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Test 2 Flashcards

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1
Q

What are the two main approaches to defining a species

A

Taxonomic
-based primarily on distinct measurable differences
Biological
-based on inter-fertility among individuals

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2
Q

Biological species concept…when,who, what, theory

A

-Mayr 1942
Reproductively isolated

-focuses on the processes
-geographic isolation alone is not sufficient
-isolation does not have to be absolute
-must be possibly interbreeding in the wild
-does not apply well for bacteria, asexuals, highly self-fertilizing species or fossils

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3
Q

Where does speciation occur?

A

Often called geographic speciation
-due to involvement of geographical isolation
Allopathic speciation much more common & easier to evolve

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4
Q

What causes reproductive isolation …all the steps
(5)

A

-finding a compatible mate & mating, fertilization, development & growth of zygote, adult & reproduction, growth/survival/reproduction of offspring

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5
Q

Different kinds of barriers …7

A

-Pre-zygotic …prevent mating or fertilization
-geological, ecological
-temporal, behavioural (mate recognition)
-mechanical (genital structure compatibility)
-cellular (sperm-egg compatibility)

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6
Q

Pre-zygotic isolation in apple maggot flies

A

-host shift after arrival of domesticated apples in 1800s
-differences in timing of host plant fruiting (apple vs haw)
-different timing of fly mating on preferred host plant
-reduced fly gene flow by 94% in sympatry (same region)

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7
Q

Pre-zygotic isolation in abalone

A

-binding of sperm lysin preteen to egg viteline envelope receptor (VERL) required for fertilization
-molecular “lock and key”
-lysin/VERL interaction has coevolved
-different evolutionary changes in different species
-causes reproductive isolation due to fertilization incompatibility

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8
Q

Post zygote barriers …intrinsic and extrinsic

A

Prevent proper functioning of zygotes once they are formed
-caused by combinations of genes with low fitness in the hybrid
—-intrinsic: in viability, sterility, or abnormal development of hybrids
—-extrinsic: ecological mismatch of hybrid phenotype to environment

-not directly favoured by natural selection

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9
Q

Intrinsic post zygotic isolation hybrid examples

A

Mule is a sterile hybrid cross of
-male donkey 62 chromosomes
-female horse 64 chromosomes

Hinny
-male horse
-female donkey

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10
Q

Genetic distance and post-zygotic isolation in fruit flies

A

-The more that fly pairs are genetically differentiated, the more likely they are to be reproductively isolated
-review graph

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11
Q

Extrinsic post-zygotic isolation: example of poorly adapted hybrids

A

-mullerian mimicry in heliconius butterflies
-hybrids have aberrant colour patterns
-higher predation
-lower mating success

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12
Q

Is adaptive evolution required for speciation

A

-local adaptations by different populations can lead to reproductive isolation and speciation
-distinct evolutionary responses to different selective pressures
-LA no absolatuly mecessay, but accelerates population divergence and evolution of RI

-termed ecological speciation

-much current research aims to determine:
-the biotic and abiotic agents of selection
-the underlying ‘speciation genes’

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13
Q

Eda in fish

A

-a gene for understanding adaptation and speciation during colonization of freshwater lakes
-present in marine environments against large fish predation

-absent in freshwater
-increases growth rate
-greater winter survival
-earlier breeding

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14
Q

Review graphs

A

📈📉

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15
Q

Bop

A
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16
Q

Adaptive radiation

A

The evaluation of ecological and ohenotypic diversity within a rapidly multiplying lineage as a result of speciation
-originates from a single common ancestor
-the process results in an array of many species
-the species differ in traits allowing exploitation of a range of habitats and resources

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17
Q

Four features of adaptive radiation.

A
  1. Recent common ancestry from a single species
  2. Phenotype-environment correlation
  3. Trait utility
  4. Rapid speciation
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18
Q

What causes adaptive radiation

A
  1. Ecological opportunity
    -abundant resources
    -few competitors
    -often encountered on oceanic islands or their aquatic counterparts
    -
  2. Origin of a key innovation
    -toepad in anoles
  3. High rates of speciation characterize the class
    -test by comparing island to mainland class
    -
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19
Q

Hybridization

A

-the exchange of genes between species as a result of occasional inter-species mating
—-sometimes can reverse speciation process to merge two groups into one
-varies across tree of life
—-common in plants and fish, rare in mammals
-can result in complex patterns of variation
——can be evolutionarily significant for speciation, especially by polyploidy

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20
Q

Polyploidy

A

An organism, tissue, or cell with more than two complete sets of homologous chromosomes

-allopolyploidy
—-arises from duplicated karyotype following hybridization between species
—commonest type of polyploidy
(AAxAA—>AAAA)

-autopolyploidy
——-arises from duplicated karyotype within a species
(AA—>AAAA)

At

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21
Q

Alloploidy

A

An allopolyploid is an individual having two or more complete sets of chromosomes derived from different species.

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22
Q

Autopolyploidy

A

Autopolyploidy appears when an individual has more than two sets of chromosomes, both of which from the same parental species

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23
Q

Evolutionary significance to polyploidy

A

They are reproductively isolated from their diploid parents
—hence a form of sympatric speciation
They exhibit novel phenotypes
—allows exploitation of new habitats
Often show hybrid vigor due to heterozygosity, particularly in allopolyploids
Polyploid origin for approx 50% of flowering plants
—many crops plants & invasive species

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24
Q

Binomial nomenclature

A

Species naming
Carolus Linnaeus 1707-1778
-hierarchical system of classification

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25
What is the purpose of biological classification
Name is s key shared information on an organism Predictive power Enables interpretation of origins and evolutionary history
26
Taxon def and order
A single names taxonomic unity at any level -kingdoms -phyla -classes -orders -families -genera -species
27
Taxonomy
The theory and practice of classification and naming
28
Systematics
The study of biodiversity and the evolutionary relationships among organisms
29
A phylogenetic tree Point out 6 things
Terminal nodes :taxa Terminal branches: accumulated evolutionary change Internal branches: accumulated evolutionary change Internal nodes: common ancestor, speciation Outgroup taxon I group taxon
30
Why conduct phylogenetic analysis
Understand life history Undedtand large-scale patterns of evolution Understand how many times traits have evolved, how fast, under what condition
31
Monophyletic group
Complete set of species derived rom a common ancestor -a taxon whose members are derived from two or more ancestral forms not common to all ancestors
32
Paraphyletic group
Contains some, but not all species derived from a common ancestor -a single ancestor gave rise to all species in this group
33
Ancestral vs derived traits
A trait shared with a common on ancestor A trait that differs from the ancestral trait in a lineage
34
Homology v Homoplasy
Similarity of traits due to shared ancestry Similarity of traits as a result of convergent evolution
35
Cichlid fishes
Are an example of convergent evolution in feeding strategies
36
Why do we care about molecules
All life is related through branching descent Common genetic code is evidence that all life is related Evolutionary relationships among species are reflected in their DNA and protein —learning about protein function in one species can tell us about its function in others
37
Species relationships from DNA sequencing
Genes or parts of a gene can be sequenced for different species Species can be assessed for changes in the sequence of nucleotides Changes can be used to infer relationships in a branching diagram
38
Key innovations in phylogenies
-origin of novel trait resulting in adaptive radiation - arriers of the treat can exploit new resources or sets of habitats -usually associated with repaid evolutionary diversification
39
Why do some groups have more species than others - -sister h=group
-with one phylogenetic comparison it is difficult to say a key trait is involved -replicate comparisons of multiple groups adds more evidence
40
Her ivory associated with higher diversification rate is an example, fo what
Convolution between insects and plants likely drives rates of speciation in herbivores
41
Other impacts associated with greater diversification
-species with more sexual selection -animal pollination in plants -increased dispersal -increased range size
42
Lamarck says species will become what with time
More complex
43
Major transition in evolution
Greater complexity arises from greater cooperation among previously independent units -complexity = specialization -a small number of events led to major changes in how inheritance worked -previously independently evolving units merged, leading to higher-level complexity & specialization through division of labour
44
What is the unity of selection
-most phenotypic traits we study in organisms arose due to selection that increases the fitness of individuals —may or may not be good for the SPECIES —individual selection usually stronger than group selection -traits that are good for the species but that reduce firmness of the individual connot be favoured by the indivisible selection
45
When is cooperation adaptive
1. High relatedness -genes that lead to helping relatives can spread via natural selection 2. Reciprocal altruism -in cases where organisms repeatedly encounter each other 3. BUT cooperation sometime breaks frown ….cheated
46
What is the target of selection
Genes Selection on an individual is a kind of cooperation -different parents into one, segregation/recob/random mating ensures independently passed on
47
Two problems of cooperation
How do higher levels of organization stay cooperative ? To what extent can cooperation break down?
48
How do genomes stay cooperative
-many features of individual organisms prevent competition within an individual ——prevents evo within individuals ——align fitness interests -ensures that many genes succeed by enhancing the fitness of the organism
49
How does an individual genome stay cooperative
1. Mitosis and meiosis -alleles don’t compete -fair representation of gene variations 2. Development and multicellularity -staring from a single cell prevents initial competition among cell lineages 3. Unioarental inheritance of organelles -chloroplasts and mitochondria replicate asexually -prevents competition within cells of different organelle genomes
50
Explain fair meiosis
Keeps genome cooperative -50% 50% division of alleles
51
Cheating a fair meiosis
1. Meiotic drive -biased transmission -spread to higher frequency even while reducing the individuals fitness 2. Over-replication -Transposable Element (TE) -self replicating segments of DNA -TE replication separated from cellular replication -ensure their own over-representation of offspring
52
Meiotic drive in drosophila
Segregation distorted locus -ssxSs All offspring were Ss Expect 50% -S allel prevents proper s sperm formation -counteracting restorer alleles are favoured at other genes in the genome to silence the S allele
53
How do genomes not explode from transposition
Alleles arose elsewhere in genomes that silence TEs will be favoured by individual selection -mechanismisn controlling DNA & histone methylation -piRNAs and RNA interface may have evolved as silencing mechanisms Transposition-selection balance -transposition is a form of mutation that can disrupt a gene
54
Transposition-selection balance
-transposition increases TE abundance -natural selection against harmful efffects on the organism reduces abundance of chromosomes copies with most TEs —overall abundance results from a balance between these opposing forces
55
Mitochondrial transmission
-lack of mitosis and meiosis by plastids sets up potential for spread fo selfish eleements
56
How do mitochondria stay cooperative
Uniparental plastid I driven e stringly reduces competition within individuals -consistent with hypotheses that it evolved to maintain coooperation
57
New conflicts due to unipafental inheritance
Conflict of interest -maternal inheritance of cytoplasmic genome -biparental inheritance of nuclear genome Mitochondrial mutations that enhance maternal fitness can spread -even if cost is severe to male fitness
58
Cytoplasmic male sterility in plants
-new mutations in the mitochondria that make hermaphroditic plants male sterile can spread -favour mitochondria, transmission -can reduce fitness as a whole -leads do evo of Mum lead restorer alleles that re-enable fertility through pollen ——-arms race to co evolution of CMS & restorer genes
59
How do collections of cells stay cooperative
1. Starting from a single cell reduces competition within individual s 2. Separation of Germaine with limited numbers of cell divisions inhabits transmission of selfish cell lineages 3. Tumour suppressors. Other features inhibit unregulated cell division 4. BUT SOMATIC MUTATION IS INEVIT8SBEL IN LONG-LIVED MULTICELLULAR ORGANISMSS
60
Cancer as a selfish cell lineage
-spread commonly in tissue that is relatively undifferentiated —evolves resistance to treatment/immune system -illustrated the shirt-sightedness of the evolutionary process
61
Pests and evolution: the problem
We use chemicals to combat pests and pathogens We create strong selective pressure for resistance
62
Where does resistance come from
Q. Pre-existing genetic variation in the population 2. Gene flow 3.new mutations
63
Which weeds have more pre-existing resistance
Outcrossing It’s less in selfing weeds
64
Can we stop herbicide resistance
1. Multi-herbicide treatment -make new adaptation less likely -requires more comp,ex adaptation 2. Rotation of different kinds of herbicides -weeds regularly hit by different selection pressures BUT COULD SELECT FOR GENERALIZED RESISTANCE
65
Graph for evolutionary rescue
Nike swish
66
Malaria and mosquitos
700 k deaths a year Prevention = insecticides Strong selective pressure on mosquitoes has led to rapid evolution of resistance
67
Evolution-prof solutions
Tailor insecticide applicarion to knowledge of mosquito generation times & spatial distribution Goal: minimize selection for mosquito resistance while still reducing malaria transmission
68
Less aggressive drug treatment of malaria in mice resulted in…
-less evo of resistance -reduced infectiousness -similar health outcomes
69
Multidrug cocktails slow evolution of HIV resistance how
-Simple mutations unlikely to confer resistance to multiple drugs with different mechanisms of action -lower viral loads make multiple mutations less likely
70
True or false skin cancers evolve drug resistance
True
71
Evolutionarily informed cancer treatments
Strong, prolonged selection pressures using the same chemotherapy drugs may not be the best solution as it selects for resistance -cycling drugs, multi drug cocktails, lower doses of drugs - e better option? -ethical considerations make tests of theory for human application challenging
72
Biodiversity and extinction
-Extinction is a permanent elimination of a species -extinction is a normal evolutionary process ——-99% of all species that have ever lived are now extinct ———in unddisturbed ecosystems, extinction rates have been estimated at one species loss every 10 years -astoundingly increased rates of extinction during the past century ——-massive habitat destruction particularly in tropical regions ——at least 4000 to 6000 species per year
73
Five genetic issues and conservation biology
Loss of genetic diversity loss of heterozygosity inbreeding depression fixation of deleterious alleles in ability of populations to adapt
74
What are the factors to an of evo rescue
-Depends on population size, beneficial mutation rate, how much fitness was reduced
75
Ecology is what
-how organisms interact with each other and their environments -the distribution and abundance of species -the structure and function of ecosystems -the science of biodiversity
76
Who developed the endosymbiosis theory for the origin of mitochondria
-Lynn margulius
77
How many species are there
Globally -too many to count -many (>85%) still unknown to science -a eccentric estimate from rates of new taxa described cam to 8.7 million -just eukaryotes
78
Rank of biodiversity in the three level of life
Bacteria Eukaryota Archaea
79
Population Ecological community Ecosystem DEFINE
All individuals of the same species in one place at one time -a;l the species living together in one place at one time -all species plus non-living environment
80
Example of animal from,entire with large range and small range
Mountain lion …all of the America pretty much Pika …west of North America only
81
What determines where a species lives
Dispersal ——> abiotic conditions ——-> species interactions
82
What limits a species range
Dispersal Climatic or other inexhaustible conditions Food or other exhaustible resources Species interactions ——-these are all gradients, there are ideal and unideal areas of the gradient
83
Ranges of tolerances in environment gradients Draw the graph
Bell shaped symeptrical slope -ends are lethal zones
84
The sixth extinction
Ongoing mass extinction -human activities 232%of known vertebrates species are decreasing in pop size or range
85
What determines abundance
Malthus Influenced Darwin -population growth -human pop. S can’t grow faster than our resources -population decline when resources decline -Darwin inspired and writes the same for all species …competition -resources are abundant …competition gets stronger
86
Ecological niche
Combination of physical tolerances and resource requirements of a species -Hutchinsonian niche: an n-dimensional hyper volume
87
Global gradients
-temperature -rainfall -seasonality
88
Temperature is a function of
Latitude
89
Seasonality in high latitude is a function of…
Te,persture
90
Seasonality in low latitudes is a function of…
Rainfall
91
Rainfall depends on …
Atmospheric circulation, offshore currents, rain shadow
92
Hadley cells
Heated air rises from near the equator and cools at 5/10c/km Water vapours condenses and fall as rain near the equator Air warms as it falls Dry, high pressure air hits at 30+/- degrees latitude
93
Name the atmospheric cells and their directions
Hadley cells-north Ferrel cells-south Polar cells- north
94
Hadley cell s meet where
The inter-tropical convergence
95
Draw the intertropical convergence in July and January
96
Coriolis effect
The earths rotation deflects winds -objects appear to be deflected eastwards as they move away from the equator and deflected as they move towards the equator
97
Horse latitudes
No wind …doom horses to preserve fresh water -30 degrees
98
Landmass serves as …
Wind blocker
99
General trends of terrestrial vegetation
Vegetation growth increases with moisture and temp Becomes predictable as biomes Seasonality is secondarily important
100
Look over Whittaker’s diagram
101
Describe climate patchiness
Maritime is more climate moderated, continental kore extreme —-oceans provide thermal inertia Precipitation: Orographic precipitation-air forces up mountains undergoes cooling into rainfall Rain shadow -leeward mountain sides are dry
102
Niche limits versus geographic range limits… What are some of the exceptions
Transcendent biomes = ecological versatility, super generalist -Not at limits because of recent history, limited by other organisms
103
Ecological niche modelling
Otherwise known as species distribution modelling -uses data from species present distribution to predict where species can live -useful for modelling biological invasions how species range may shift due to climate change spread of vector borne diseases
104
Observed range shifts data from 2003 and 2011
2003 = species move polewards at a rate of 6.1 km per decade 2011 = species move polewards at a rate of 16.9 km per decade
105
What do physiologist study what do ecologist study what is physiological ecology
——study how organisms acquire energy and nutrients and tolerate physical conditions ——-ecologist study how organisms deal with their environment and how the environment limits where they live —— Eco physiology is simply the study of physiology in the contacts of an organisms ecology
106
What are the core ideas of physiological ecology
-Ranges of tolerance ultimately limit distribution -organisms are complex chemical reactions -reactions occur best at the optimum temperature and Osmetic conditions where fitness is maximized -many mechanisms for homeostasis have evolved to challenge hostile environments -maintenance of homeostasis requires energy and is often limited by constraints and trade-offs
107
Poikilotherms
Lack physiological means to deviate from environmental temperature fluctuate greatly reptiles —amphibians fish and invertebrates
108
Homeotherms
Must regulate heat balance to keep internal temperature within a narrow range —-Requires far greater energy then poikilotherms
109
Describe the modes of heat gain or heat loss
Radiation = heat transfer by electromagnetic radiation conduction = transfer by direct contact with substrate convection = heat transfer mediated by moving fluid evaporation = efficient cooling from wet surfaces redistribution = circulatory system redistribute heat among body parts
110
Explain Bergman‘s rule and Allen’s rule
Body size to surface area versus appendages/shape
111
Explain countercurrent circulation
Arteries and veins should be oppressed in appendages to conserve heat and separated in appendages to shed heat -Countercurrent flow maintains this gradient so heat is always flowing from outgoing blood to incoming blood
112
Explain weasels as a trade off to heat dynamics
Weasels are active all year and despite their warm weather adapted shape they live in the cold -Staying warm takes up to 50 to 100% greater metabolic demand -However their shape makes them much more effective predators to the pray they hunt underground

BIO120 (3 decks)

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