Chapter 22

Question 1

Speciation

Answer 1

The process by which one species splits into two or more species

Question 2

Micro and macro evolution

Answer 2

Changes over time in allele frequencies in a population

The broad pattern of evolution above the species level

Question 3

Reproductive isolation

Answer 3

The existence of biological factors that impede members of the two species from interbreeding to produce viable, fertile offspring

Question 4

Hybrids

Answer 4

Offspring that results from an interspecific mating

Question 5

Pre-zygotic barriers

Answer 5

Block fertilization from occurring (gametes don’t meet and fuse)

• temporal isolation (mates at different times of year)
• behavioural isolation (courtship displays vary)
• mechanical isolation (genital openings cannot align)

Question 6

Post-zygotic barriers

Answer 6

Zygote failed yo develop into mature, fertile adult

• developmental errors reduce survival
• problems after birth causing infertility or descremase survival

Question 7

Morphological vs. Biological vs. Phylogenetic species concept

Answer 7

Distinguishes species by body shape

Distinguished species by producing fertile offspring

Distinguishes species as the smallest group of individuals that share common ancestry

Question 8

Allopatric speciation

Answer 8

Gene flow is interrupted when a population is divided into geographically isolated sub populations

Ex: a lake become two separate lakes

Question 9

Sympatric speciation

Answer 9

A subset of a population forms a new species without geographical separation

• polyploidy
• habitat differentiation
• sexual selection

Question 10

Polyploidy

Answer 10

Extra sets of chromosomes which is more common in plants

Ex: strawberries

Question 11

Auto polyploidy

Answer 11

An individual that has more than two sets of chromosomes that are all derived from a single parent

(Mitosis or meiosis error)

Question 12

Allopolyploidy

Answer 12

A fertile individual that has more than two sets of chromosomes sets as a result of two different species interbreeding and combining chromosomes
-fertile when mating but cannot interbreed with parent species

Question 13

Hybrid zone

Answer 13

A region in which members of different species meet and mate, producing at least some offspring of mixed ancestry

Question 14

Reinforcement

Answer 14

Hybrids often are less fit than parents. In this case, natural selection should strengthen presumptive barriers to reproduction, reducing formation of unfit hybrids.

Question 15

Fusion

Answer 15

Barriers to reproduction may be weak when two species meet in hybrid zone. So much gene flow may occur that reproductive barriers weaken further and gene pools of two species become more alike. (Become one species again)

Question 16

Stability

Answer 16

Many hybrid zones are stable and hybrids continue to be produced. Sometimes hybrids survive and reproduce better than parent species

Question 17

Punctuated equilibra

Answer 17

In the fossil record, periods of long length of apparent stasis in which a species undergoes little or no morphological change. Interrupted by relatively brief periods of sudden change

Question 18

Introgression

Answer 18

Gradual combination of two species into one