evolution notes

Evolution NotesZoology

Mrs. McCarthyApril 22, 2023

I. What is evolution?A. Evolution is any change in the genes of a

population over timeB. Examples:

1. Antibiotic resistance in bacteria2. Loss of legs by snakes and whales

II. Different kinds of theories of how the world became as it is today

A. Big Bang – explosion of a mass of matter to create the universe (solar system ~ 4.6 billion years old)

B. Creationism – Everything created by a divine beingC. Spontaneous generation – life “just appears”

II. Different kinds of theories of how the world became as it is today

D. Abiogenic molecular evolution1. Organic molecules gradually assembled from inorganic elements2. Haldane’s beliefa. “Hot dilute soup” – Earth’s primitive atmosphere had H2O, CO2, ammoniab. Organic molecules formed with energy from UV radiation

II. Different kinds of theories of how the world became as it is today

3. Oparin’s beliefa. Energy from the sun, lightning, and

volcanic heat formed organic molecules

II. Different kinds of theories of how the world became as it is today

E. Evolution – gradualism – SLOW change over time1. First life was probably a “protocell”a. membrane bound cell that reproducedb. Heterotrophic (photosynthesis came later)c. Prokaryotic – early bacteria2. Probably happened 4 billion years BP (before the present)3. Life may have originated more than once!

III. History of Evolutionary Theory

A. Jean Baptiste de Lamarck – French biologist1. First to notice that fossils were remains of past life2. Lamarckism, or The Theory of Use and Disuse

a. organisms acquire adaptations during their lifetime and pass them on to their

offspring

III. History of Evolutionary Theory

b. examples:1. Snakes lost legs to move well in

dense vegetation2. Giraffes developed long necks

from stretching3. Any change would be passed on

to their offspring3. This theory was later disproved by genetics

If Lamarckism was true, women wouldn’t need to do this:

Or this:

III. History of Evolutionary Theory

B. Charles Darwin – English naturalist1. Life history

a. expelled from medical school, not good student

b. 22 years old, became naturalist for H.M.S. Beagle

c. (almost wasn’t accepted, captain didn’t like the shape of Darwin’s nose)

III. History of Evolutionary Theory

d. made extensive collections of flora/fauna on his 5 year journey

e. spent time in Galapagos Islands – noticed different organisms

f. published The Origin of Species

III. History of Evolutionary Theory

2. Developed the theory of Natural Selection – survival of the fittesta. ALL organisms show variationb. more offspring are produced than can survivec. struggle for survival (to meet basic needs)d. some have a better chance for survival than otherse. survival of the fittestf. new species originate

III. History of Evolutionary Theory

3. Darwin believed that genes of parents blend in the offspring

a. Gregor Mendel’s studies in genetics proved this incorrect

IV. Support for the theory of evolution

A. Sequence of fossil types1. Fossils – evidence of past life (bones, teeth,

shells, imprints, coprolites)2. Rocks are formed in layers – older rocks are

deeper3. Fossils in old layers are older and more simple

IV. Support for the theory of evolution

B. Vestigial organs – have no CURRENT function1. Appendix2. Wisdom teeth3. Wings on flightless birds4. Little toe

IV. Support for the theory of evolution

C. Homologous Structures1. Same structures, but different functions2. Shows origin in a common ancestor3. Vertebrate pentadactyl limb

a. human armb. horse legc. bird wingd. whale flippere. bat wing

IV. Support for the theory of evolution

D. Embryological Development1. Organisms go through similar development2. Humans had gill slits, tail, fine covering of hair

IV. Support for the theory of evolution

E. Agricultural/Animal Domestication1. Selective breeding (pets, farm animals, crops)2. Each generation is not the same

IV. Support for the theory of evolution

F. Competition for Existence1. More animals produced than could ever survive2. Compete for food, water, shelter, mates

IV. Support for the theory of evolution

G. Genetics1. Genetic variation 2. Change in gene frequencies over time

IV. Support for the theory of evolution

H. Wiesmann’s Continuity of Germplasm1. Sex cells must change for evolution to occur

IV. Support for the theory of evolution

I. DeVrie’s Theory of Mutations1. Change is caused by mutations

V. Example of Natural Selection

A. Microevolution – change of genes in one populationB. Peppered moth in England

1. Industrial melanism (change in color)2. Moths were originally white or peppered gray3. Industrial revolution caused pollution4. Soot covered trees, causing them to be darker5. Birds saw and ate light moths on dark trees6. Dark “mutations” of the moth could blend in and

survive7. Population shifted to the dark version of the moth

Peppered Moth

Mimicry as an adaptation

Ladybug Adaptations

Poisonous Frog Adaptations

Crocodile Adaptations

Crane Adaptations

VI. Speciation – development of new species

A. Reproductive isolation1. Groups of same species can not contact

each other2. Adapt to separate environments3. Develop into different species

VI. SpeciationB. Allopatric speciation – complete geographic

isolation of populations

VI. SpeciationC. Adaptive radiation

1. One common ancestor develops into different species based on

competition, location, food supply2. Example: Darwin’s finches

VI. SpeciationD. Punctuated Equilibrium – Eldredge and Gould

1. Macroevolution – large evolutionary changes

2. New species suddenly emerge3. Species change little, become extinct4. Explains the gaps in the fossil record

VI. Speciation video clip

VI. SpeciationE. Hardy – Weinberg Equilibrium

1. Mathematical formula to prove genes remain constant under certain

conditionsa. large populationsb. random matingc. no mutationsd. no selection (survival of the fittest)e. no migration