Ch. 14 The Origin of Species

Question 1

Taxonomy

Answer 1

The branch of biology concerned with identifying, naming, and classifying diverse forms of life

Question 2

Biological species concept

Answer 2

A species consists of organisms so smilier in structure/function that they can reproduce fertile offspring.
- sexual species

Question 3

What does failure of sexual reproduction result in?

Answer 3

1) Prevention of Gene flow

2) Is the gap between species

Question 4

In what situations does biological species concept not work? Why?

Answer 4

Extinct forms of life and asexual reproducers.

- no gene flow

Question 5

Speciation

Answer 5

The evolution of a new species

Question 6

Evolutionary species concept

Answer 6

The definition of a species as a cluster of recognizably distinct organisms that represent a lineage of descent

• may be recognized by genotypic/phenotypic features
• ex. DNA sequence and body structures

Evolutionary history rather than reproductive ability

• represent a genealogy
• applies to sexual, asexual, and extinct

Question 7

What is classification based on?

Answer 7

Observable and measurable phenotypic traits and DNA analysis

Question 8

What did Kar von Linne (Carolus Linnaeus) do?

Answer 8

Binomial nomenclature “two name system of naming”

- genus + species

Question 9

What is a species?

Answer 9

Genetically distinct group of organisms that share a common gene pool

Question 10

What are the 3 (plus 1) factors of a species?

Answer 10

1) Anatomy (Structure)
2) Physiology (Function)
3) Behavior (Acts)

Plus reproduction

Question 11

What are the 3 criteria to classification?

Answer 11

1) Observable and measurable phenotypic traits
2) Ability to mate and produce fertile offspring
3) DNA & Protein analysis of genotype

Question 12

What are 2 types of barriers that prevent inbreeding?

Answer 12

1) Geographical
- physically isolate
2) Reproductive
- biologically isolate

Question 13

What are the two types of reproductive barriers?

Answer 13

1) Prezygotic
- occurs before fertilization
2) Postzygotic
- prevents the development of fertile adults

Question 14

What are the 5 types of pre zygotic reproductive barriers?

Answer 14

1) Temporal Isolation
- same general area, different mating time
2) Habitat
- same area but not specific part
3) Behavioral
- little or no sexual attraction
4) Mechanical
- sex organs are not compatible
5) Gametic
- gametes do not unite to form a zygote

Question 15

What are 3 types of post zygotic reproductive barriers?

Answer 15

1) Hybrid Inviability
- hybrid is too frail, fails to develop or reach sexual maturity
2) Hybrid Sterility
- sterile organisms
3) Hybrid Breakdown
- first generations are okay, but then their offsprings are infertile

Question 16

What do reproductive barriers form?

Answer 16

Reproductive barriers form boundaries around closely related species to prevent species from losing their identities.

Question 17

What is the key event of speciation?

Answer 17

Separation of a population from other populations of same species
- gene pool is isolated

Question 18

Allopatric Speciation

Answer 18

The formation of a new species as a result of an ancestral population’s becoming isolated by a geographical barrier

• depends on the ability of organisms to move about
• creates opportunity for speciation (not guaranteed)
• reestablishes the reproductive barriers between the two populations
• small isolated populations

Question 19

Adaptive radiation

Answer 19

The emergence of numerous species from a common ancestor introduced to new/diverse environments

Question 20

Sympatric speciation

Answer 20

The formation of a new species as a result of a genetic change that produces a reproductive barrier between the changed population (mutants) and the parent population

• ex. plant evolution
• polyploid cells

Question 21

Polyploid cells

Answer 21

A cell with more than 2 complete sets of chromosomes

- meiosis fails, mitosis occurs –> diploid gametes

Question 22

What are the 2 events required of sympatric speciation?

Answer 22

1) Hybridization of 2 parent species

2) Failure of meiosis in resultant hybrid

Question 23

Gradualist model

Answer 23

The view that evolution occurs as a result of populations becoming isolated from common ancestral stock and gradually becoming genetically unique as they are adapted by natural selection to their local environment
- Darwin’s view of origin of species

Question 24

What are the 2 patterns of gradualist model?

Answer 24

1) Divergence of a new lineage

2) Evolutionary changes with unbranched linage

Question 25

Punctuated Equilibrium

Answer 25

The idea that speciation occurs in spurts followed by long periods of little change

• abrupt divergence of new lineages
• no speciation within unbranched lineage