Chapter 24

Question 1

Darwin discovered

Answer 1

plants and animals in the galapagos island that didn’t exist anywhere else on earth.

Question 2

Speciation

Answer 2

the origin of new species, is the focal point of evolutionary theory

Question 3

Microevolution

Answer 3

consists of changes in genetic alleles frequency in a population over time.

Question 4

Macroevolution

Answer 4

refers to broad patterns of evolutionary change above the species level.

• origin of new groups
• cumulative effect of many speciation and extinction time

Question 5

Species Latin word

Answer 5

“kind” or “appearance”

Question 6

biological species concept

Answer 6

states that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring, they do not breed successfully with members with another population.

Question 7

Reproductive Isolation

Answer 7

is the existence of another biological factors (barriers) that impede 2 species from producing viable, fertile offspring.

Question 8

Hybrids

Answer 8

are the offspring of crosses between different species

• a sterile mule ( a hybrid product of horse+ donkey)

Question 9

pre or post zygotic barriers

Answer 9

Reproductive isolation can be classified by whether

factors act before or after fertilization

Question 10

Prezygotic barriers

Answer 10

block fertilization from occurring by

• Impeding different species from attempting to mate
• Preventing the successful completion of mating
• Hindering fertilization if mating is successful

Question 11

habitat isolation

Answer 11

species encounter each other rarely, or not at all, because they occupy different habitats, even though not isolated by physical barriers

Question 12

temporal isolation

Answer 12

Species that breed at different times of the day, different seasons, or different years cannot mix their gametes

Question 13

behavioral isolation

Answer 13

Courtship rituals & other behaviors

unique to a species are effective barriers to mating

Question 14

mechanical isolation

Answer 14

Morphological/anatomical differences prevent successful completion of mating

Question 15

Gametic Isolation:

Answer 15

Sperm of 1 species may not be able to fertilize eggs of another species

Question 16

Postzygotic barriers

Answer 16

prevent the hybrid zygote from developing into a viable, fertile adult

Question 17

Reduced hybrid viability:

Answer 17

Genes of the different parent species may interact and impair the hybrid’s development or survival in its environment
-Hybrid offspring don’t complete development or if they do, are “frail”

Question 18

Reduced hybrid fertility:

Answer 18

Even if hybrids are vigorous, they may be sterile.

Ex. a robust mule still can’t mate with a donkey or horse

Question 19

Hybrid breakdown

Answer 19

Some 1st generation hybrids are fertile, but when they mate with each other or with either parent species, offspring of the next generation are feeble
or sterile

Question 20

Limitations of the Biological Species Concept

Answer 20

It emphasizes absence of gene flow. However, gene flow (transfer of genes/alleles from 1 population to another) can occur between distinct species
- Ex. Brown/grizzly bears & polar bears can mate to produce “grolar bears”

Question 21

Morphological species concept

Answer 21

defines a species by structural features

Question 22

Ecological species concept

Answer 22

views a species in terms of its ecological niche (sum of how members of the species interact with the nonliving & living parts of their environment)

Question 23

Phylogenetic species concept

Answer 23

defines a species as the smallest group of individuals on a phylogenetic tree

Question 24

Speciation can take place with or without geographic separation

Answer 24

-Allopatric speciation

􏰀- Sympatric speciation

Question 25

allopatric speciation

Answer 25

gene flow is interrupted or reduced when a population is divided into geographically isolated subpopulations

Question 26

barrier

Answer 26

depends on the ability of a population to disperse

Question 27

Separate populations may evolve independently through

Answer 27

DNA mutation, natural selection & genetic drift

Question 28

mosquitofish

Answer 28

have evolved reproductive isolation as a result of selection under different levels of predation

Question 29

sympatric speciation

Answer 29

speciation takes place in

geographically overlapping populations

Question 30

Habitat differentiation

Answer 30

Sympatric speciation can also result from

the appearance of new ecological niches

Question 31

Polyploidy

Answer 31

autopolyploid & allopolyploid

Question 32

Sexual selection

Answer 32

Ex. Lake Victoria (East Africa) mate choice based on male

coloration in cichlid fish which serves as a reproductive barrier

Question 33

Polyploidy is the

Answer 33

presence of extra sets of chromosomes due to accidents/mistakes that occur during cell division
-common in plants than in animals

Question 34

Many important crops

Answer 34

oats, cotton, potatoes, tobacco, and wheat) are polyploids