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Eco and Evo > Intro to Evolution > Flashcards

Intro to Evolution Flashcards

1
Q

Endemic

A

found in a particular area and nowhere else

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2
Q

Evolution

A

change in allele frequencies of a population across generations

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3
Q

Processes that cause evolution:

A
  1. Natural Selection
  2. Genetic Drift
  3. Migration (Gene Flow)
  4. Mutation
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4
Q

Microevolution

A

Evolution over a short time scale

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5
Q

Macroevolution

A

Evolution over a long time scale

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6
Q

Nicholas Steno

A

The first person to recognize that fossils were the remains of organisms (with Shark teeth).
Established Steno’s Law of Superposition- layers of rock are organized in a time sequence.
(1638-1686)

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7
Q

Baron Georges Culver

A

The first person to recognize extinction.
Said that fossils resemble but are not exactly the same as modern specie and that many past species are extinct.
(Land sloth observation)
(1769-1832)

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8
Q

Homology

A

The similarity among species due to inheritance from a common ancestor.
There are 3 levels.

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9
Q

Structural Homology

A

Similarity in adult form

e.g. vertebrate limbs of humans horses, birds, bats, and seals

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10
Q

Developmental Homology

A

Early in development, distantly related species often have homologous traits that are later lost.
e.g. early embryonic stages of a chick, human, and cat

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11
Q

Genetic Homology

A

shared gene patterns

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12
Q

Law of Succession

A

Extinct species were succeeded by similar species

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13
Q

Transitional Species

A

A trait in a fossil that is intermediate between ancestral (older) and derived (newer) species.

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14
Q

Jean Baptiste de Lamarck

A

Made the Inheritance of Acquired Traits Theory (INCORRECT): the continuous use of an organ results in its growth (and disuse causes it to shrink)
(1744-1829)

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15
Q

Thomas Malthus

A

He was a socio-economist.
He wrote the Essay on the principle of Population in 1978. It established the belief of the Malthusian Catastrophe.
(1766-1834)

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16
Q

Malthusian Catastrophe

A

Without regulation human population size will become too large, leading to famine/war/disease and a population crash back to subsistence levels.

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17
Q

Charles Darwin

A

Voyage of the Beagle
Collected over 10000 fossils and specimens
Worked tirelessly for 20 years, cataloging his findings, conducting experiments, working on details of his theory.
Published “On the Origin of Species” (1859)
Considered to independently formulate the Theory of Natural Selection along with Wallace
(1809-1882)

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18
Q

Alfred Russel Wallace

A 
Charted the Rio Negro in Brazil
Collected specimens
Ship catches fire
Travled to Malay Archipelago
Collects more than 125,000 specimens
Redefines biogeography of region
Recognizes the "Wallace Line"
Wrote theory to explain how species change and new species form
Sent it to Darwin
Considered to independently formulate the Theory of Natural Selection along with Darwin
(1823-1913)
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19
Q

The 4 Postulates of Natural Selection

A
  1. Individuals within a population have variation in traits
  2. Some of that variation is heritable
  3. Survival and reproductive success is variable
  4. Individuals best able to survive and reproduce is not a random sample
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20
Q

Heredity

A

the transmission of genetic characteristic from parents to offsprings

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21
Q

Heritability

A

the fraction of variation in a trait that

is due to genetic factors

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22
Q

Gregor Mendel

A

Discovered:

  • alleles
  • each Gamete carries only one factor
  • independent segregation

-dominate and recessive factors
(1822-1884)

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23
Q

Fitness

A

the ability to survive and reproduce offspring relative to other individuals within the population

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24
Q

Selection pressure

A

something that reduces the fitness of individuals (abiotic or biotic)

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25
Adaptation
- a heritable trait that increases the relative fitness of an individual in a particular environment - causes natural selection
26
Polygenic trait
controlled by multiple genes
27
Artificial Selection
-deliberate manipulation of fitness by humans through selective breeding - wildtype corn -> growing the plants that produce max corn -> the corn we have today - dog breeding
28
Directional Selection
- changes the average value of a trait - phenotype higher or lower than mean has highest fitness - the mean move towards the direction with high fitness - genetic variation is reduced
29
Stabilizing Selection
- reduces variation in a trait - phenotype higher and lower than mean has low fitness - mean stays the same
30
Disruptive Selection
- increases variation in a trait - phenotype higher and lower than mean has high fitness - mean could stay the same
31
Balancing Selection
- genetic variation is maintained - balance among multiple alleles in terms of fitness and frequency - no single allele has distinct advantage - environment varies over time
32
Heterozygote Advantage
the trait that is heterozygous has the the highest fitness
33
Frequency-dependent Selection
- common trait and rare trait that oscillate | - the scale eating cichlid fish
34
Sexual Selection
- natural selection on traits that influence the ability to obtain mates or chose good mates - usually acts on males more than females i. e bird of paradise mating dance video
35
Honest Signals
- traits that convey reliable information | - male-male competition, handicap (peacock feathers)
36
Fitness trade-offs
e.g. deep bills good for eating but bad for other things
37
Pleiotropy
- single gene affects multiple traits | - results in genetic correlation
38
Genetic Drift
- change in allele frequencies in a population generations due to random events - produced by sexual reproduction - affects the whole genome - usually will result in a reduction in average fitness
39
Sampling Error
- what leads to genetic drift - the magnitude of the drift is inversely related to the population size - reduces genetic diversity - coin flipping example
40
Founder Effect
- a chance change in allele frequencies when a new population is established - e.g. colonization of an island
41
Populations (genetic) Bottleneck
- a sudden, random reduction in population size (alleles) | - e.g. by an environmental event
42
Migration (Gene Flow)
- movement of alleles between populations - makes populations more similar genetically - random with respect to fitness - can increase or decrease genetic variation/diversity
43
Mutations
- changes to DNA - ultimate source of new alleles - increases genetic diversity - generally random - effects on phenotype: none, changes in protein or protein expression, absence of protein - point mutation, chromosome-level mutation, lateral gene transfer
44
Deleterious
- mutations that mostly lower fitness - e.g. since most organisms are well adapted to their environment, mutations in coding/regulatory regions mostly lower fitness
45
Common Views of Evolution of the 19th century and Earlier
- species are fixed (unchanged) - species are independent and do not have common ancestry - earth is young - comes from ancient Greeks such as Plato and Aristotle
46
Fossils
the preserved remains or traces of organisms from prehistoric times
47
misconception: evolutionary change occurs within organisms
correct: natural selection sorts existing variants, evolutionary change occurs in populations
48
misconception: adaptations occur because organisms need them
correct: mutations occur by chance, evolution is not directed toward a goal
49
misconception: organisms sacrifice themselves for the good of the species
correct: alleles that decrease fitness - decrease in frequency due to natural selection
50
misconception: evolution perfects organisms
correct: trait evolution has constraints and trade-offs - could be lack of genetic variation - fitness trade-offs - perfection cannot truly be attained because it is a moving target
51
Natural experiment
- instead of comparing groups created by direct manipulation under controlled conditions, natural experiments allow researchers to compare treatment groups created by an unplanned change in conditions - e.g. finch experiment with drought
52
Genetic correlation
- occurs when a single gene affects two traits - caused by pleiotropy - e.g. beak width and depth gene Bmp4
53
Gene pool
-a single group in which all of the alleles from all the gametes produced in each generation go
54
Hardy-Weinberg Principle
a mathematical null hypothesis for the study of evolutionary processes
55
What important assumptions does the Hardy-Weinberg Principle makes?
``` Random mating No natural selection No genetic drift (random allele frequency change) No gene flow No mutation ```
56
Purifying selection
-when disadvantageous alleles decline in frequency
57
Sexual dimorphism
refers to any trait that differs between males and females
58
Ecological (or environmental) Selection
favor traits that enable organisms to do things other than obtain mates such as survive in their physical and biological environments
59
The Founder Effect
a change in allele frequencies that occurs when a new population is established
60
Point mutation
- a change in a single base pair in DNA - new allele - a change in gene regulation
61
Chromosome-level mutation
- a change in the number or composition of chromosomes - gene duplication - loss of gene function or new alleles
62
Lateral gene transfer
the transfer of genes from one species to another
63
A neutral allele
an allele with no effect on fitness
64
Gene that expresses beak width and depth in finches
Bmp4
65
Gene that expresses beak length in finches
Calmodulin
66
Loss
frequency of 0 caused by genetic drift
67
Fixation
frequency of 1 caused by genetic drift
68
Who did the experiments of the finches in the Galapagos?
The Grants
69
Bateman-Trivers Theory
- predicts that females should be choosy, males compete with each other - Females generally invest more resources in offspring - Female fitness limited by these resources - male fitness limited by access to mates
70
What are females choosing?
- Good resources - Access to food or nesting sites - Nuptial gifts - Chemical defenses - Good genes - Honest signals
71
What are the only mutations that are heritable?
Germ line mutations
72
Intersexual Selection
the selection of an individual of one sex for mating by an individual of the other sex
73
Intrasexual Selection
the selection of an individuals of the same sex competing for a mate
74
Biological Effects of Climate Change
- geographic range shifts - phenology shifts - evolutionary adaption - extinctions - ocean acidification

Eco and Evo (15 decks)

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