Ch 13 How Populations Evolve

Question 1

Darwin’s Hypothesis

Answer 1

• present day species are the descendants of ancient ancestors that they still resemble in some ways
• change occurs as a result of “descent with modification” with natural selection as its mechanism

Question 2

natural selection

Answer 2

is a process in which organisms with certain inherited characteristics are more likely to survive and reproduce than individuals with other characteristics

Question 3

population

Answer 3

a group of individuals of the same species living in the same place at the same time

Question 4

evolutionary adaptation

Answer 4

a populations increase in frequency of traits suited to the environment

Question 5

evolution

Answer 5

• a change in the genetic composition of a population over time
• on a grander scale, the entire biological history, from the earliest microbes to the enormous diversity of organisms that live on earth today

Question 6

natural selection leads to

Answer 6

• a population changing over generations and

- evolutionary adaptation

Question 7

evidence of evolution

Answer 7

1. fossil record
2. biogeography
3. comparative anatomy
4. comparative embryology
5. molecular biology

Question 8

fossils are

Answer 8

imprints or remains or organisms that lived in the past, often found in sedimentary rocks

Question 9

the fossil record

Answer 9

• is the ordered sequence of fossils as they appear in rock layers
• reveals the appearance of organisms in a historical sequence

Question 10

transitional fossils include evidence that

Answer 10

• birds descended from one branch of dinosaurs

- whales descended from four-legged land mammals

Question 11

biogeography

Answer 11

the study of the geographic distribution of species

Question 12

comparative anatomy

Answer 12

• is the comparison of body structure between different species
• evolution is a remodeling process ancestral structures become modified for new functions

Question 13

homology

Answer 13

• the similarity in structures due to common ancestry

- illustrated by the remodeling of the pattern of bones forming forelimbs of mammals for different functions

Question 14

the hereditary background of an organism is documented in

Answer 14

• its DNA

- the proteins encoded in the DNA

Question 15

evolutionary relationships among species can be determined by comparing

Answer 15

-genes and proteins of different organisms

Question 16

Darwin based his theory on two key observations

Answer 16

1. all species tend to produce excessive numbers of offspring
2. organisms vary and much of this variation is heritable

Question 17

observation 1: overproduction and competition

Answer 17

• all species have the potential to produce many more offspring than the environment can support
• this leads to inevitable competition among individuals

Question 18

observation 2: individual variation

Answer 18

• variation exists among individuals in a population

- much of this variation is heritable

Question 19

interference

Answer 19

unequal reproductive success

Question 20

examples of natural selection include

Answer 20

• pesticide-resistant insects
• antibiotic -resistant bacteria
• drug-resistant strains of HIV