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99 Cards in this Set

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Sexual Dimorphism

describes the significant difference between males and females of species (e.g. body size/ coloration).

Asymmetry of sex

-females invest in eggs; males invest in sperm. Female investment in offspring (eggs/ prenancy) is greater than male investment (sperm).

-Eggs are expensive while sperm are cheap

T/F: A few males become fathers, but all females have offspring.


-males mate w/ as many females aspossible to increase reproductive success

-females are choosierto insure reproductive success

Females are a ______________. Therefore, males compete for females, and females choose males to mate with.

limiting resource

What are 3 forms of male-male competition?

-combat: fight/ challenge males for access to females or other resources

-sperm competition: be last to mate to remove old sperm

-infanticide: males kill offspring of other males


Maleswith more elaborate trait (body size, horns/antlers) can out-compete othermales

T/F: There is a large variance in reproductive success. Many males have high reproductive success while few males have low RS.


- many males have low RS

- few males have high RS

-relatively few males do mating

________ is a nonrandom mating pattern in which individuals with similar genotypes and/or phenotypes mate with one another more frequently (i.e. larger males mate w/ larger females).

Assortative mating

Sperm Competition: Blue Gill Fish

-sneakers: "hit and run" strategy; higher sperm density

-female prefer to mate w/ parental males

-parental males: higher sperm longevity

_______ are the choosier sex. Whyshould females prefer males with exaggerated traits that seem arbitrary and mayeven be dangerous to the male’s survival?

females; confers to a benefit

What are 4 models to explain female mate choice?

-Direct Benefits

-Good Genes

-Runaway Selection

-Sensory Bias

Direct Benefits Modeland Mate Choice

females choose mates that provide them with some resources which increase their fecundity and/or survival; some females may prefer males to provide them w/ resources that increases their reproductive output (i.e. nuptial gifts- given by males to females to enhance her life)

Good Genes Model and Mate Choice

-males must produce "costly" indicators in order to signal females of the male's "Fitness". It requires energy to produce/ maintain exaggerated features.

-The females must identify good/strong genotypes to produce offspring w/ good genes

-honest indicator traits are costly to produce (therefore, it would be costly to fake)

Sensory Bias Model and Mate Choice

-Females prefers certain male traits, but not because of any mating benefits

-Females respond to stimulus (signal) associated with some benefit other than mate choice

ex) males gives vocalization and females are attracted to it

What are the advantages/ disadvantages to living in groups?

Advantages: close proximity to potential mates, sharing/ division of duties, and protection in #'s

Disadvantages: social hierarchies (individual interests subordinate), exploitation of individuals, and the chances of competition for resources increase (no sharing)

Interaction of living groups can have what 4 outcomes?

-cooperative: actor & recipient benefits

-selfish: actor benefits while recipient harmed

-spiteful: actor & recipient harmed

-altruistic: actor harmed while recipient benefits

__________ - trait inhances or increases the relative likelihood of reproductionor survival of others

___________- selection process that favorstraits benefitting offspring and relatives"

Altruistic Behavior; Kin Selection

___________ leads to kin selection, which is based on spread alleles that increase ________ fitness

Altruistic Behavior; indirect fitness

____________- nonreproducingind.’s (who are sterile) who take care of offspring (workers);rear offspring.

Eusocial Animals

The explanation for eusocial animals is ________, which benefits the individual through _________ (individual's own reproduction; benefits you) and __________ (reproduction of relatives; benefits others)

kin selection; direct fitness; indirect fitness

Direct Fitness

-number of personal offspring

-more offspring= more copies of genes/ genotypes

-benefits YOU

Indirect Fitness

-benefits by helping relative survive/ reproduce

-relative share a proportion of your genes (coefficient of relatedness)

-benefits OTHERS

Coefficient of relatedness

r ; refers to individuals sharing genes w/ their relatives.


Maleshaploid, develop from unfertilized eggs and females diploid develop fromfertilized eggs. Males have no fathers

-female bees (ants and wasps) are more closely related to their sisters than to their own offspring.- and to other females/ sister pairs in diploid state

What is life? (5)


-structural organization


-growth and reproduction

-response to environmental stimuli

All life is subject to and to have evolved by _________.

natural selection

Macroevolution refers to evolution _______ the species level. Drivers includes _____________ and ________, calculated as changes in numbers over time.

above; speciation (or origination); extinction

_________ refers to the number of species at a time interval (number of species present at one time). What's the equation?

Standing Diversity

SD= initial species diversity + originations - extincitons

___________ refers to species diversifying into a large number of highly specialized descendant species. It occurs to when organism reach a new environment and is able to exploit several "life-style", causing the organism to split into different species (i.e. Darwin’s Finches; dif. Foodsource, so develop dif. Beaks to exploit the source).

Adaptive Radiation

What are 2 causes of Adaptive Radiation?

-ecological opportunity (vacant habitats w/ few competitors)

-Adaptive Breakthrough (morphological innovation allows exploitation of new resource)

(i.e. Darwin’s Finches; dif. Food source, so develop dif. Beaks to exploit the source).

Adaptive Radiation can occur at different locations w/ similar environments/ ecological opportunities. What type of evolution may this bring among separate species?

convergent evolution- when2 species that don’t share a common ancestor evolve similarly because of the same environmental/ecological characteristics and opportunities. They have dif. Ancestral origin but dev. Similar features to suite theirniche (i.e. sharks/ dolphins)

note- Divergentevolution is when 2 dif. Species w/ same ancestral origins (common ancestor)evolved differently (i.e. carpals of human/ horse).

Adaptive radiation is a combination of __________ and __________.

morphological innovation & ecological opportunity

Stasis refers to a long period of ___________ in a lineage. Evidence includes known phylogeny-ancestral-descendant lineages & dense/ continuous fossil record.

very little/ no change;

species may appear/ persist for mya w/o change

Phyletic Gradualism

illustrates evolution as gradual, slow and steady. Natural selection operates over long periods of time. There's a steady transformation of whole species into new ones. Speciation/ branching events occurs via Anagenesis.

Punctuated Equilibrium

illustrates evolution as quick bursts and rapid change. Speciation occurs in random, quick bursts. Speciation/ branching events are called cladogensis

Anagenesis vs Cladogensis

Anagenesis- refers to an extended amount of time w/o branching points (speciation)

Cladogensis- refers to branching speciation events (speciation)

(see fig. 15.32)

T/F: Stasis occurs from a lack of genetic variation.

False; It's not due to lack of GV. Simpler doesn't mean slower!

2 types of evolutionary trends are passive & active. What's the difference between the 2?

Note- trends: value of character changing over time

Passive- character shift in either direction. No direcitonal tendency to change, but the precursor starts at a minimum size.

Active- directional character shift.

Species Selection


differential success must be the result of selection upon species-intrinsic properties (rather than properties of genes, individuals, or populations w/in species).

Dispersal vs Vicariance

-Dispersal: movement of populations from one region to another. Species disperses across an EXISTING barrier

-Vicariance: formation of geographic boundaries resulting in separation of populations. species EXISTED- then were separated and underwent allopatric speciation.

NOTE- Area Phylogeny: replaces species names with areas where taxa originated/ lived

(see L11- slide 32)

Vicariance is an example of what type of speciation?

Allopatric Speciation- occurs when populations of the same species become vicariant, or isolated from each other to an extent that prevents or interferes with genetic interchange

Viral Reassortment

evolution; a type of horizontal gene transfer. Genetic material from different strains get mixed into new combinations within a single individual- strains rapdily change, which requires new drugs to fight off disease

SARS Virus- host shift

-virus that original infected Chinese bats, but moved to humans

-viruses have ability to switch hosts

How does evolution affect our health?

There a lot of things about humans/ their systems are built that they sharecommon ancestry w/ Tiktaalik.

left off on slide 7


-the evolutionary transition from fish to amphibians.

- There a lot of things about humans/ their systems are built that they sharecommon ancestry w/ Tiktaalik that may pose problems for humans now

-EX) choking is a consequence that food/ airpassageway crosses each other. Thisisn’t a problem w/ fish, but became problematic through evolution

Why humans are more likely to choke (3)

-Foodand air cross paths

-Uprightposture means gravity doesn't help guide food

-Droppedlarynx- big gap between soft palate and epiglottis

Our evolutionary constructs that may serve us advantages (i.e. dropped larynx for speech) may serve as disadvantages (i.e. more proned to choking)

Thrifty Genotype

problems for us now are a consequence for living a sedimentary lifestyle (i.e. not moving our bodies), whereas it didn't pose a problem for our ancestors because they were constantly active/ foraging. Anatomical arrangement of organisms makes sense, but because we live SL, some of our anatomy may cause problems (could've been beneficial at some point)

ex) Fat- energy storage then, but now poses problems

ex) Vericose Veins- pool of blood in our legs due to inactivity. Wasn't problem for ancestor

Phylogenetic inertia

-reason why evolution doesn't fix anatomy flaws

-refers to that species can not evolve backwards or from scratch- evolutionary history of species maintains stable mechanisms.

ex) horse have fused digits/ hoof- what if it wants opposable thumbs? It is difficult to evolve opposable thumbs because PI acts as a force to keep the hoof as it is

ex) although position of male gonads may make humans more pronned to hernias, you can't unevolve that trait

T/F: Evolution strives for perfection.

False; evolution doesn't strive for perfection. There are things that allow animals to best fit in their current environment, but it may disadvantageous in other environments (there are tradeoff's)

How humans affect evolution: horned-rams & fish

Hunters changed breeding pool due to what they hunt- a form of artificial selection

rams- only hunt large-horned, so small-horned will survive/ reproduce for small-horned offspring

fish- large get caught in nets while small fits through/ escapes. Small will reproduce small offspring

How humans affect evolution: agricultural pests/ disease vectors. What's the pattern (5)?

This is a form of coevolution; apply pesticide and insects able to develop resistance.

-invent new method of killing

-selective pressure

-evolve resistance



Why does giving subtheraputic doses ofantibiotics to food animals contribute to theevolution of antibiotic resistance?

Ongoing selection + preserving geneticvariation = efficient evolution of resistance

Antibiotic resistance is an example of what type of selection?

Directional Selection; population keeps evolving in 1 directionto outpace the drug that is being applied. Selection will always occur to preservevariation.

Genetic Drift and the health of species

GD- Stochastic (random) changes inallele frequencies. Foreach variable locus (gene), one allele will eventually fix. Smallpopulations experience faster drift, because sampling effects are stronger.

-As a result, smallpopulation have less genetic variation, and gives them less ability to survive.

How does Genetic drift affect the average fitness of thepopulation?

-It fixes potentially deleterious alleles(i.e., frequency —> 100%).

-Itreduces geneticvariation. Why is that bad? Less adaptability, more inbreeding(deleterious recessives).

-With little variation, population may not have alleles that work well in a new environment and adapt to new selective pressures (i.e. new diseases)

Evolution and Climate Change- flowers & Torrey Pine (tree)

-Flowering time of plants changed due totemperature changes- changes ecosystem.

-Warmingeffects this because it affects everything that uses the plant (i.e.pollinators)- changes ecosystem

-Rangeshifts and barriers to movement. TP is moving northward & is expanding geographic range Indirectly related to climate.

Phenotypedepends on the effects of both ______ and ____________

genotype and environment

ex- Atdifferent elevations, specific genotypes grows better

_________ refers to uniform structures (look very similar) that are repeated. They develop into the same form. (EX- legs in some insects, leaves of a tree, teeth in mammals)


__________ is an evolutionary change in the timing or rate of developmental events, which can affect many characters at once.

What's difference between allometric growth/ heterochronic growth?

-Allometric Growth: refers to dif. growth rates of a particular organism (i.e. a baby has a bigger head than limbs compared to adult)

-Heterochrony/ heterochronic growth: refers to timing of developmental events/ used for comparison of dif. organisms (i.e. dev. of fins of 1 fish species is heterochronic to that of another, resulting in dif. shapes/ sizes)

Because different parts of the body grow atdifferent rates (_________), dramatic changes may result fromchanges in the timing of developmental events.


T/F: The head grows at a slower rate than the rest of the body from birth to adulthood, which is an example of heterochrony.

False; it's allometry

HOX Genes

regulatory genes, which controls the transcription of other genes. They don't encode structures, but they provide positional information- they tell a cell where it's at in the body. They are responsible for the location of certain structures (i.e. mutant HOX can lead to flies growing legs where antennas should be)

What are the most diverse group of eukaryotes?


T/F: Relatively few genes regulate diversity.



involved in controlling all major aspects of development, including male and female gametophyte development, embryo and seed development. It helps explain developmental pathways of different sections of flowering plants

T/F: Increasing the number of Hox genes may have permitted greatermorphological complexity in vertebrates.


Developmental Constraint

ex) why don't pigs grow wings/ fly?

refersto that organisms don’t evolve certain traits that may be advantageous becauseit would require too much alteration to their developmental process. Altering their DP may be fatal, and it may require so manyother drastic changes in their development that they are unlikely to arisethrough mutation- their development constraints them from change!

T/F: Spandrels are designed to display mosaics.

False; original function is to hold up the arches. Mosaics exists as secondary function of beauty.

i.e. feathers first function is for warmth; secondary function is for flight

The transition from teeth to baleen in whales is an example of what type of evolutionary change?

Macroevolutionary Change


-inherited traits that makes an organism more fit in its environment

-product of natural selection

-phenotypic trait molded so individuals have higher probability of surviving and reproducing (fitness)

In order to determine if a trait is adaptive, there must be a link between _______ and ________.

trait and fitness

What is life? (5)

• homeostasis• structural organization• metabolism• growth and reproduction• response to environmental stimuli

From RNA to DNA (3)

• DNA more stable

• has repair mechanisms not available toRNA

• allowed for specialization of cellsi.e. DNA genetic storage system and RNA involved in cell messenger system

All life forms shares a ________.

common ancestry

What was the common ancestor of alllife forms like? (4)

–probably much like modern bacteria

–contained DNA

–fairly complete metabolism

–more like Bacteria, less like Eucarya/Archaea

When did the 1st ancestor appear? Describe Ladder of Life

4.5-3.5 billion years ago; LOL: Notsingle species but community ofspecies that traded genes- refers to shared characteristics

lifeis a web; a lot of transfer of genes between early life

Where Did Viruses Come From?- Escaped Gene Hypothesis

virusescould have been bits of DNA/ RNA that “escaped” from genes of larger organisms

Where Did Viruses Come From?- Reduction Hypothesis

virusesmay have once been small cells that parasitedlarger cells

Where Did Viruses Come From?- Relicts of the RNA world hypothesis

virusescould have evolved from complex molecules of protein and nucleic acid at thesame time as cells 1stappeared on earth

How old is Earth?

4.6 billions years old

Evolution of eucaryotic cells was a major transition, which involved _________________, where organells (i.e. chloroplast/ mitochondria) obtained by being acquired by symbiotic bacteria.


Endosymbiosis is an example of what type of relationship.

Mutualism- a symbiotic relationship where chloro/mito benefits from protection while host cell benefits from energy source

How long ago did multicellular life appear?

565 million years ago

Major transition of solitary-group living involved what benefits/ disadvantage?

benefits:foraging in groups, increased protection from predators

costs: transmission of parasites

Describe the Cambrian Explosion

-~542 mya

-high rate of speciation

-explosive radiation of forms representing dif. body plans

Despite Cambrian Explosion, _____ genes were conserved (relatively few are responsible for variation), which controls the body plan of an embryo & determines the type of segment structures that will occur.

Hox Genes

How long ago did modern homo sapiens 1st appear?

100,000 ya

What are 3 macroevolutionary patterns?


-adaptive radiation


End-Permian extinction

-245 mya

-greatest mass extinction

-dominant amphibians were replaced byancestors of mammals and dinosaurs

-multiple causes:–sea-level changes–climate change-increased temp.–change in ocean and atmosphere chemistry-low oxygen and increasedacidity–volcanic eruptions

End Cretaceous extinction

-65 mya

-dinosaurs wiped out

-created ecological opportunities

-Cause: asteroid

Effects of the impact:–affected climate, ocean and atmospherechemistry–SO2 and water vapor thrown in the aircreating acid rain–particles blocked solar radiation - earthcold and dark –massive earthquakes trigger volcanicactivity–enormous tidal wave - 4 km high


- thejoint evolution of two or more species based on interactions between them

-No genes exchanged

Congruent vs Incongruent relationship

Congruent- parallel association; 2 species evolve at same time

-incongruent- host switching/ horizontal transfer; evolve at dif. rate



-Multiple species interations- mimicry

-anatagonistic: one benefits while the other doesn't; predator/ prey, parasite/ host; herbifory

-mutualistic: both benefits; positive relationship; wasp/ fig

-Multiple species interations- mimicry: immitate for protection

Evolutionary Arms Race

astructure that a prey creates (a poison) and a predator creates aresistance; cause/ effect; refers to predator/ prey (antagonistic) relationship

Secondary Compounds

herbivory; protection of plants from animals/ insects (i.e. poison toxin)


species gains protection frompredators from their resemblance to one another; copying other organisms;usually closely related species (coevolutionaryresponse)$t

Batesian Mimicry

-most common

-harmless sp (mimic) resembles harmful sp (model)

-theylive sympatrically w/one another: 1 species (safe 1) gets proection fromother (harmful 1)

-themimic has the same warning signs (colouring,pattern etc) asthe model but lacks the actual defense (chemical, spines etc)


whenthe both the mimic and the model have the same warming signs and the samedefense mechanism.N