What is gradualism and punctuated evolution?

Agenda for Monday Nov 15th 1.Finish Fossil Lab2.Theories of Evolution Notes: Lamarck

1. Lamarck’s Giraffes

Theories of Evolution• Evolution – change in the inherited traits of a

population of organisms over time• 2 Main contributors– Lamarck and Darwin

Jean Baptiste de Lamarck

• Proposed similar species descended from a common ancestor

• Living species were descended from similar extinct species

Lamarck• Use and disuse of organs– developing/changing structure and function of old

organs

• Inheritance of acquired traits– Acquired trait – a trait that arises during the

lifetime of an organism– acquired traits were passed on to the organism's

offspring

Lamarck

• Organisms acquire traits and then pass these traits on to their offspring

Lamarck Right and Wrong

Incorrect• Not all traits acquired get passed on

Important• Introduced Evolution/change

• Realized organisms are changing

What was Lamarck’s Theory of Evolution?

Agenda for Tuesday Nov 16th 1.Theories of Evolution: Darwin

1. Lamarck’s Giraffes2. Darwin’s Postulates

Darwin

Darwin• Quit Medical School and became a naturalist

• H.M.S. Beagle – 5 year journey to survey

• Wrote The Origin of Species

Charles Lyell

• Wrote Principle of Geology

• Uniformitarianism

• Darwin– Habitats change slowly = requires organisms to adapt

to these changes in order to survive

Galapagos Islands

• Darwin landed in the Galapagos Islands and noticed differences in animal species

• Drew and made observations while in the Galapagos

• Back in England he looked at his findings– Tortoises and Finches

Galapagos Islands

• Finches – collected 13 similar but separate species of finches– Each had a distinct bill (beak)

• Finches implied a shared recent common ancestor– Adapting to different environments

• Darwin reasoned over millions of years = many large differences

Darwin’s Theory

• Natural selection – organisms best suited for their environment reproduce more successfully than other organisms

• Over several generations organisms with favorable traits increase

Darwin’s Theories

Descent with Modification• Newer forms in the fossil record are modified

forms of older species

• All species descended from one or a few original types of life

Darwin’s Theories

Modification by Natural Selection• Influenced by Thomas Malthus– Populations have the potential of doubling and

redoubling their numbers– Human pop. have been limited by war, disease, etc.– Darwin noted most pop. have limited growth

Modification by Natural Selection• Env’t affect individual organisms in different

ways – natural selection• Adaption– traits that enhance the survival and reproductive

success– Resulting change in the genetic makeup of a

population is evolution

2 types of Adaptations

• Camouflage and mimicry

Modification by Natural Selection• An organism’s genetic contribution to the next

generation is fitness– Greater fitness = better adapted to env’t =

reproduces more successfully

• Favorable traits give organisms an adaptive advantage

• Environment “selects” traits – Favorable traits depend on demands of env’t

4 Postulates

Postulate 1

• Postulate 1 – Variation within a population

Postulate 2

• Traits are inherited/passed on

Postulate 3

• More offspring are produced than can survive

Postulate 4

• Individuals with advantages traits survive

Summary of Darwin

• Inherit traits

• Natural Selection – organisms best suited/best adapted to the environment survive and reproduce– Adaptations

What is Natural Selection?

Agenda for Wednesday Nov 17th 1.Lamarck’s Giraffes Coloring2.Darwin’s Postulates

What are Darwin’s Postulates of Evolution?

Agenda for Thursday Nov 18th 1.Go over Postulates Worksheet2.Lab3.Rat Island Evolution

Agenda for Friday Nov 19th 1.Quiz2.Galapagos Islands Video