CourseCram Information Flashcards
(99 cards)
1
Q
what is evolution?
A
the accumulation over time of inherited changes in populations leading to species which are related
2
Q
what is Darwiian fitness?
A
an individual’s ability to survive and reproduce
3
Q
what is an adaptation?
A
an evolved feature that enhances an organism’s fitness
4
Q
what is a population?
A
a group of organisms of a single species living in the same geographical area
5
Q
what is a species?
A
a group of organisms with a common ancestry and physical structures that are able to breed and have fertile offspring
6
Q
what is a community?
A
a group of populations composed of organisms with common ancestry, sharing similae structures, functions, behaviours, and are able to interbreed in nature
7
Q
what is an ecosystem?
A
an interactive system composed of one or more communities and their abiotic environment
8
Q
what is a biosphere?
A
all of earth’s ecosystems considered together
9
Q
what does the darwinian revolution differ from? and how
A
- differs from essentialism
- essentialism believes that organisms are created in species form
10
Q
what is differential reproductive success?
A
if selected for, more likely to have babies that will survive
11
Q
does survival immediately mean reproductive success?
A
no
12
Q
what is the smallest unit that can evolve?
A
a population
13
Q
populations evolve while individuals _____?
A
adapt
14
Q
how was natural selection developed as a theory? what were the four observations
A
- variation in phenotype exists among individuals
- high reproductive potential means populations increase (for fittest) geometrically
- individuals compete for limited resources
- “fit” offspring with characteristics matching current environments are more likely to survivde and reproduce
15
Q
what is the evidence for evolution?
A
- fossil records
- comparative anatomy
- biogeography
- comparative embroyolgy
- molecular biology phylogenetics
- convergent evolution
- anthropocene infleunces
16
Q
what are fossil records? describe.
A
- allows one to observe the evolution from common ancestors to current living organisms
- date by radioactive isotopes (c14)
- limitation: many organisms don’t keave good fossils
- limitation: many environments are good at preserving fossilization
17
Q
what is comparative anatomy? describe.
A
- reveals the existence of homologous structures beneath phenotypicaly different charactersm which indicates shared origin
- limitation: similar function does not mean homology, and a threat to this thought is analgous structures (ex. bird wing vs bat wing)
18
Q
what is “evo-devo”?
A
comparative embryology
19
Q
what is comparative embryology?
A
- patterns of homology that aren’t really seen until early development
- organisms that share a common ancestor but were subjected to different selection pressures during alduthood were shaped different in their adult structures, but share common embyological stages
- ex. gill ridges in human embryos as evidence that humans evolved from aquatic ancestor
20
Q
what is molecular biology? describe
A
- it is the best way to look at evolutionary history
- the fact that all living organisms share the same building blocks (ex. DNA) it is a strong support for the idea that all living organisms share a common ancestor
21
Q
where is evolutionary history reflected?
A
in DNA
22
Q
what is phylogenetics? describe.
A
- species that are grouped according to homolgous features that have shared evolutionary origins
- “bifrocating tree”
- we do not evolve into, but have a shared ancestory
23
Q
what is convergent evolution?
A
- the addition of the same biological trait in different lineages
- complicates ancestory
- have the same answer to different evolutionary problems, which gives rise to analagous structures
- therefore you have to look at DNA to solve the problem of if they are different species
24
Q
what is anthropocene influences? describe.
A
- artifical selection: created a new species from a particular ancestory by selecting the best variats in the population for further breeding
- humans caused evolutionary change through selective breeding, antibiotic resistence, etc.
25
describe the case study of "Soapberry Bugs".
* flat podded golden rain fruit was introduced to the species
* natural selection existed in bugs with shorter beaks, that was favoured for this new introduction
* and variation presisted in the lab
* which meant that genetic change had occured, and was a product of evolution (meaning it was heritable)
26
what has to be present in order for life to evolve?
macromolecules
27
what was the chain for the evolution of planet?
inorganic molecules, organic molecules, self replicating organic molecules (RNA), aggregations (phospholipids), and progenote
28
where did archae arise from, and from that what arose?
from eubacteria arose archaea and eventually the first eukaroyte
29
what can natural selection act on?
heritable material
30
where did mitochondria evolve from?
intracellular parasitic bacteria, which describes why it is a very efficient metabolizer
31
where did the large diveristy of a protist arise from?
* from serial endosymbiosis
* brought about the ensymbiotic hypothesis: a class of hypotheses that view various organelles in eukaryotic cells as descendants of endosymbionts, (mitochondria, nucleus, chloroplasts)
32
what is the key evidence in the endosymbiotic hypothesis?
DNA sequencing shows a relationship between mitochondria, chloroplasts, and cyanobacteria
33
how are mitochondria passed down
via the egg
34
what are the two forms of macroevolution?
* gradualism
* punctuated equilibrium
35
what is gradualism?
the product of microevolution and adaptive divergence along very long periods of time, it is a constant pace of evolution, and it is very unlikely to be the entire full story
36
what is punctuated equilibrium?
* when evolution is not gradual
* very long and relatively stasis periods of time, interrupted by short intervals of intensive species turnover
* these episodes often include explosive adaptive radiations and cases of mass extinction
37
which is more likely to occur, gradualism or punctuated equilibrium?
puntuated equilbrium
* fossil records show evolution is not gradual, happens in bits
38
when do adaptive radiations occur? what does this cause
* rapid genetic change
* occur because of the apperance of a novel characteristic that opens a new adaptive zone (new set of environmental resources to be used)
* usually follow mass extinctions
* occupants will have to re adapt to the environment
39
what are mechanisms that promote punctuated equilibrium on a smaller scale?
* signifigant genetic changes in an organism from one generation to another
* ex. small pop + new environment = adaptive evolution which is bottleneck or founder effect
40
what are some advantages and disadvantages of multicellularity?
Advantages
* specialization into epithelial, connective, muscle, and nervous tissues
* allows an increase in size
Disadvantages
* requires communication
* requires attachment
* requires the ability to turn on and off genes
* requires genetic commitment (once you specialize, you never go back)
* an increase in size also causes a need for transport, storage, etc
41
what was the cambrian explosion? what did it result in?
* earth erupted into many new organisms
* this was the first appearance of anthropods
* the first appearance of organisms with modern day body plans
42
where did plants most likely arise from?
protists related to the modern day green algae
43
what are the key features of plants?
* vascularization: allows movements of nutrients and wastee
* seeds (gymno vs angio): allows the distribution of offspring
44
describe what plants colonization of land was like
* had to be able to maintain structure without the buoyancy of water
* only one aquatic protist lineage was able to successfully colonize land
* likely was a streptophyte algae
* then the anthropods followed
* then the land vertebrates followed (a new niche opened up)
45
what is the cause of mass extinction, and when does it occur?
* occurs when there is a cascade of biotic (ex. bacteria die off) and abiotic (ex. volcanic eruptions, acid oceans, etc) factors that decrease species diveristy
46
what is a benefit for mass extinction?
* opens up niches for adaptive radiation
* and causes a shift in the diveristy of life
47
what do extinctions clear out?
niches
48
what does extinctions cause an opportunity for?
rapid expansion and radiation
49
what is the role of adaptive radiation after extinction?
period of evolutionary change in which groups of organisms form many new species whose adaptation allow them to fill different ecological roles
50
what is the order of events after extinction?
extinction---- radiation---- speciation
51
what type of genes cause morphological diveristy?
regulatory
52
what is heterochrony?
genes that change the timing of development
* example: paedomorphosis (maintaining juvenile form)
53
what are the other mechanisms of evolution, besides natural selection?
* sexual selection: strong selective force, very similar to natural selection in the size of its force
* genetic drift: strong in small populations
* random mutations: ultimate source of variation
* gene flow: reduces drift between populations
54
what are the 3 types of genetic variation?
* mutations
* sexual reproduction
* balanced polymorphism
55
what are mutations and their relevance to genetic variation?
* changes in DNA sequences that leads to new alleles that, if naturally selected for, take over the gene pool
* an example of this is antibiotic resistance
56
what acts first, variation or selection?
goes variation then selection for that favourable trait
57
describe the case study of antiobitic reistance. What type of genetic variation is it?
* mutation
* bacteria has a high reproduction rate, high rate of genetic exchange, and a strong selection pressure
* antiobiotic resistance is acquired through: mutations and horizontal gene transfer
* resistance already exists, but selection pressure is added with antibiotics
* resistance is lost thorugh antibiotic use
* the fastest wat to encourage resistance is when you don't finish antiobiotics
HGT
* conjugation: passing DNA between cells
* transformation: free DNA
* transduction: phage
58
how is sexual reproduction a source of genetic variation?
* random mating
* random segregation of parental chromosomes in meiosis
* meiotic recombination through crossing over
59
how is sexual reproduction a source of genetic variation?
* random mating
* random segregation of parental chromosomes in meiosis
* meiotic recombination through crossing over
60
when is sexual selection vs asexual selection favoured over the other?
sexual
* if the environment is unpredictable
* if your genes aren't food
Asexual
* if your genes are good
61
what is polymorphism?
many alleles/phenotypes for one gene
62
what can lack of variation lead to?
extinction
63
what is balanced polymorphism?
the active maintenance of variation in a population
64
what are some of the sources of balanced polymorphism?
* diploidy: hides variation in the form of recessive, incomplete dominant, or co dominant alleles in heterzygotes
* patchy environments: adaptive maintenance of variation
* frequency dependent selection: usually happens a lot with sexual reproduction, when a specific phenotype becomes very frequent, the environment can adapt to it
* heterozygote advantage: maintains variation, especially needed in changing environments to survive (think sickle cell)
65
What is the hardy weinberg equilibrium?
* the genetic structure of a population remains constants generation after generation in the hardy weinberg equilibrium unless acted upon by agents other than sexual recomination
* measures the frequency of alleles in population
* p+q=1 and p^2 + 2pq +q^2 =1
* p= frequency of allele one
* q=frequency of allele two
* p^2= frequency of homozygous dominant genotype
* 2pq= frequency of heterozygous recessive genotype
* q^2= frequency of homozygous recessive genotype
66
how does hardy weinberg equilbria relate to evolution?
if the genetic structure of a population deviates from the equilbria, population is evolving
67
what are the forces of micro-evolution (small time scale)?
* non random mating( assortative mating and inbreeding) depression
* genetic drift
* gene flow
* natural selection
68
what is non random mating?
* selective
* when organisms do not have equal chances of mating based on their genotype
* assortative mating: (ex. short prefers short), can result in change in allele and genotype frequencies, reduces frequency of heterozygous
* inbreeding depression: refers to low fitness in inbred individuals due to increased homozygosity for rare defects, in a small population this increases
69
what is genetic drift?
* has something to do with sampling error (not getting the full picture with a small pop)
* two types of drift: bottleneck and founder effect
* bottleneck: same place
* founder: new place
* the two types of drift are common sampling error types that cause non selective drift, and don't originate from changes in fitness
70
describe the case study of the greater prairie chickens, the type of drift it is, etc.
* bottleneck
* pop. shrank from humans
* importation of stock from neighboring states led to habitat destruction
* conservation efforts tried to max. gene flow (bridge the population to reduce bottleneck) between potentially isolated species and increase genetic variation
71
describe the case study of the afrikanner's and the type of drift it is.
* founder effect
* hunnington's disease is abnormally high due to the founder effect
* 1/3 white south africans from about 40 founder
* 50% of 2.5 million poopulation have 20 names traceable to that ship
72
what is gene flow? explain
* gene flow mixes alleles among populations of the same species
* important to maintaing variation
* most gene flow is over short distances
* rare long distance gene flow may also be important to maintain genetic vatiation (conservation biology)
73
what is natural selection?
* it is not evolution, but can lead to it
* fitness= survival + reproductive success
* the process by which an organism is better adapted to the environment and has a higher chance of leaving more offspring
* out of all of the cases of microevolution, only natural selection generally adapts a population to its environment
74
what are the 3 ways in which natural selection usually works?
* stabilizing: central phenotype selected over the extremes
* directional: phenotypes in a specific direction are selected
* disruptive: extreme phenotypes are selectef for/the mean is selected against, typically in patchy habitats
75
what do "higher" flowers do?
flower earlier (elevation)
76
selection is determined by __?
the environment
77
describe the beak size/disruptive selection case study
* beak size
* small beaks eat small seeds
* big beaks eat big seeds
* therefore, selection against the mean means less competition
* intermediate beaks compete with both big and small
* results in disruptive selection
78
Can natural selection lead to perfection? explain why or why not
* no
* organisms are locked into historical constraints, and the possible variations on a trait are limited by pre existing forms
* evolution is about trade offs
79
what is the 3 step pathway of evolution?
* heritable variation
* selection
* evolution occurs if there is a change in allele frequency over time
80
what are the 3 different species concepts? what are each of their advantages, disadvantages, and criterion?
Morphological
* they look the same
* anatomical differences
* A: widely applicable
* D: vulrebule to convergent evolution
Biological
* most common species concept
* they can breed
* A: based on evolutionary independence
* D: not applicable to asexual species and fossils, must interbreed, and produce viable and fertile offspring
Phylogenetic
* shared ancestory
* A: widely applicable, and testable
* D: few phylogenies availble (what defines distinct species?)
81
What are RIMs (reproductive isolating mechanisms)?
* prevent gene flow between species
* part of biological species concept
* can be pre or post zygotic
* organisms that do not reproduce sexually can only be based on morphological and biochemical characteristics (based on this definiton)
* have the phases of speciation:
-be genetically seperated (doesn't always need to happen, sympatry), diverge (due to selective pressure), RIM (can no longer interbreed in nature)
82
what are pre zygotic isolating mechanisms?
* habitat isolation (ex. road across wetland)
* behavioural isiolation (ex. different mating called, courtship behaviours)
* temporal isolation (call more in the morning, in day, or in night)
* mechanical isolation (species won't cross pollinate)
* gametic isolation (the gametes cannot fertilize, incompatible)
* pre zygotic RIM leads to rapid speciation
83
what is post zygotic isolation mechanisms?
* reduced hybrid viability
* reduced hybrid fertility (ex mules)
* when the first generation might be viable, while the second generation would not be
* this is slow, and the baby has reduced viability
84
what is speciation?
* process of evoltuion of two or more distinct species from a single ancestor
* genetic exchange stops, new lineages go their independent evolutionary ways
* can occur via genetic isolation: when there is limited gene flow
* genetic divergence: a result of mutations, natural selection, and genetic drift
* can be divided into allopatric (diff land) and sympatric (same land)
85
what is allopatric speciation? describe.
* diff land
* consequence of geographical isolation
* small subpopulation migrates or becomes isolation, and then genetic drift
* seperated into dispersal and vicariance
* dispersal: individuals move to a new location
* vicariance: the habitat is physically split
* first step is physical, then you diverge
86
what is the snapping turtle vicariance case study?
* habitat was split
* shrimp were isolated by panama
* no gene flow and the populations diverged
* when together, the the two species fight and not mate (post zygotic RIM)
* and also an allopatric example
87
what is sympatric speciation?
* consequence of reproductive isiolation inside population range
* can result from hybridization (allopolyoidy)
* divergence can also occur when a mutation results in genetic incompatibility
ex. apple maggot fly (rhagoletis)
* hawthorn fruit has slow maturation
* applies: introduce species and mature faster (Ready to eat earlier)
* some switches to apple
* some maggot flies now prefered apples and rapid development
* became temporally (over time) diverged into 2 species (hawthorne maggot and apple maggot)
88
what are hybrid zones and ectonones?
* hybrid zones that can have divergence, with some crossing over
* hybrid zone called a cline
Clines can be:
* stable selection: for hybrid in cline (some crossing over to create a cline)
* reinforcement of speciation: poor viability of hybrid (seperated- not rly a cline there)
* homogenization: hybrid kinda blends in with the rest (larger)
89
describe the case study in Lake Malawi, and it's connection to sympatric selection and the cline
* water clarity declining brought them together
* murky waters means less picky sex (common that there would now be more hybrids)
* the cline kind of dissapeared, and it grew till it almost overtook
90
what is polyploidy?
* leads to rapid pre zygotic RIM
* a polyploid individual is produced from one species when a mutation results in the doubling of chromosome number
* can be autopolyploidy and allopolyploidy
91
What are autopolyploidy and allopolyploidy? explain.
Autopolyploidy
* individuals (plants) with more than 2 sets of chromosomes
Allopolyploidy
* the mating of 2 different diploid species resulting in an individual with polyploidy karotypes that might be able to self fertilize (an example of homogenization)
92
what is phylogenetics?
* the study of the evolutionary relatedness among various groups of organisms
* phylogeny is the evolutionary history of a group of organisms shown in a diagram
93
what are phylogenetic trees?
* graphically reperset hypothesis's about evolutionary history
* oldest abd most inclusive taxon at the bottom/trunk
* most recent taxa at the smaller branching spots
* nodes: where groups split
* branches: where evolution occurs
* tipds: endpoint taxons
* polytomy: a point where more than two branches diverge (unknown which one happened first)
* non static (prone to change)
94
what is the difference between monophyletic, paraphyletic, and polyphyletic?
* monophyletic: includes an ancestor and all of its desendencts (called clades or taxa)
* paraphyletic: include common ancestor but not all descendants (more common)
* polyphyletic tree: distantly related groups
95
what are homologous structures?
share a common ancestor, will contain more genetic similarities, and share a similar embryonic development
96
what are analagous structures?
* similar structures that DO NOT share a common ancestor (ex wings of insects vs birds)
* result from convergent evolution
* misleading when building trees
* can be resolved using homoplasies (fossil records or genetic similarity)
97
what is synapomorphy?
* trait we can use to build a monophyletic tree
* a shared, derived character (homologous) that provides evidence of the relationship between two taxa
* cladistic analysis is based on this
* characteristics of the common ancestor are called basal characters/symplesiomorphy
*
98
what is autapomorphy?
trait that is unique within a group
99
how can you determine which trait is derived or ancesteral?
* use an outgroup
* if trait is present in outgroup + all of ingroup= ancestral
* present in outgroup + some in ingroup= ancestral
* only present in some of ingroup= derived
