During Darwin (book)

Question 1

Two major theories of the origin of species

Answer 1

1. descent with modification
2. natural selection

Question 2

• holds that all species, living and extinct, have descended, without interruption from one or a few original forms of life
• species that diverge from a common ancestor are at first very similar but accumulate differences over great spans of time, so that they may come to differ radically from one another

Answer 2

descent with modification

Question 3

• frequence of a variant form increases within a population from generation to generation
• fitter individuals differ only slightly from the norm of the population, but that a feature such as body size gradually evolves to become more and more different because new, slightly more extreme, advantageous variants continue to arise

Answer 3

natural selection

Question 4

Five distinct compnents of Darwin’s theory

Answer 4

1. evolution
2. common descent
3. gradualism
4. populational change
5. natural selection

Question 5

simple proposition that the characteristics of organisms change over time

Answer 5

evolution

Question 6

species had diverged from common ancestors and that species could be portrayed as one great family tree representing actual ancestry

Answer 6

common descent

Question 7

Darwin’s proposition that the differences between even radically different organisms have evolved by small steps through intermediate forms, not by leaps (saltations)

Answer 7

gradualism

Question 8

abrupt evolutionary change; sudden large-scale mutation

Answer 8

saltations

Question 9

Darwin’s hypothesis that evolution occurs by changes in the proportions (frequencies) of different variant kinds of individuals within a population

Answer 9

populational change

Question 10

Darwin’s brilliant hypothesis, independently conceived by Wallace, that accounts for adaptations, features that appear “designed” to fit organisms to their environment

Answer 10

natural selection

Question 11

belief that variation should decrease, not increase

Answer 11

blending inheritance

Question 12

proposed that inheritance is not based on blending fluids, but on particles (genes) that pass unaltered from generation to generation – so that variation can persist

Answer 12

theory of particulate inheritance