Ecology/Evolution (A1, A2

Observations that led to new thinking about evolution

1) species are well suited to their environment

2) species are not uniformly distributed (biogeography)

3) organisms differ but also have similarities

4) things that used to exist no longer exist (extinction/fossils)

Natural theology

the former study of nature as a way to understand what is going on in the mind of the creator

Catastrophism

theory that the earth was shaped and changed by sudden and large-scale catastrophic events

Uniformitarianism

the processes and forces acting today are the same as those in the past

Gradualism

idea that small incremental changes accumulate over time (slow processes given enough time)

Which 2 people came to the idea of Natural selection?

Charles Darwin and Alfred Russell Wallace

How did inventions like the microscope and telescope bring about new thinking?

Originally assumed that if we couldn’t see it then it didn’t exist, but these inventions changed our thinking about scale. It revealed existence beyond our previous comprehension and led to a desire for natural explanations

What is the best estimate for how old the Earth is?

4.6 billion years old (dinosaurs appeared approx. 230 million years ago)

Darwin’s two major insights

common ancestry and natural selection

Common ancestry

idea that living species have ancestors and have ancestors in common

Homologous traits

traits shared by organisms with a common ancestor

Natural Selection

mechanism for how organisms have come to be numerous, diversified and well adapted

Darwin’s ideas predict intermediate forms

We do see intermediate forms (amphibians, tiktaalik, archaeopteryx)

How could intermediate stages of complex traits be functional enough to be beneficial?

Intermediate stages don’t need to be perfect or function in the same way as subsequent forms. They just need to increase the fitness of the organisms that possess those traits at that time. (ex: eyes, feathers)

4 necessary and sufficient conditions for natural selection

1) individuals in a population vary

2) these variations are inheritable/genetic

3) in every generation, some individuals produce more offspring than others

4) differences in offspring production are related to the variation among individuals

Fitness

refers to being fit for your conditions

higher fitness refers to higher genetic representation in future generations