module 6

Question 1

what is macroevolution?

Answer 1

above the species level (gives us new species)

Question 2

what is microevolution?

Answer 2

below the species level (all evolution has been micro thus far)

Question 3

what is a biological species defined as?

Answer 3

group of naturally breeding populations that are reproductively isolated from other groups

Question 4

what is speciation?

Answer 4

occurs when one species splits into 2
- involves reproductive isolating mechanism

Question 5

what is a reproductive isolating mechanism? what does it lead to?

Answer 5

anything that prevents 2 populations from breeding effectively
- leads to speciation

Question 6

What are the two types of reproductive isolating mechanisms?

Answer 6

• extrinsic: factors producing geographic isolation
• intrinsic: factors unrelated to geographic isolation

Question 7

what are the 2 kinds of intrinsic reproductive isolating mechanisms?

Answer 7

• prezygotic: zygote never forms
• postzygotic: zygote forms but may have mutation that will cause it to die later

Question 8

What is the relationship between natural selection & population variability?

Answer 8

the rate of evolutionary change is directly proportional to the degree of variability in a population
(e.g lots of variation –> lots of alleles)

Question 9

What is the corollary natural selection principle?

Answer 9

the fate of all evolutionary lineages is extinction

Question 10

what is anagenesis? what theory of evolutionary change does this support?

Answer 10

change in a species over a long period of time (supports gradualism theory of evol. change)

Question 11

What is cladogenesis? what theory of evolutionary change does it support?

Answer 11

sudden split results in formation of 2 species from 1 species (supports punctuated theory of evol. change)

Question 12

what is phyletic gradualism?

Answer 12

small changes occur over time & accumulate over a long period of time (anagenic change)

Question 13

what is punctuated equilibrium?

Answer 13

evolution goes through long periods where nothing changes, but sudden changes occur (cladogenic change)

Question 14

what is adaptive radiation?

Answer 14

the rapid expansion/diversification of a group of organisms as they adapt to newly available ecological space

Question 15

what is a generalized organism?

Answer 15

able to live in wide range of habitats

Question 16

what is a specialized organism?

Answer 16

has defined ecological niche (way of interacting with environment)

Question 17

what is an overgeneralized organism?

Answer 17

leads to extinction when environment changes bc they can’t adapt well

Question 18

what is the purpose of phylogenetic relationships?

Answer 18

• determines who is related to whom & how closely
• uses anatomical similarities

Question 19

what is evolutionary homology?

Answer 19

-similarities between organisms due to common ancestry
- structure might have different function

Question 20

what is evolutionary analogy?

Answer 20

similarities between 2 organisms that are INDEPENDENTLY EVOLVED
- coincidental
- same function

Question 21

what are two types of analogy?

Answer 21

• convergence: similarities between 2 UNRELATED organisms
• parallelism: similarities between 2 RELATED organisms (more recent common ancestor

Question 22

what is a primitive/ancestral trait?

Answer 22

trait retained in its ancestral form

Question 23

what is a derived trait?

Answer 23

change in ancestral form of a trait (including losing a trait)

Question 24

what are shared derived traits?

Answer 24

derived trait shown ACROSS SPECIES (e.g. cloven hoof found in cows, goats, deer)