Evolution

I. The Origin Of LifeA. Evolution = Species change over time

B. Biogenesis = Life from life1. Experiments disprove spontaneous

generation

a) Francisco Redi (1668)- Flies only come from egg’s of other flies

I. The Origin Of Lifeb) Lazzaro Spallanzani (1700’s)

1) Air doesn’t form microorganisms

2) Boiled broth did not grow microorganisms

3) Opponents said boiling destroyed the “vital force” in air

I. The Origin Of Lifec) Louis Pasteur (1800’s)

1) Boiled broth in curved-neck flask (allows air in)

2) No microorganisms form till curved neck is removed

I. The Origin Of LifeC. Earth’s History

1. Earth is 4.6 billion years old2. Radioactive Dating

a) Radioactive isotopes are used to date fossils.b) The isotopes decay at a constant known rate.c) The time it takes for one half of the radioactive material

to decay is called the half-life.

I. The Origin Of Life3. Organic Compounds

a) Oparin /Haldane (1923)

1) Early earth contained ammonia, hydrogen, water vapor, and methane

2) No Oxygen

3) Volcanic energy, lightning, and UV radiation could create amino acids.

OparinHaldane

I. The Origin Of Lifeb) Stanley Miller &

Harold Urey (1953)

1) Experimented with Oparin’s hypothesis

2) Created all 20 amino acids, nitrogen bases, and ATP

c) Sidney Fox

1) Produced proteinoids (abiotic polypeptides)

2) Dripped organic monomers on hot sand, clay or rock

Urey Miller

I. The Origin Of Life4. First Life-Forms

a) Thomas Cech1) Ribozymes can act

as enzymes and self-replicate

2) RNA appears to be the first genetic material

b) Anaerobic prokaryotes appear about 4 billion years ago

c) Photosynthetic prokaryotes appear 3.5 billion years ago

d) Oxygen levels increase

I. The Origin Of Lifee) Ozone protects life from UV radiationf) Eukaryotes appear 2 billion years ago

1) Evolve by Endosymbiosis2) Mutualism between small aerobic prokaryotes and

larger anaerobic prokaryotes3) Gave rise to mitochondria and chloroplasts

Autotrophicbacteria Anaerobic

heterotrophic bacteria

became mitochondriaand chloroplasts

What is endosymbiosis?Explain natural selection in your own

words. Use the following words: genetic variation, adaptation, overpopulation, struggle for existence.

(minimum of 5 sentences; use text)

II. Theories of EvolutionA. James Hutton (1726-1797)

1. Geologist2. Gradualism (1795)

a) Processes today are the same as in the past

b) Large changes are the accumulation of slow, continuous processes.

II. Theories of EvolutionB. Thomas Malthus (1766-1834)

1. Published essay on human population (1798)

2. Resources control populations

3. Influences Darwin on his ideas about organism’s struggle for existence

II. Theories of EvolutionC. Jean Baptiste Lamarck (1744-1829)

1. Naturalist2. Inheritance of acquired

characteristics (1809)a) Organisms change in

response to the environment.b) Structures that are used

become stronger, and structures that are not used become weaker.

c) Pass new trait to kids

II. Theories of EvolutionD. Charles Lyell (1797-1875)

1. Geologist2. Proposed Uniformitarianism

(1830)3. Processes that occur today

have always occurred

II. Theories of EvolutionE. Charles Darwin (1809-1882)

1. Naturalist2. HMS Beagle (1831)

a) Made observations in the Galapagos

b) Noted differences in finches on each island

3. 1844- begins writing The Origin of Species

II. Theories of Evolution4. Alfred Wallace (1823-1913)

a) Sends manuscript on natural selection to Darwin (1858)

b) Published that year5. Darwin publishes The

Origin of Species (1859)a) Descent with

Modificationb) Natural Selection is

mechanism6. Adaptive advantages are

determined by nature7. Fitness is an individual’s

gene contribution to the next generation

III. Evidence of EvolutionA. Evidence from Fossils

1. Types: Imprints, molds (impressions), casts (filled impression), tracks, hard parts, actual remains.

2. Dating Fossils

a) Absolute Dating- Radioactive isotopes

b) Relative Dating

1) Sediments are layed down in strata

2) Lowest layers are oldest

3) A fossil's position in undisturbed rock gives its age relative to other fossils.

III. Evidence of Evolution3. The Fossil Record

a) Creates the Geologic Time Scale

b) Oldest fossils found are 3.5 billion years old and are prokaryotic cells (bacteria).

c) Fossils show earth's changes (Organisms, Climate, Environment)

4. Biogeography- geographical distribution of species.

4. Biogeography- geographical distribution of species.

III. Evidence of EvolutionB. Evidence from Living Organisms

1. Homologous Structuresa) Similar features that

originate in a shared ancestor

b) Structures may have different uses in adult, but come from same tissue in embryo.

c) Analogous Structures1) Identical functions2) No embryo tissue in

common3) Not closely related

III. Evidence of Evolution2. Vestigial Organs

a) Structures that serve no useful purpose.

b) Shows relationship to organisms in which the structure is functional.

3. Embryologya) Similarities of embryosb) Embryo development repeats

evolutionary history

III. Evidence of Evolution4. Biochemistry

a) Enzymes and structures for important biological pathways are universal (respiration, photosynthesis)

b) The more similar the amino acid sequences, the more closely related the species.

c) Universal genetic code

IV. Evolution of PopulationsA. Populations are the smallest

unit that can evolve (adapt)B. Variation exists in a population

1. Due to resources- food, soil2. Due to heredity- genotype

C. Cause of variation in Genotypes1. Mutation2. Recombination (independent

assortment, crossing-over)3. Random fusion of gametes

IV. Evolution of PopulationsD. Gene Pool

1. All genetic information in a population

2. Frequency of a certain allele in a population will determine the phenotype frequency

E. Hardy-Weinberg Equilibrium

1. Allele frequencies stay the same in an undisturbed population (genetic equilibrium)

2. Allows scientists to measure changes in a gene pool

V. Disruption of Genetic Equilibrium

A. Mutation1. Caused by mutagens2. Change DNA

producing totally new alleles

3. Most are harmfulB. Migration

1. Immigration and emigration of individuals

2. Ensures gene flow

V. Disruption of Genetic Equilibrium

C. Genetic Drift

1. Change of allele frequencies due to random events

2. Small populations are highly affected

D. Nonrandom Mating

1. Geographic proximity

2. Assortive mating- like to like

V. Disruption of Genetic Equilibrium

E. Natural Selection1. Most significant factor in evolution of

populations2. Nature selects against non-fit

individuals3. Reduces harmful alleles

V. Disruption of Genetic Equilibrium4. Types

a) Stabilizing Selection- towards the average

b) Directional Selection- towards one extreme

c) Disruptive Selection- away from the average

d) Sexual Selection- females tend to choose

VI. Speciation= 1 species becomes 2A. When populations become

significantly differentB. Morphological Species

Concept1. Physically different2. Problem- individual variation

C. Biological Species Concept1. Proposed by Ernst Mayr2. A population that can

interbreed3. Problem- Extinct species?

D. Modern Species Concept1. Morphologically similar2. Can interbreed to produce

fertile offspring3. Biochemistry –DNA, Proteins

VI. SpeciationE. Extinction can be a natural process

1. When conditions change too rapidly

2. When a species is out competed

3. When specialization restricts a lifestyle and conditions change

VII. Human EvolutionA. Hominids are extinct humans

and immediate ancestorsB. All hominids are primates

1. Moveable fingers and toes2. Nails instead of claws3. Color vision (unusual for

mammals)4. Binocular Vision

VII. Human EvolutionC. The First Hominids

1. Australopithecusa) A. afarensis (3 to 3.9 mya)

1) Lucy2) Walked upright

b) A. africanus (2.3 to 3 mya)1) Taller and heavier than

Lucy2) Slightly larger brain3) Probably not our direct

ancestor

VII. Human Evolution2. Genus Homo

a) H. habilis (1.6 to 2.5 mya)

1) “handy human”

2) Stone tools

b) H. erectus (1.8 mya to 500,000 ya)

1) “upright human”

2) Hunted and used fire

3) Typical “cave-man”

VII. Human Evolutionc) H. sapiens (800,000 ya)

1) Neanderthals (230,000 to 300,000 ya)

2) Cro-Magnons (100,000 ya)

a. Modern humans

b. Out competed H. erectus and Neanderthals

VII. Human EvolutionD. African-origin Hypothesis

1. Based on similarities in mitochondrial DNA

2. Modern humans came from Africa 100000 to 200000 years ago.