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Biology 103 > Module 1 Exam Review > Flashcards

Module 1 Exam Review Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Catastrophism

A

events in the past occurred suddenly and was caused by mechanisms that no longer operate

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2
Q

Uniformitarianism

A

mechanisms of change are constant over time

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3
Q

Lamark’s Hypothesis of evolution (2)

A
  1. Use and disuse- parts of the body used more become stronger
  2. Inheritance of acquired characteristics- organisms can pass modifications to offspring
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4
Q

Adaptations

A

inherited characteristics that enhance the survival and reproduction in specific environments

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5
Q

Natural Selection

A

a process in which individuals that have certain traits tend to survive and reproduce at greater rates because of these traits

  • Survival of the fittest
  • Not evolution but can lead to evolution
  • Generally adapts a population to its environment
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6
Q

Artificial selection

A

modifying species by selectively breeding individuals that posses a desired trait

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7
Q

Homologous structures

A

structures in different species that are similar because of common ancestry
Ex. forelimbs of whales and cats

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8
Q

Vestigial Structures

A

remnants of features that served a function in the organisms ancestry

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9
Q

Convergent evolution

A

independent evolution of similar features in different lineages

EX. CAM photosynthesis evolved independently at least 2x, gliders

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10
Q

Analogous features

A

features that share similar function but not common ancestry

- result of convergent evolution

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11
Q

Genetic Variation

A

differences among individuals in the composition of their genes or other DNA segments
- introduced into pop. via sexual reproduction & mutation

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12
Q

Mechanisms that contribute to variation (3)

A

crossing over, independent assortment of chromosomes, fertilization

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13
Q

Gene pool

A

consists of all copies of every type of allele at all loci in every individual in a population

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14
Q

Hardy-Weinberg Principle

A

states that frequencies of alleles and genotypes in a population will remain constant from generation to generation provided only mendelian segregation of alleles
(unless acted upon by agents other than sexual recombination)

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15
Q

Conditions of Hardy-Weinberg equilibrium(5)

A
  1. no mutations
  2. random mating
  3. natural selection
  4. extremely large population size
  5. no gene flow
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16
Q

Genetic drift

A

chance events cause unpredictable allele frequencies from one generation to the next

“population emerging from sampling error doesn’t reflect original population”

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17
Q

founder effect

A

few individuals become isolated from larger population and form a new gene pool that doesn’t reflect the larger one

NEW PLACE

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18
Q

bottleneck effect

A

size of population is reduced by natural disaster or human action, surviving population is not genetically representative of original population

SAME PLACE
- non-selective reduction

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19
Q

gene flow

A

Transfer of alleles from one individual to another

Gene flow= Gene movement + gene establishment

Greater influence in smaller populations

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20
Q

relative fitness

A

the contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals

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21
Q

Directional, Disruptive, and stabilizing selection

A

Directional selection: individuals at one end of the phenotypic range survive/reproduce more successfully than other individuals
Disruptive selection:individuals on both extremes of phenotypic range survive/reproduce more successfully than other individuals
Stabilizing selection:intermediate phenotypes survive/reproduce more successfully than do extreme phenotypes

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22
Q

Sexual Selection

A

individuals with certain inherited characteristics are more likely to obtain mates
- can result in sexual dimorphism

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23
Q

Biological species concept

A

defines a species as a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring

  • reproductive isolation
    Pro: based on evolutionary independence
    Con: not applied to asexual species & fossils
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24
Q

Reproductive isolation

A

existence of biological barriers that impede members of 2 species from interbredding and producing viable offspring

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25
Q

Prezygotic barriers

A

Blocks fertilization from occurring before the zygote is formed

  • habitat isolation
  • behavioral isolation
  • temporal isolation
  • mechanical isolation
  • gametic isolation

Lead to rapid speciation

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26
Q

Post zygotic barriers

A

barrier that prevents hybrid zygotes from developing into viable, fertile adults

  • reduced hybrid viability
  • reduced hybrid fertility
  • hybrid breakdown (infertile offspring)
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27
Q

other definitions of species

  • morphological
  • ecological
  • phylogenic
A
  • morphological: by structural features
  • ecological: by ecological niche
  • phylogenic: by groups on individuals that share a common ancestor
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28
Q

Allopatric Speciation

A

gene flow is interrupted when a population is divided into geographically isolated sub-populations
- occurs by geological remodelling or colonization (“different land”)

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29
Q

Sympatric speciation

A

evolution of a new species from a surviving ancestral species while both continue to inhabit the same geographic region (“Same land”)

  • can result from allopolyploid
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30
Q

Polyploidy, Autopolyploid, Allopolyploid

A

Polyploidy: when a species has an extra set of chromosomes(plants)
Autopolyploid: individual that has more than 2 chromosome sets that are all derived from a single species
Allopolyploid: when a sterile hybrid is changed into a fertile polyploid
Spontaneous increase in chromosome #
- Cannot interbreed with parent species so they are considered a new biological species

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31
Q

Radiometric dating

A

a method for determining the absolute the absolute age of rocks and fossils, based on the half-life of radioactive isotopes

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32
Q

Adaptive radiations

A

period of evolutionary change in which groups of organisms form many new species whose adaptations allow them to fill different ecological roles in their communities

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33
Q

phylogenic trees

A

depicting evolutionary relationships as a branching tree
there are no primitive species!!!*

  • homologous traits to reflect evolutionary relationships
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34
Q

clade

A

monophyletic grouping that includes an ancestral species and all of its descendants
- distinguished by shared derived characters

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35
Q

molecular clock

A

amount of genetic change is used to estimate the date of past evolutionary events

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36
Q

parsimony

A

choosing the simplest hypothesis, requires the fewest base changes

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37
Q

Evolution

A

accumulation over time of inherited changes in populations leading to species which are related

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38
Q

Darwinian fitness

A

Individual’s ability to survive reproduction

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39
Q

population

A

Group of organisms of a single species in the same geographical area
- smallest unit that can evolve (individuals adapt!)

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40
Q

Species

A

Group of organisms with common ancestry and physical structures that’re able to breed and have fertile offspring

41
Q

Essentialism

A

Organisms are created in specific forms

42
Q

Linnaeus

A

ancestral forms can reflect evolutionary relationships (descent with modification)

43
Q

Assumptions made on evolution

A

Evolution takes time!

  1. natural selection acts on phenotypes with a generation, so variation must be partly heritable for natural selection to result in evolutionary change between generations
  2. small evolutionary changes can occur rapidly, complex adaptations need multiple changes over many generations
44
Q

4 observations of natural selection

A
  1. variation in phenotype exists among individuals
  2. high reproductive potential= population increase geometrically
  3. individuals compete for limited resources
  4. “fit” offspring with characteristics matching current env. more likely to survive/reproduce
45
Q

Comparative anatomy

A

existence of homologous structures beneath phenotypically different characters- indicate shared origin

46
Q

Comparative embryology

A

Organisms that share common ancestor but were subjected to different selection pressure in adulthood were shaped differently in adult structures… but share common embryological stages

EVO-DEVO

47
Q

Molecular biology

A

Evolutionary origins are reflected in DNA

48
Q

Case study- Soapberry bugs

A

Bugs feeding apparatus changed when they transitioned from balloon vine fruit to flat-podded golden rain fruit, change persisted in lab
- change was adaptation (heritable) & not phenotypic plasticity

49
Q

Developmental biology

A

Species differ as adults but have similarities as embryos

- EVO DEVO

50
Q

How old is life on earth?

When did unicellular life evolve?

A
  1. 6 billion years old

3. 8 billion years old

51
Q

Evolution of LUCA (key points)

A

Inorganic mol. > organic mol. > self-replicating mol. > aggregations > progenote

  • early earth was highly volatile
52
Q

Evolution of eukaryotes

A

Endosymbiotic hypothesis:

  • Mitochondria arose from intracellular parasitic bacteria (env. conditions selected for endosymbiont)
  • primitive mitochondria had very efficient metabolism
  • mitochondria escaped toxic O2 atmo. & eukaryote got a “chef”)
53
Q

Evidence: endosymbiotic hypothesis

A
  1. Mitochondria/chloroplasts have own DNA, “like bacteria”
  2. DNA sequencing shows they were primitive bacteria moving inside primitive eukaryote
BUT they produce toxic ROS
Selective pressure> evolution
- Mitochondria moved to nucleus
- protective nuclear envelope
- ways to manage waste
54
Q

Great oxygenation event

A

photosynthesis by cyanobacteria increased O2 concentration in atmosphere

55
Q

Ediacaran fauna

A
  • Earliest complex multicellular organisms

- Large morphological diversity

56
Q

Cambrian explosion

A
  • Earth suddenly erupted into many new groups of organisms

- Organisms with modern body plans (segmentation)

57
Q

Extinction

- when can mass extinctions occur

A
  • 99.9% of species are now extinct

mass extinctions:
Extinction rate&raquo_space; speciation rate
Periodic (cyclical)
>90% of species go extinct

58
Q

Causes of mass extinction

A
  1. Gradual env. changes (press)
    - ocean anoxia, climate change
  2. Catastrophic event (pulse)
    - asteroid, volcano
59
Q

Extinction recovery

A

Extinctions create vacant niches

More complex the ecosystem, the more difficult/long the recovery

60
Q

How do we get rapid evolutionary change (evolutionary novelty)

A

Heterochrony= changes to timing of development

Hox genes= set of patterning genes

61
Q

Hox gene example: Ultrabithorax

A

Hox genes allowed formation of novel traits (new traits)

62
Q

Paedomorphism

A

When adult at sexually mature stage, maintains juvenile traits

Ex. salamander vs axolotl (external gills)

63
Q

Human paedomorphosis

A

Human as giant foetal ape (cranial morphology, etc.)

64
Q

How are traits selected for/against

A
  • selection of the fittest
  • evolution is not goal directed
  • Natural selection acts on phenotypes within a generation
  • small changes can occur rapidly but usually it is a slow process
65
Q

Other mechanisms of evolution

A
  • Sexual selection
  • Drift
  • Random mutations
  • Gene flow
66
Q

How is variation introduced

A

Measure variation:

heterogeneity & allelic richness

67
Q

Mutations

A

Heritable changes

  • In haploids, most mutations are harmful (bacteria)
  • In diploids, new mutations are hidden by other allele
68
Q

Case study: E. coli

A

Mutations can be good & lead to evolution/adaptation!
Rapid reproduction + high mutation = strength in numbers

  • E. coli were unable to aerobically citrate but with 1 mutation they were able to
69
Q

Sexual reproduction

A

Variation in genetic structure of organisms between generations, due to 3 factors:

  1. random mating
  2. random segregation of parental chromosomes in meiosis
  3. meiotic recombination between homologue chromatids/crossing over
70
Q

Sex is good when…

A

environment is unpredictable

Genes aren’t good

71
Q

Sex is bad when…

A

Genes are good already

Clone is better!

72
Q

Sex in large populations

A

all sources of random variation cancel each other out

As long as:
mating is random & population is big

73
Q

Balanced polymorphism

A

Active maintenance of variation

- diploidy, patchy environments, frequency-dependent selection

74
Q

Diploidy

A

Hides variation as recessive

75
Q

Patchy environment

A

Environment presents variation in a variable, variation in the population will be adaptive since organisms may occupy environment fully

dark and light moths > only dark in forest of dark/light trees

76
Q

Frequency-dependent selection

A

Specific phenotype becomes very frequent, environment can adapt to it (predator develops new hunting strategies)

Organism presents a phenotype deviating from it will become better adapted to the environment

77
Q

Case study: Sickle cell anemia

A

Trade off= heterozygote advantage

AA= can get malaria
Aa=  Resistant to malaria but may have disease
aa= fatal disease, resistant to malaria
78
Q

Case study: Beta-thalassemia

A

Heterozygote advantage

- Blood disorder that can protect from malaria

79
Q

Phenotypic plasticity

A

Pheno= genotype + environment

Ex. human height increasing
- diet, genes, environment

80
Q

Micro-evolution (short-time) forces

A

Changes in a short time frame

Non-random mating
- weed out weak alleles

Assortative mating

Inbreeding depression
- if you mate with relatives, increased chance of recessive disease

81
Q

Hardy-Weinberg equilibrium Equation

A

Allelic frequency: p + q = 1

Genotypic frequency:
p^2 + 2pq + q^2 = 1

p= frequency of allele 1
q= frequency of allele 2
p^2= frequency of homozygous dominant genotype
2pq= frequency of heterozygous recessive genotype
q^2= frequency of homozygous recessive genotype
82
Q

Case study: Greater Prairie Chickens

A

Bottleneck effect
human influence: habitat destruction

  • if you allow gene flow you can restore balance
83
Q

Case study: Afrikaner’s

A

Founder effect

Huntington’s disease is abnormally high

84
Q

Chris study example: selection

A

In mountains=
shorter reproduction time

Higher flowers, flower earlier

85
Q

Morphological (speciation)

A

anatomical differences
Pro: widely applicable
Con: subjective
(vulnerable to convergent evolution)

86
Q

Phylogenetic

A

Smallest phylogenetic group

Pro: widely applicable, testable
Con: few phylogenies available

87
Q

Reproductive Isolating Mechanisms (RIMs)

A
  • prevent gene flow between species
  • reproductive isolation between species can be pre/post-zygotic
  • Organisms that don’t sexually reproduce can be classified based on morphological & biochemical characteristics
88
Q

Behavioral isolation

A

Distinctive plumage, scents, calls

Required courtship behaviors

89
Q

Temporal isolation

A

-normally refers to lack of mating between animals with diurnal vs nocturnal habits

90
Q

Mechanical isolation

A

pollinator “coevolution”

91
Q

Gametic isolattion

A

Gametes cannot fertilize

  • incompatible sperm + egg
  • Molecular recognition on cell surfaces
92
Q

Sympatric speciation example

A

Apple maggot fly

hawthorn fruit= slow maturation
apples= introduced & mature faster > favored rapid larval development

Now 2 species, hawthorn and apple maggot

93
Q

Allopatric speciation example

A

Snapping shrimp

  • vicariance (habitat split)
  • shrimp isolated by isthmus of panama
  • population diverged bc no gene flow
94
Q

Case study: sympatric speciation in lake Malawi

A

Fish are territorial: lots of sexual conflict + rapid evolution

  • hybrids viable > mating behavior is RIM
  • sensitive to human activities bc water is now murkier
95
Q

Phylogenetics

A

Study of evolutionary relatedness among various groups of organisms

96
Q

Macroevolution: Gradualism

A

Product of microevolution & adaptive divergence along very long periods of time

Gradualism is rare, mostly punctuated equilibrium

97
Q

Monophyletic

A

Includes most relevant common ancestor

98
Q

Paraphyletic

A

Contains most recent common ancestor & most of descendants

99
Q

Polyphyletic

A

Lack common ancestor

Biology 103 (5 decks)

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