Lecture 2: Theories in Evolution

Question 1

5 theories of evolution

Answer 1

1) Perpetual change
2) Common Descent
3)Multiplication of species
4) Gradualism
5) Natural Selection

Question 2

Perpetual change

Answer 2

Living organisms are not constant or immutable; they change.
Rejects creationism and supports the other 4 theories

Question 3

Common Descent

Answer 3

There is a common ancestor for all living forms (Life is like a branching tree).
Looks at common features to find relationships among groups of evolution

Question 4

Evidence of relationships among groups

Answer 4

Fossils and molecular studies

Question 5

Homologies

Answer 5

Characters derived from a common ancestor, differences come from divergent evolution

Question 6

Analogies

Answer 6

Not from a common ancestor; Independent origin.
Similarities come from convergent evolution

Question 7

Cladogram

Answer 7

Hierarchy of groups in a branching diagram, tells when groups are related and how closely

Question 8

Multiplication of species

Answer 8

An ancestral form splits into two or more derived forms, quantified by species

Question 9

4 Main concepts of species

Answer 9

A) Typological Concept
B) Biological concept
C) Evolutionary
D) Phylogenetic

Question 10

Typological Concept of Species

Answer 10

Based on morphological similarities, individuals and populations that look similar are grouped together as one species, limited by species changes and evolving

Question 11

Biological concepts of species

Answer 11

Based on similarity, niche, and the ability of individuals to interbreed and produce viable offspring
Limits: Asexual reproduction and hybrids

Question 12

Evolutionary Concept of Species

Answer 12

Based on biological concept and evidence of ancestry (common ancestor)
Limitations: the species with no ancestry info like fossils (jelly fish)

Question 13

Phylogenetic concept of species

Answer 13

Based on the evolutionary concept and any recognizable genetic variation resulting from isolation
Limitations: It is hard to judge what a recognizable variation is.

Question 14

How does speciation proceed

Answer 14

1) Spacial and temporal isolation (allopatric process)
2) Niche Speciation: (sympatric process) Coexistence in the same area
3) Mutations: Allopatric or sympatric)

Question 15

Recognition of a new species (3 Things)

Answer 15

1) an official binomial name
2) An official description (in a scientific publication)
3) An official type or preserved specimen in a collection or museum

Question 16

Gradualism

Answer 16

Change among populations and species occurs as a gradual process over a long time
Limits: Mutations? gaps in the fossil record?

Question 17

Punctuated Equilibrium

Answer 17

Eldredge and Gould: Speciation is sudden, period of fast abrupt change and periods of no change or slow change

Question 18

Natural Selection

Answer 18

• Populations are fertile
• Resources are limited, so numbers cannot rise endlessly
• Traits are hereditary (mendal) but there are no identical descendants
• Survival is always differential: only the fittest can survive and reproduce

Question 19

Adaptive Radiation

Answer 19

-Formation of various species from a common ancestral form
-If habitat changes, one original species may become multiple, like darwins finches
-Also occurs after massive extinctions