Ex1 Study Guide

Question 1

What is Aristotle’s scala naturae?

Answer 1

A classification system arranging species on a ladder of increasing complexity

This concept aligns with the idea that species are fixed and perfectly designed, influenced by the Old Testament.

Question 2

Who is known for advocating catastrophism?

Answer 2

Georges Cuvier

Cuvier speculated that each boundary between strata represents a catastrophe.

Question 3

What does Charles Lyell’s uniformitarianism suggest?

Answer 3

Changes in Earth’s surface result from slow and continuous actions still operating today

This view strongly influenced Darwin’s thinking.

Question 4

What hypothesis did Lamarck propose regarding species evolution?

Answer 4

Species evolve through use/disuse of body parts and inheritance of acquired characteristics.

Question 5

What is natural selection?

Answer 5

The process where individuals with favorable inherited traits are more likely to survive and reproduce

Darwin’s theory includes two observations and two inferences.

Question 6

What are Darwin’s two observations regarding natural selection?

Answer 6

• Members of a population vary in inherited traits
• All species can produce more offspring than the environment can support.

Question 7

What are the two inferences drawn by Darwin from his observations?

Answer 7

• Individuals with favorable traits tend to reproduce more
• Unequal ability to survive and reproduce leads to accumulation of favorable traits.

Question 8

Define ‘descent with modification’.

Answer 8

The concept that all organisms are related through descent from an ancestor that lived in the past.

Question 9

What is artificial selection?

Answer 9

The process by which humans select and breed individuals with desired traits.

Question 10

What significant event did Darwin witness during his voyage on the HMS Beagle?

Answer 10

An earthquake and the movement of strata on earth.

Question 11

What is the difference between individuals and populations in terms of selection?

Answer 11

Individuals do not evolve; populations evolve.

Question 12

What are vestigial structures?

Answer 12

Remnants of features that served important functions in the organism’s ancestors.

Question 13

What distinguishes homology from analogy?

Answer 13

Homology refers to similarity resulting from common ancestry, while analogy refers to similarities due to convergent evolution.

Question 14

What is biogeography?

Answer 14

The geographic distribution of species.

Question 15

What is the significance of continental drift and Pangea in evolution?

Answer 15

Pangea was a supercontinent that separated, affecting species distribution and evolution.

Question 16

Differentiate between microevolution and macroevolution.

Answer 16

• Microevolution: change in allele frequency in a population over generations
• Macroevolution: broad patterns of evolutionary change above the species level.

Question 17

What is average heterozygosity?

Answer 17

The average percent of loci that are heterozygous in a population.

Question 18

Define phenotypic plasticity.

Answer 18

Variation in phenotype that is not due to genotypic differences among individuals.

Question 19

What is Hardy-Weinberg equilibrium?

Answer 19

A theoretical model describing a population that is not evolving.

Question 20

List the conditions for Hardy-Weinberg equilibrium.

Answer 20

• No mutations
• Random mating
• No natural selection
• Extremely large population size
• No gene flow.

Question 21

What is the Hardy-Weinberg equation?

Answer 21

p² + 2pq + q² = 1.

Question 22

What is genetic drift?

Answer 22

Chance events cause allele frequencies to fluctuate unpredictably from generation to generation.

Question 23

What is the founder effect?

Answer 23

A few individuals become isolated from a larger population, leading to different allele frequencies.

Question 24

What is the bottleneck effect?

Answer 24

A sudden reduction in population size due to environmental changes, affecting allele frequencies.

Question 25

Define gene flow.

Answer 25

The movement of alleles among populations, which can reduce differences between populations.

Question 26

What is sexual selection?

Answer 26

Natural selection for mating success, which can lead to sexual dimorphism.

Question 27

What is sexual dimorphism?

Answer 27

The difference in physical characteristics between males and females of the same species.

Question 28

What is the biological species concept?

Answer 28

A species is a group of populations whose members can interbreed in nature and produce viable, fertile offspring.

Question 29

What are prezygotic barriers?

Answer 29

Factors that prevent mating or fertilization between species.

Question 30

What are postzygotic barriers?

Answer 30

Factors that prevent hybrid offspring from developing into viable, fertile adults.

Question 31

What is allopatric speciation?

Answer 31

Speciation that occurs when populations are geographically isolated from one another.

Question 32

What is sympatric speciation?

Answer 32

Speciation that occurs without geographic isolation.

Question 33

What is punctuated equilibrium?

Answer 33

The theory that species evolve during short periods of rapid change interspersed with long periods of stability.

Question 34

What is speciation genetics?

Answer 34

The study of the genetic changes that lead to the formation of new species.

Question 35

What is roevolution?

Answer 35

The evolutionary change above the species level ## Footnote Broad patterns of evolutionary change over long time spans & formation of new groups.

Question 36

Define the Biological Species Concept.

Answer 36

A species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring ## Footnote Emphasis on reproductive isolation.

Question 37

What is the significance of reproductive isolation?

Answer 37

It impedes two species from producing viable, fertile offspring ## Footnote Ongoing exchange of alleles between populations holds them together.

Question 38

What are hybrids?

Answer 38

Offspring of interspecific mating ## Footnote Can be classified by whether factors act before or after fertilization.

Question 39

What are Prezygotic Barriers?

Answer 39

Factors that block fertilization from occurring ## Footnote They prevent interspecies reproduction from occurring.

Question 40

What is habitat isolation?

Answer 40

Differences in where species live, preventing them from encountering one another.

Question 41

What is temporal isolation?

Answer 41

Differences in mating cycles.

Question 42

What does behavioral isolation refer to?

Answer 42

Distinct differences in courtship behaviours/traditions that aren't noticed/recognized by females of different species.

Question 43

What is mechanical isolation?

Answer 43

Physical differences in genitalia preventing successful mating.

Question 44

Define gametic isolation.

Answer 44

When sperm and egg of different species cannot fuse to form a zygote.

Question 45

What are Postzygotic barriers?

Answer 45

Factors that reduce survival among hybrid embryos.

Question 46

What is reduced hybrid viability?

Answer 46

Within areas where two species can breed, resulting embryos often do not survive or will have major morphological anomalies.

Question 47

What does reduced hybrid fertility mean?

Answer 47

Offspring of hybrids will be sterile ## Footnote Example: female horse mating with male donkey produces mules, which cannot reproduce.

Question 48

What is hybrid breakdown?

Answer 48

A type of reproductive failure that appears after the generation of crosses between different species or subspecies.

Question 49

What is the Morphological Species Concept?

Answer 49

Defines a species by structural features.

Question 50

What does the Ecological Species Concept define species in terms of?

Answer 50

Ecological niche.

Question 51

What is allopatric speciation?

Answer 51

Gene flow is interrupted/reduced when a population is divided into geographically isolated subpopulations.

Question 52

What is sympatric speciation?

Answer 52

Speciation takes place in geographically overlapping populations.

Question 53

What can drive sympatric speciation?

Answer 53

The appearance of new ecological niches or sexual selection.

Question 54

Define polyploidy.

Answer 54

Presence of extra sets of chromosomes due to accidents during cell division.

Question 55

What is an autopolyploid?

Answer 55

An individual with 2+ chromosome sets, derived from one species.

Question 56

What is an allopolyploid?

Answer 56

A species with 2+ chromosomes, derived from a different species.

Question 57

In which organisms is polyploidy much more common?

Answer 57

Plants than animals ## Footnote Examples: oats, cotton, potatoes, tobacco, wheat.

Question 58

What is a hybrid zone?

Answer 58

A region in which members of different species mate and produce hybrids.

Question 59

What are the three possible outcomes when closely related species meet in a hybrid zone?

Answer 59

* Reinforcement * Fusion * Stability

Question 60

What occurs during reinforcement in a hybrid zone?

Answer 60

Strengthening of reproductive barriers ## Footnote Occurs when hybrids are less fit than the parent species.

Question 61

What happens during fusion in a hybrid zone?

Answer 61

Weakening of reproductive barriers ## Footnote Occurs if hybrids are as fit as parent species.

Question 62

What does stability refer to in a hybrid zone?

Answer 62

Continued formation of hybrid individuals ## Footnote Occurs when hybrids have increased fitness.