Chapter 14 The Origin of Species

Question 1

Macroevolution

Answer 1

the study of major biological changes seen in the fossil record

Question 2

speciation

Answer 2

when changes accumulate to produce a completely distinct group of organisms

Question 3

According to the _____________, a species is a group of members in a population with the potential to interbread and produce fertile offspring

Answer 3

Biological Species Concept

Question 4

hybrids

Answer 4

the offspring of two clearly distinct species that have interbred (ex. grizzly bear + polar bear = grolar bear)

Question 5

ecological species concept

Answer 5

identifies species in terms of their ecological niche, looking at their role in the community
ex. two species may be similar in appearance but distinguishable based on what they eat or where they live

Question 6

Phylogenetic Species Concept

Answer 6

defines a species as the smallest group of individuals that share a common ancestor, forming a branch on an evolutionary tree

Question 7

Biologist trace the phylogenetic history of a species by comparing its

Answer 7

DNA sequences

Question 8

MORPHOLOGICAL SPECIES CONCEPT

Answer 8

alternate way of defining species using physical traits, shape, size, or other features.
can be applied to asexual organisms & fossils

Question 9

Reproductive barriers

Answer 9

prevent interbreeding and establish different species.

serves to isolate the gene pools of species

Question 10

Prezygotic Barriers

Answer 10

something that prevents mating from occurring

Question 11

Postzygotic Barriers

Answer 11

something that happens after conception to prevent the process from continuing

Question 12

5 different prezygotic barriers

Answer 12

Behavioral isolation: behavior must be correct for mating to occur (Blue-footed Boobie Bird ritual dance)
mechanical isolation: structural differences prevent genitals from coming into contact with the other (snails)
temporal isolation: mating & fertilization occur in different seasons
habitat isolation: live in different habitats and do not interact (water/land snakes)
Gametic isolation: female and male gametes fail to unite in fertilization.

Question 13

3 different postzygotic barriers

Answer 13

Reduce hybrid viability: most offspring do not survive
Reduce hybrid fertility: offspring are vigorous yet sterile
Hybrid breakdown: 1st generation are viable and fertile but their offsprings are usually sterile

Question 14

2 main modes of speciation

Answer 14

Allopatric speciation & Sympatic Speciation

Question 15

Allopatric Speciation

Answer 15

geographic isolation may cause a population to become genetically unique as its gene pool is changed by natural selection, genetic drift, or mutation (grand canyon squirrels). Geographic isolation may cause a population to develop reproductive barriers as a by-product of a population adapting to different environments

Question 16

Sympatric Speciation

Answer 16

occurs if a mutation creates a reproductive barrier between parents and offspring

Question 17

polyploidy

Answer 17

multiple number of chromosomes

Question 18

if a parent cell fails to divide after DNA replication occurs, chromosomes duplicate, then

Answer 18

Self-fertilization may result in a plant with a different number of chromosomes.

Question 19

adaptive radiation

Answer 19

the evolution of many diverse species from a common ancestor

Question 20

gradualism

Answer 20

explaining how a new species evolved through the gradual accumulation of changes brought about by natural selection

Question 21

punctuated equilibrium model

Answer 21

contrasting model to macroevolution

Question 22

punctuated equilibrium model proposes that species diverge in

Answer 22

spurts of relatively rapid changes as a population diverge from the ancestral populations, with little or no change occurring from the remainder of the species existence

Question 23

Punctuated model

Answer 23

long periods of little change or equilibrium punctuated by abrupt episodes of speculation

Question 24

Gradualist model

Answer 24

slow gradual changes over time