The History of Evolution

I. Basic TerminologyA.Evolution- The process of

change in life forms over time.B. Species- a group of individuals

with similar anatomical characteristics and capable of interbreeding to produce fertile offspring.

Basic TerminologyC. Variation-Differences in

characteristics among individuals of a species

D. Adaptation-Any alteration of structure, behavior, or function that makes an organism more reproductively successful.

Basic TerminologyE. Speciation- The evidence of new species

evolvingF. Phylogeny- The evolutionary history of

a speciesG. Camouflage- blend into their

surroundingsH. Diversity- the number and relative

abundance of species in a biological community

Basic Terminology

• I. Extinction-coming to an end or dying out of a species or other taxon

• J. Mimicry• K. Natural Selection• L. Vestigal Structure

II. Lamarck 1744-1829

A.1809 First to complete theory on evolution

B. Lamarck’s Theory:Theory of Inheritance of Acquired

Characteristics 1. Organisms are capable of changing their

form, proportions, color, agility etc. In response to a specific environmental change.

2. The more they use a particular body part the stronger and better developed that part becomes

3. The physical characteristics that an organism develops through use or disuse can be passed on to their offspring

C. Example1. Giraffe stretches

its neck to reach food, it then passed this trait to it’s children …so giraffes have long necks

III. Charles Darwin ( 1809-1882)

A. Father of the modern theory of evolution

B. In 1836 accompanied the Beagle on a scientific expedition (S. America and S. Pacific) as an naturalist

C. He observed variations in animals and plants from different continents; fossil record and geological formation.

D. Galapagos Islands( sm. Islands 1000km off the West Coast of S. America)

1. Observed tortoises, mockingbirds, finches and other species

2. Noted that each island supported its own form of animal and plant life

3. These were closely related yet different from island to island.

D. Darwin’s Survival of the Fittest!

• Explanation for Evolution:Natural Selection:Individuals that have physical

or behavioral traits that better suit their environment are more likely to survive and will reproduce more successfully than those that do not have such traits.

E. Darwin’s Natural Selection Theory

1. Natural Selection: Mechanism for change in a population that occurs when organisms with favorable variations for a particular environment survive, reproduce, and pass these variations on to the next generation

C. Malthus vs. DarwinMalthus believed the availability of a

food supply influenced human population

1. Darwin believed in struggles for existence: Competition-a. Foodb. Spacec. Escape from predators

F. On the Origin of Species by Natural Selection

1. Published in 1859

2. Believed that the earth is not static, but always evolving.

Darwin vs. Lamarck• Darwin believed that the desires of animals have nothing to do with how

they evolve, and that changes in an organism during its life do not affect the evolution of the species. He said that organisms, even of the same species, are all different and that those which happen to have variations that help them to survive in their environments survive and have more offspring. The offspring are born with their parents' helpful traits, and as they reproduce, individuals with that trait make up more of the population. Other individuals, that are not so well adapted, die off. Most elephants used to have short trunks, but some had longer trunks. When there was no food or water that they could reach with their short trunks, the ones with short trunks died off, and the ones with long trunks survived and reproduced. Eventually, all of the elephants had long trunks. Darwin also believed that evolution does not happen according to any sort of plan.

IV. R.A. Fisher 1930A. 1st attempt to

combine Darwin’s theory of natural selection with Mendel’s Laws

B. The Genetical Theory of Natural Selection

V. Thomas Hunt Morgan 1932

A. Discovered mutation changes in DNA that can cause variation

B. Mutation can bring about evolutionary change

C. Fruit Fly experiments

Adaptations: Evidence of Evolution

According to Darwin

I. Structural Adaptations-can develop over millions of years

A. Ex. Teeth and claws of a mole-rat

B. Mimicry: enables one species to look like another species

C. Camouflage: blend into their surroundings

II. Physiological Adaptations-can develop more rapidly

A. Bacteria resistance to antibiotics

Ex. PenicillinB. Insects

resistance to pesticides

III. Fossils-Indirect Evidence of Evolution

A.Record of earlier life

B.Incomplete fossil record

C.Horse

IV. Anatomical StudiesA. Evolutionary

RelationshipsB. Structural similarities as

evidence that organisms evolved from a common ancestor

C. Homologous Structures-similar in arrangement and/or function-evolutionary origin

Anatomical StructuresD. Analogous

Structures-don’t have a common evolutionary origin, but are similar in function but not structure

… Independently adapted to similar ways of life

V. Vestigial StructuresA. Body structure that is reduced

in function in a living organism-but may have been used in an ancestor.

B. Ex. Eyes on cave fishC. Ex. Flightless Birds with wingsD. Ex.Whales with pelvic bonesE. Ex. Appendix

VI. DNA Comparisons

• DNA and Protein sequences

• Related animals share more DNA and have more amino acids in common