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Ecology 2483 > Lecture 4- Chapter 6: > Flashcards

Lecture 4- Chapter 6: Flashcards

1
Q

Georges Cuvier

A
  • came before Darwin
  • discovered extinction in 1813
  • extinction was a wild notion
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2
Q

Carl

A
  • father of taxonomy
  • made thousands of species
  • coined the term homosapiens
  • christian
  • believed he was doing God’s work
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3
Q

Charles Darwin

A
  • 1859: The Origin of Species
  • used the phrase “descent with modification”
  • natural selection (ex in book include hunting of bog horn sheep and cod fisheries)
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4
Q

What is Evolution (3 points)

A
  1. Descent with Modification
  2. Allele Frequency Change
  3. Populations evolve, individuals do not
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5
Q

Descent with Modification

A
  • Fossils: show descent with modification (In terms of teeth and limbs)
  • Species do change
  • Ex: stickleback fish, horses, and dinosaurs being extinct
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6
Q

Allele Frequency Change

A

-allele frequency changes within a population
-Populations of organisms we do see variation within them
-If there is strong selection on a population, we will see genotype changes
- Ex. Arizona desert white sand mostly certain mice want to be cryptic from their predators so they are less visible than other mice within the population

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7
Q

Ecology Definition

A
  • the interaction between organisms
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8
Q

Populations Evolve, Individuals Do Not

A
  • evolution never follows over evolutionary time
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9
Q

What are the Mechanisms of Evolution

A
  1. Mutation
  2. Natural Selection
  3. Genetic Drift
  4. Gene Flow
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10
Q

Mechanism of Evolution 1. Mutation

A

-Individuals in populations differ in their phenotypes
-Different alleles arise by mutation
-Ex. Elephants utilize their tusks for manipulating their ecology
-Recently, poaching has been very popular in places where they live
-To get their tusks, they just slaughter the elephants, take off their faces, and leave the body to rot
-Mutation produces tuskless elephants

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11
Q

Mutation Definition

A

-a change in DNA
-Can result from copying errors during cell division, mechanical damage, exposure to chemicals (mutagens) or high-energy radiation
-Very rare
-Provides the raw material on which evolution is based, while recombination and independent assortment rearrange the raw material into new combinations

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12
Q

Mechanism of Evolution 2. Natural Selection

A

-beaks of birds
-Finches have massive bills used for cracking seeds

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13
Q

3 Types of Natural Selection

A
  1. Directional Selection
  2. Stabalizing Selection
  3. Disruptive Selection
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14
Q

Directional Selection

A

-individuals at one phenotypic extreme are favoured
-Ex. large size
-Ex. the finches

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15
Q

Stabalizing Selection

A

-individuals with an intermediate phenotype are favoured
-occurs if there is 2 selective agents operating on both sides of the curve
-Ex. 2 predators and the gall

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16
Q

Disruptive Selection

A
  • individuals at both phenotypic extremes are favoured
17
Q

Natural selection is the Mechanism of Adaptive Evolution

A
  1. What is Adaptive Evolution
  2. Adaptations results from natural selection
  3. Adaptive Evolution can Occur Rapidly
  4. Adaptations are not perfect
18
Q

Mechanism of Natural Selection 4. Gene Flow

A

-alleles move between populations via movement of individuals or gametes
-this causes:
1. Populations to become more similar
2. New alleles can be introduced into a population
-Ex. gene flow introducing alleles for insecticide resistance

19
Q

Key Conceot 3: Natural Selection is the Mechanism of Adaptive Evolution

A
  1. What is adaptive Evolution
  2. Adaptations result from natural slection
  3. Adaptive evolution can occur rapidly
  4. Adaptations are not perfect
20
Q

Adaptations Results from Natural Selection

A

-Selects of traits that confer advantages
-alleles increase in frequency over time

21
Q

Adaptive Evolution can Occur Rapidly

A
  • Male bighorn sheep that are bigger with a bigger horn will win the battle
  • Have been losing land (habitat has been deteriorating)
  • They will continue to be hunted- even tho hunters must pay $100,000
22
Q

Adaptations are not Perfect

A

-Natural selection does not result in a perfect match between organisms and their environments
-Environments are constantly changing, and there are constraints on evolution

23
Q

Why Evolution isn’t Perfect

A
  1. lack of genetic variation
  2. evolutionary history
  3. ecological trade-offs
24
Q

Lack of genetic variation

A
  • Spraying with DDT killed populations of mosquitoes carrying malaria
  • Killed off any form of mutations
25
Q

Evolutionary History

A

-Whales perfect example of evolutionary history
-Evolutionary Constraint: Whales always need to return to the surface to breathe

26
Q

Ecological Trade- offs

A
  • Crab: Decreased mobility due to size
  • Snow Crabs - claws are small but legs are long trying to get away from predators
27
Q

Adaptive Ecolution is Driven by Ecological Interactions

A

-Organisms interacting with one another and with their environment
-For every fox that caught a bunny, one fox went hungry
-Evolution is constantly in motion, and the ecological context is under constant change

28
Q

Key Concept 4: Long-term patterns of evolution are shaped by large-scale patterns

A

a. Speciation
b. Adaptive radiation
c. Extinction
d. Mass extinction

29
Q

What Drives Speciation in a Single Population:

A

-Change in gene frequency
-There is gene flow between white mice and dark mice
-But overtime a river continues to grow between the two
-At this particular point, no gene flow would be able to occur
-This would cause the formation of 2 separate daughter species (since gene flow isn’t occurring)

30
Q

Species Concept Definition

A

-Those individuals in the population must be able to have offspring, and those offspring should be fertile

31
Q

Physical Barriers that Result in Reproductive Isolation and Speciation

A
  • Physical Barrier
  • Mutualism (behaviour)
  • Ecological Barrier
32
Q

George Cuvier

A
  • discovered extinction
  • Over evolutionary time we have rates of extinction and speciation
33
Q

Adaptive Radiation Definition

A
  • Repeated speciation events increases the number of speciation in a group
34
Q

Extinction Definition

A
  • species are also lost
35
Q

An Evolutionary Tree Definiton

A
  • a branching diagram that represents the evolutionary history of a group
36
Q

Extant Definition

A
  • is the opposite of extinct (means they are alive today)
37
Q

What does the Cambrian Explosion mean?

A
  • adaptive radiation in animals
38
Q

Key Concept 5: Ecological Interactions and Evolution Exert a Profound Influence on one Another

A

Evolution observed patterns of change
- Bacteria and archaea
- Multicellular life - red algae
- Animal life

Ecology 2483 (21 decks)

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