#15 Evolution and Diversity

Question 1

Microevolution

Answer 1

Short time span

Change in allele frequencies within a pop

Question 2

Macroevolution

Answer 2

Long time span
Cumulative effects of micro. process
Continuum of genetic distinction

Results in:

• new species
• higher order taxa

Question 3

Biological species (concept)

Answer 3

Population(s) whose members have the potential to reproduce and produce fertile offspring

Question 4

Reproductive isolation

Answer 4

New species arise (speciation) by the formation of barriers to reproduction of fertile offspring
-occurs by microevolutionary forces

1. Prezygotic barriers
2. Postzygotic barriers

Question 5

Prezygotic barriers

Answer 5

Physically prevent mating or fertilization between species

1. Temporal isolation- different times of mating
2. Habitat isolation- different habitats
3. Behavioral isolation- little or no sexual attraction
4. Mechanical isolation- structural differences prevent copulation
5. Gamete isolation- male and/or female gametes die before uniting or fail to unite

Question 6

Postzygotic barriers

Answer 6

Prevent the development of fertile adults

1. Reduced hybrid viability- fails to develop or to reach sexual maturity (not viable)
2. Reduced hybrid fertility- fail to produce functional gametes (not fertile)
3. Hybrid breakdown- offspring of hybrids are weak or infertile

Question 7

Allopatric Speciation

Answer 7

Occurs when populations are isolated by geographic barriers

-physical separation allows pop.s to pursue own evolutionary course

Question 8

Sympatric Speciation

Answer 8

Occurs without geographic isolation

• rare in animals, common in plants (genetic errors)
• > e.g. polyploid plant- has more than two sets of chromosomes

Question 9

Adaptive radiation

Answer 9

Common ancestor introduced to new environment
-extra niche space allows room for change -> evolve to take advantage
Allows for more specification

Question 10

Macro changes

Answer 10

come about by gradual refinements

Question 11

Exaptations

Answer 11

Changes in the function of an existing structure

-may arise from changes in developmental genes

Question 12

Species diversity

Answer 12

Plants ~321,000
Insects >1,000,000 (most diverse)
Vertebrates ~ 62,000 ( ~5,500 mammals)

Question 13

Taxonomy

Answer 13

Classifying and naming organisms

-hierarchical

Question 14

Phylogeny

Answer 14

Evolutionary history of an organism

-development and diversification of organism or group

Question 15

Binomial nomenclature

Answer 15

Species name: Genus then species (both italicized)

Question 16

Systema Naturae

Answer 16

Evolutionary and recaps phylogeny

Question 17

Kingdom system

Answer 17

Prokaryotes formerly Monera the Eukaryotes (Protista, Plantae, Fungi, Animalia)

Question 18

History of life on Earth

Answer 18

4.6 billion- Earth is formed
3.5 billion- Oldest fossils preserved
2.2 billion- Oldest Eukaryote fossils
450 million- Plants and animals invade land
220 million- First dinosaurs and mammals
65 million- Dino go extinct
5.3 million- Ardipithecus
250,000- Homo sapiens

Question 19

Diversity

Answer 19

Increased over time, lineages become more complicated