Chapter 22

Question 1

Speciation

Answer 1

Origin of new spp is at focal point of evolutionary theory

Question 2

Evolutionary Theory

Answer 2

must explain how new spp originate and how populations evolve

Question 3

Microevolution

Answer 3

Consist of changes in allele freq in a pop over time

Question 4

Macroevolution

Answer 4

Refers to broad patterns of evolutionary change above spp level

Question 5

Allopatric

Answer 5

Species live in different areas (disjunct)

Question 6

Sympatric

Answer 6

Species inhabit the same area but remain distinct. Overlaps

Question 7

Morphogical Spp concept

Answer 7

If a pop differs in a number of physical characters, they belong to a different species
Problem - close geographically but different color, color can confuse morphology

Question 8

Biological Species concept

Answer 8

One or more pop whose members interbreed with each other to reproduce fertile offspring
&
Do not interbreed with members of other pop
Cannot be applied to fossils or asexual organisms.
Emphasizes absence of gene flow

Question 9

Reproductive isolation
6 mechanisms

Answer 9

The existence of biological factors (barriers) that impede two species from producing viable, fertile offspring.
Prezygotic isolation
Ecological - spp occur in the same area, but occupy different habitats, rare encounters
Behavioral - Spp differ in their mating rituals (dance, sound, call)
Temporal - spp reproduce in different seasons or times of day
Mechanical - structural differences between spp prevent mating
Prevention of gamete fusion - gametes of one spp function poorly with gametes of other spp or in reproductive tracts.
Postzygotic isolation
Hybrid inviability or infertility- Hybrid embryos do not develop properly. Hybrid adults do not survive in nature or are sterile.

Question 10

Prezygotic barriers

Answer 10

Block fertilization from occurring by impeding diff spp from attempting to mate. Prevent successful completion of mating, or hinder fertilization if mating is successful.

Question 11

Postzygotic barriers

Answer 11

prevent the hybrid zygote from developing into a viable fertile adult, reduce hybrid viability, fertility, or hybrid breakdown.

Question 12

Speciation 2 step process

Answer 12

1 identical populations must diverge in some character(s)
2 Reproductive isolation mechanism(s) must evolve to maintain the differene(s)

Question 13

Polyploidy

Answer 13

Can duplicate and possess 2 entire copies of genome without consequences. Overtime genes become modified or nonfunctional and they become different species.
Allopolyploidy
Autopolyploidy

Question 14

Allopolyploidy

Answer 14

Mitosis - cell repair regen, clones, diploid
After two incompatibly spp mate (2 chroms and 3 chroms) they duplicate chromosomes during mitosis to have 2n=10. Gametes have n=5 and if reproduce with another could create a new spp

Question 15

Autopolyploidy

Answer 15

Meiosis - gamete production
During meiosis I chromosomes don’t separate properly and number of chromosomes stays the same in gamete (instead of 1/2) and if reproduce with another could create a new spp

Question 16

Adaptive radiation and biological diversity

Answer 16

Adaptive radiation is the rapid diversification of one ancestral spp into many different spp. Takes advantage of different parts of environment (Niches)

Question 17

Two models for pace of evolution

Answer 17

Gradualism - long slow change from 1 spp to 2 spp.
Punctuated equilibrium - spp stays the same until rapid evolution in short spurts, can become multiple spp.