Chapter 18: Evolution And Origin Of Species

Question 1

What is evolution?

Answer 1

Change in organisms throughout Earths history

“Decent with modification”

Question 2

George Cuvier

Answer 2

(1769-1872)
Fossils
- Rock strata

Question 3

James Hutton

Answer 3

(1726-1797)

• Gradual change in geological features
• Friend of Darwin

Question 4

Charles Lyell

Answer 4

(1797-1875)

• Father of modern geology
• Uniformitarianism
• Principles of geology (1830)

Question 5

Erasmus Darwin

Answer 5

• Philosopher
• “forms minute”
• The temple of nature (1802)

Question 6

Lamarck

Answer 6

(1744-1829)

• Linked evolution to adaptation
• “use it or lose it”
• Inheritance of acquired characteristics

Question 7

Darwins Voyage

Answer 7

Charles Darwins voyage

• naturalist
• collected plants, wildlife, and fossils
• Adaptations?
• studied geology

Question 8

Charles Darwin

Answer 8

Studied geology
- Found evidence for Lyells uniformity

 Evolutionary Theory (1859)
- Alfred Wallace also helped 

Origin of Species (1859)

Question 9

Darwins Theory

Answer 9

1. Decent with modification: common ancestor / extinction is common
2. Natural Selection: Mechanism for evolution
   - heritable variation in most species.
   - all species produce more offspring then environment can support.

He inferred

• unequal reproductive success among individuals. “Best traits”
• Favorable traits accumulate over time, matching species to environment. (New species)

Question 10

Not explained in Darwins Theory

Answer 10

1. Origin of life
2. How variation occurs
3. How inheritance works
4. Why variation exists
5. “Sudden” changes in fossil records
6. Source of totally “new” characteristics

Question 11

Homology

Answer 11

Forms related by common ancestors

- Like wings, arms

Question 12

Vestigial Structures

Answer 12

• Remnants of ancestral structures with no present adaptive functions.

Question 13

Converge

Answer 13

• Unrelated species have similar adaptations (analogous structures).
• Converging evolution

Question 14

What is a Theory?

Answer 14

A scientific theory is broad, well-supported, and explained well.

Question 15

Ways to define Species

Answer 15

1. Morphological species: smallest set of organisms that look alike.
2. Ecological species: Different microorganisms.
3. Phylogenetic species: smallest distinct set of organisms.

Question 16

Prezygotic Barriers

Answer 16

• Habitat Isolation
• Temporal Isolation (not all fertile at same time)
• Behavioral Isolation (dancing)
• Mechanical Isolation (physically can’t mate)
• Gametic isolation (different receptors)

Question 17

Postzygotic Barriers

Answer 17

After zygote is formed

• Reduced hybrid viability: embryo does not develop
• Reduced hybrid fertility: hybrid in sterile
• Hybrid breakdown: 2nd gen are sterile.

Question 18

Speciation and Evolution

Answer 18

• Speciation increases diversity of life
• Microevolution alone does not make new species
• Patterns of speciation (gradual)
• “Punctuated equilibrium” (rapid)

Question 19

Allopatric

Answer 19

Barrier
- causes species to be genetically isolated, causing diverging

Hybrid zones may occur

Adaptive Radiation: Darwins Finches
- 1 bird, 13 species

Question 20

Sympatric Seperation

Answer 20

No barrier

• Habitual differentiation
• Mostly occurs in plants

Cell division error: autopolyploidy