8/28 macroevolution

Question 1

Changes in the gene pool (aka microevolution)
are caused by:
1. ______________________
2. ______________________
3. ______________________
4. ______________________
5. ______________________

Answer 1

1. mutation
2. gene flow/ migration
3. genetic drift
4. nonrandom mating
5. natural selection

Question 2

Evolution in a genetic context:
Microevolution (small changes within a population)
can lead to BIG CHANGES (_______________________)

Answer 2

1.Macroevolution

Question 3

Evolution in a genetic context:
Macroevolution
Large phenotypic changes at or above species level
(across _______________________ of the same species)

Answer 3

1.many populations

Question 4

Macroevolution
Often major morphological changes (__________________)
* Usually _________________ of ancestral feature
ex. Acquisition of ___________
Lampreys (jawless fishes)
Sharks (jawed fish)

Answer 4

1. new features
2. modification
3. jaws

Question 5

Macroevolution
* Origin of ______________
* Origin of new lineages
* Long period of time
(but can occur rapidly)

Answer 5

1.new species

Question 6

Speciation
* Species: Latin for “kind” or “appearance”
* Speciation: process of creating ________________

• What is a species?
• Species
  – is a ________________________ level in nature
  – Each species has its own unique combination of
  genes underlying its distinctive __________________ and
  __________________________

Answer 6

1. new species
2. fundamental
3. appearance
4. behaviors

Question 7

Species Concepts:
1. Morphological Species Concept
* Individuals from same species share measureable traits that distinguish them (phenotypic differences)
* Uses diagnostic ____________________________

Answer 7

1.physical characters

Question 8

Species Concepts:
1. Morphological Species Concept
___________ with using this species concept exclusively:
* Some species (ex. European garden snail)
have so much shell variation, it would be difficult to know if they just represented ______________

• Morphology may not help to distinguish two closely related species that are
  nearly _______________ in appearance

Answer 8

1. Issues
2. one species
3. identical

Question 9

Species Concepts:
2. Biological Species Concept
* Members of different populations that can mate and produce fertile ______________ in a
____________ setting are the same species
* Issues with using this species concept exclusively:
– Not applicable to _______________ or
_________________ species
* Reproductive isolation is a central aspect of the speciation process under this concept

Answer 9

1. offspring
2. natural
3. asexual
4. extinct

Question 10

Reproductive Isolating Methods:
Prezygotic Isolating Mechanisms Prevents reproduction attempts, and make it unlikely fertilization will be successful

Reproductive Isolating Methods
1. Ecological isolation
2. Temporal isolation —–>_____ mating
3. Behavioral isolation

4. Mechanical isolation
5. Gamete isolation —–> prevent _____

Answer 10

1. prevent
2. fertilization

Question 11

1. Ecological/Habitat Isolation
   Ecological isolation
   * Species occur in the ______________ but occupy different habitats and rarely ________________ each other
   * If they live in the same place, they can’t mate with each other if they do not come in contact with one another

Answer 11

1. same area
2. encounter

Question 12

2. Temporal Isolation (prevents mating)
   Species living in same area that mate at _____________ ____________ of day or different times of the year

Answer 12

1. different times

Question 13

3. Behavioral Isolation
   (prevents mating)
   Behavioral isolation
   * When signals of one species are
   _______________________________ by another
   * Courtship rituals are critical for mating within a species, but ineffective for attracting members of other species

Answer 13

1. not recognized

Question 14

4. Mechanical Isolation
   (prevents fertilization)
   Mechanical isolation
   * Differences in _____________ make mating
   impossible
   – Difference in reproductive organs
   – Difference in sizes of organisms

Answer 14

1. physical structure

Question 15

5. Gametic Isolation
   (prevents fertilization)
   Gametic isolation
   * When individuals of different species mate but fertilization does not because of incompatibility between _________________

Answer 15

1.sperm and egg

Question 16

Reproductive Isolating Methods
Postzygotic Isolating Mechanisms Prevents hybrid offspring from developing or breeding
1. Hybrid inviability
* Fusion of gametes but fail to _______________
* Die as embryos or at ___________________
2. Hybrid sterility
(ex. mule = horse x donkey)
3. Hybrid breakdown
(second generation hybrids reduce survival or fertility)

Answer 16

1.develop
2.early age

Question 17

Modes of speciation
1. Allopatric speciation (vicariance)
* (allo=other, patria=homeland)
* Occurs when one population is geographically ____________ from other _____________________

Answer 17

1. isolated
2. populations

Question 18

1) Allopatric speciation:

1. One initial large population
2. Divided by phyiscal ___________________
3. ____________________ on both sides of the barrier and subsequent genetic differentiation
4. ______________________

Answer 18

2. barrier
3. natural selection
4. 2 species

Question 19

2) Sympatric Speciation
- (sym=together, patria=homeland)

A population develops into two or more reproductively isolated groups ______________ geographic isolation
* Disruptive selection
* Chromosomal changes
(polyploidy)

Answer 19

1. without

Question 20

3. Adaptive Radiation
   * Many new species evolve from a ____________
   ancestral species
   * Adapted to different environments and exploit
   _____________________________
   * Relatively _______________________

Answer 20

1. single
2. different niches
3. fast evolution

Question 21

3. Adaptive Radiation Promoted by:
4. New and varied niches
   - provide new ______________________________
5. Absence of interspecific competition
   - enables species to invade niches ______________
   ______________________ by others

Answer 21

1.source of resources
2.left or inhabited