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AP Bio > Unit 7 - Natural Selection > Flashcards

Unit 7 - Natural Selection Flashcards

(70 cards)

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1
Q

Evolution

A

change in the genetic makeup of a POPULATION OVER TIME

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2
Q

Natural Selection

A

process which individuals that have certain traits tend to SURVIVE AND REPRODUCE at high rates than others due to traits

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3
Q

Phenotypic variation

A

can decrease/increase fitness

DNA sequence doesn’t matter

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4
Q

Selective Pressures

A

changes in the environment

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5
Q

Heritable traits

A

from PARENT TO OFFSPRING
- sexual reproduction (crossing over, independent assortment, random fertilization)
- random mutations
- adaptations to environment

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6
Q

Ways to increase fitness

A
  • more offspring = more survive
  • successful competition for resources = increase change of survival and reproduction
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7
Q

Fitness

A

reproductive success = evolutionary fitness

more changes in the environment will lead to more evolution/adaptation

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8
Q

Artificial selection

A

selective breeding by humans to encourage a desirable trait

can increase OR decrease genetic diversity

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9
Q

Population

A

a group of individuals that are the same species, live in the same area, and interbreed to produce FERTILE offspring

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10
Q

Gene pool

A

population’s genetic makeup

all copies of every type of allele

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11
Q

Fixed allele

A

1 allele present for a particular locus (where on a chromosome a specific gene is); an allele that is the only variant that exists for that gene in a population

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12
Q

Genetic drift

A

CHANCE event that cause a change in allelic frequency from one generation to the next

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13
Q

How does genetic drift affect a population?

A
  • most affects small population
  • increased mortality and decreased reproduction (from natural disaster)
  • loss of genetic variation
  • harmful alleles become fixed

does NOT produce adaptations (random event!!)

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14
Q

Bottleneck

A

large population is significantly reduced by a non-selective disaster

ex: fire, famine, etc

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15
Q

Founder

A

a few individuals isolate and establish a new population with a different gene pool; lose genetic diversity

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16
Q

Gene Flow

A

transfer of alleles in/out of a population; migration

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17
Q

Convergent evolution

A

similar traits but unrelated lineage due to similar selective pressures/niches

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18
Q

Analogous structure

A

pairs with CONVERGENT EVOLUTION

similar structure/function with different ancestors

penguins, sharks, dolphins: light color bellies but only because they adapt that way to the environment

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19
Q

Divergent

A

accumulation of differences in groups (due to DIFFERENT ENVIRONMENTAL PRESSURES) that leads to speciation (formation of NEW SPECIEIS)

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20
Q

Homologous Structures

A

pairs with DIVERGENT EVOLUTION

common ancestor/blueprint but evolves into different structures with different functions

humans, bats, cats: same bone structures in arms with fingers due to common ancestor but now has different functions

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21
Q

Coevolution

A

2 interdependent (dependent upon one another) species influence each other’s morphology

ex: prey/predator, plant/pollinator

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22
Q

Adaptive Radiation

A

ancestral species develop into different species and fills in different environmental niches

modifies homologous structures and is due to ecological opportunity

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23
Q

Gradualism

A

evolutionary chang is slow; small genetic change favored by natural selection

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24
Q

Punctuated

A

periods of stasis (no change) to rapid development (punctuated)

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25
What increases chance of survival?
increased variation will help populations survive in changing environmental conditions increased variation will mean more chances for an individual to have a favorable trait
26
Phenotypic advantage
fitness advantage in an individual
27
Selective pressures
biotic/abiotic factors that influence survivability - availability of resources - predators - disease - climate
28
Environmental factors
trait previously suited may no longer be suited after changed environment
29
5 principles of natural selection
1. variation 2. trait must be heritable 3. more offspring that can survive 4. traits that increase fitness are passed down more often 5. POPULATIONS CHANGE; not individuals
30
Hardy Weinberg
1. no mutations 2. random mating 3. no natural selection 4. extremely large population size 5. no gene flow
31
Geographical evidence
characteristics of habitat or land loss
32
Geological evidence
features of Earth overtime (fossils)
33
Physical evidence
phenotypes/traits of species
34
Biochemical evidence
chemical composition (molecules -- DNA, proteins)
35
Mathematical evidence
calculations, statistics, models, simulations
36
Fossils
visual of evolutionary change over time rate of carbon 14 decay: less carbon = older
37
Comparative Morphology
analysis of living and extincet structures
38
Embryotic Homology
similar embryotic development
39
Vestigial Structures
structures that are conserved even if they are no longer used
40
Molecular Homology
many species share similar DNA, animo acid sequences
41
Biogeography
related organisms are different in different places due to evolving in different conditions ex: finches in Galapagos, Pangea
42
Genome Changes
antibiotic resistant bacteria, pathogens = new diseases
43
Synapomorphy
derived characteristics shared by clade members
44
Derived
similarly inherited from most recent common ancestor
45
Ancestral
arose prior to the common ancestor
46
Monophyletic
includes most recent common ancestor and all descendants (grandparents and all grandkids)
47
Paraphyletic
most recent common ancestor but missing descendants (grandparents and some cousins are missing)
48
Polyphyletic
no common ancestor but has descendants (grandparents are missing but grandchildren are there)
49
Allopatric
physical barrier divides a population and is separated (geographic isolation) - prevents gene flow - usually caused by natural disaster
50
Sympatric
new species evolves while still in the same geographical region as ancestral species - reproductively isolated; when brought back together, and are able to interbreed = they are NOT distinct species
51
Prezygotic
prevents mating/hinders fertilization
52
Habitat - Prezygotic
live in different areas/habitats in the same area
53
Temperal - Prezygotic
mate at different times; time of day/year/season
54
Behavioral - Prezygotic
different mating rituals
55
Mechanical - Prezygotic
reproductive anatomy doesn't fit
56
Gametic - Prezygotic
proteins on eggs' surface don't allow for the egg and sperm to fuse
57
Postzygotic
prevent hybrid zygote from developing into a fully viable and fertile adult
58
Reduced viability
impair development/survival
59
Reduced fertility
hybrid can develop into an adult but is sterile
60
Hybrid breakdown
1st generation of hybrids survives and reproduces but 2nd generation is sterile
61
Microevolution
change in allele frequency ex: genetic drift, natural/sexual selection, gene flow
62
Macroevolution
large evolutionary patterns ex: adaptive radiation, mass extinction, stasis
63
Human causes of extinction
pollution, climate change, poaching, habitat loss/destruction, invasive species
64
Types of traits
Adaptive: increase chance of survival Deleterious: decrease chance of survival both depend on environment
65
Directional
selecting for 1 EXTREME trait
66
Stabilizing
select intermediate; AGAINST EXTREME traits
67
Disruptive
selecting for BOTH EXTREME traits
68
Sexual selection
chooses mate based on one/more traits; 1 sex has to compete for a mate - result in traits harmful to an individual; peacock big tail
68
Early Life
synthesize organic molecules from inorganic molecules with free energy (UV, electric discharge, heat)
69
RNA World Hypothesis
RNA was the earliest genetic material; created on primitive Earth and could self-replicate without other molecules Primordial soup: early oceans with inorganic and simple organic molecules; formed with free nucleotides

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