Lecture 5: Accepting Darwinism

Question 1

5 sub-theories of the origin of species

Answer 1

1. Evolution
2. Common descent
3. Multiplication of species (new species created over time from diverging of existing species)
4. Gradual phenotypic changes
5. Natural selection

Question 2

Controversies with the origin of species (5)

Answer 2

1. religious beliefs (age of the world, creation, unique position of man)
2. Essentialism, where for every species there are a set list of attributes that make it that species (ie if a bird doesn’t have feathers is it a bird?)
3. Physics envy : Many physicists and chemists do not believe biology to be a real scientific discipline as it cannot be reduced to mathematics
4. Teleology: Organisms have a specific purpose or “destiny” in mind
5. Political beliefs : (the Natzi’s hated Darwin as it went against Eugenics and teleology

Question 3

Eugenics (2)

Answer 3

-Eugenics is a movement aimed at improving the genetic composition of the human race, usually through selective breeding

-based on “predetermined genetics” - ignoring environmental contributions to phenotypes (hence why the natzis hated Darwin)

Question 4

Alternatives to natural selection (4)

Answer 4

1. Lamarckism
2. Neo - Lamarckism
3. Orthogenesis
4. Mutationism

Question 5

Lamarckism (definition and example + historical significance)

Answer 5

-Theory that organisms can pass on physical traits that they acquire in their lifetimes

-ex a giraffe passing on neck size to its offspring because it stretched its neck out reaching taller trees

-Was used in communist Russia leading by Lysenko, who used this theory to breed crops for cold tolerance. This lead to disastrous crop failures, food shortages, and starvation

Question 6

Neo-Lamarckism

Answer 6

Combines Lamarckism with natural selection

Question 7

Orthogenesis (5)

Answer 7

• The theory that mutations are directional

-mostly believed by paleontologists

-Fixed direction of change, driving evolution “forward”

-Could be used to explain extinct species

-Independent of external factors

Question 8

Mutationism (2)

Answer 8

-in the 1900’s Mendel’s work rediscovered spontaneous variants defined as “mutants”

-believed that mutations were the driving force of evolution

Question 9

Foundations for the consensus of Darwinism

Answer 9

-revised calculations of the earths age

-Darwinism combined with mendalean genetics

-contributions from other geneticists and naturalists

-Lead to the “second Darwin revolution and the creation of neo-Darwinism”