitive earth favored chemical reactions that synthesized organic compounds from inorganic precursors. The Miller-Urey Experiment 1953, University of Chicago Figure 17-8, page 424

Origin of Organic Molecules
Mixture of gases simulating atmospheres of early Earth: Methane Ammonia Hydrogen Water Spark simulating lightning storms Figure 17-8 page 424 The Miller-Urey Experiment 1953, University of Chicago Condensation chamber Cold water cools chamber, causing droplets to form Water vapor Liquid containing amino acids and other organic compounds

How did complex cells evolve
How did complex cells evolve? The Endosymbiotic Theory Figure 17-12, page 427 Plants and plantlike protists Chloroplast Aerobic bacteria Ancient Prokaryotes Photosynthetic bacteria Nuclear envelope evolving Mitochondrion Primitive Photosynthetic Eukaryote Animals, fungi, and non-plantlike protists Ancient Anaerobic Prokaryote Primitive Aerobic Eukaryote

The Evolution of Photosynthesis
The Endosymbiotic Theory Chloroplast How did the presence of photosynthetic bacteria, and eventually plants, affect the atmosphere? Photosynthesis led to increased atmospheric oxygen levels Biological importance: evolution of cellular respiration Geological importance: caused rust to form for the first time Figure 17-12

Origin of Respiration The Endosymbiotic Theory Figure 17-12, page 427
How did this increase in atmospheric oxygen affect metabolism? More atmospheric oxygen allowed mitochondria to become an essential component of cells. 18 times more ATP produced with aerobic respiration, which made aerobic cells more energetically competitive in an oxygen-rich environment Mitochondria

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