Bio 303 Exam 3 Study Guide Questions

When can natural selection and sexual selection collide?

(see handouts) Natural selection and sexual selection sometimes act equally, but, generally, something has to give. Sometimes natural selection can act more strongly than sexual selection and vice versa. Example: flashy coloration may attract mates, but also attracts predators.

Know which of the major behaviors is a cost to "you" and a cost to "them"

Spite

What is infanticide?

New male comes in and kills all the infants from the previous male Seen in lions when new males take over a pride and kill all the cubs

What is siblicide?

One sibling kills another/weaker sibling -Baby eagle pushing its sibling out of the nest -spotted hyena -masked booby nestings

What are the conditions for eusociality?

Overlap in generations Cooperative brood care Specialized castes of non-reproductive individuals

What is meant by the vary phrase "Cambrian Explosion"?

One of the most important macroevolutionary events in the history of life Radiation that gave rise to many of the major groups of animals found on earth today, each with its own distinctive body plan About 520 and 530 million years ago many major taxonomic groups of animals appear for the first time in the fossil record Rise of DIVERSITY and new ecological opportunities

What has been the dietary shift of humans over the last 4 million years?

Originally had a diet that was rich in C-3 plants like fruits in leaves Acquired a C-4 signature in their teeth by eating the meat of grazing/grass eating animals

What is runaway sexual selection? What is an example?

Process by which a female's sexual selection for a trait in a male not necessarily used for survival (e.g. tail feathers in a peacock) may drive evolution until the trait is so exaggerated it is disadvantageous for the male. Proposed by Fisher. Tend to lead to extinction.

How does sexual selection influence human body size?

Sperm competition: Long penis, small sperm in large volume, large testes, large brain

What is stasis and what are examples?

Stasis is when lineages in the fossil record exhibit little or no directional change for millions of years Fossil gingko horseshoe crabs white-tailed deer

Examples of Stasis, punctuated equilibrium, and gradualism?

Stasis: -Fossil gingko -horseshoe crabs -white-tailed deer Punctuated equilibrium: -Bryozoans Gradualism: -tetropod body plan evolved gradually over time (Figure 4.22)

What is unique about C14 dating?

-Carbon-14 is continually generated in our atmosphere -Since it has a half life of 5730 years it can be used to determine ages of fossils less than about 50,000 years old very accurately -Plants and animals can both accumulate carbon-14 in bones and tissues

Why is female choice common, but male choice rare?

-Female choice is common because females rear the young and want to have a "good genes" and preferring certain males can result in a female gaining higher viability, fecundity, and reproductive success, for her offspring. -More often then not females are the limiting sex -Elephant for example long pregnancy span that is energy costly

What is Ediacaran fauna?

-Group of animal species that existed during the ediacaran period, just before the cambrian ---Between 575 and 535 million years ago -Ediacarans included diverse species that looked like fronds, geometrical disks, and blobs covered with tire tracks (probably fed by filtering seawater)

When does sexual selection act on females?

-If a males reproductive strategy lowers the fitness of females, then there will be a strong selection on females. And males then come under selective pressure to overcome female defenses resulting in a coevolutionary arms race. -Members of the sex subject to strong sexual selection will be competitive; members of the sex subject to weak sexual selection will be choosy. --Ducks for example: long penises; windy oviducts

What is characteristic of the K-T boundary?

-Iridium was found in high concentrations in the soil -Asteroid hit the earth -Quartz grains shocked by intense pressure -Quartz grains melted into glassy microtellities

Why is the burgess shale fauna significant?

-It yielded more than 65,000 specimens of mostly soft bodied animals representing at least 93 species --Fossils were preserved from the Cambrian period -It not only preserves the soft tissues of animals, but it also acts as a snapshot of an entire ecosystem that has long since vanished

What is the concept of the sneaker male? Examples?

-Male sneaks past other males that are typically more dominant in order to mate with female quickly -rather than getting access to mates by being larger than average and dominant, they are small enough to sneak past unnoticed. These 'sneakers' lead to disruptive selection acting on male size: large or small males will succeed by fighting or sneaking, respectively, while intermediate sized males will be unsuccessful at both strategies. Ex: =Seen in elephant seals (bachelor island of seals that lost battle over female) =Yellow throated side blotched lizards: mimic females to get passed orange throated " " that are big and aggressive to get into circle and mate with females

What are biomarkers

-Molecular evidence of life in the fossil record. -Biomarkers can include DNA, molecules such as lipids, or specific isotopic ratios -Amino acids produced by organisms abiotically 1. Whales fossil teeth: oxygen atom by water end up here and can indicate salinity of water (freshwater, intermidiate, or saltwater) 2. Okenane: derived from pigments of purple sulfer bacteria induced that oceans were toxic at this time period 1.64 billion years ago

What are haplodiploidy's conditions and what does this lead to?

Daughters are more closely related to each other (0.75) than to mother (0.5). --Its conditions coincide with eusociality, for example, ant colonies are eusocial AND haplodiploid: ---queen mates with one male to produce offspring ---females have higher inclusive fitness from helping mothers produce more sisters than they would if they reproduced themselves ---leads to colony where one female produces offspring with one male and female offspring are nonreproductive helpers

How can alternative male mating tactics influence which: disruptive selection, stabilizing selection, or directional selection?

Disruptive: sneaker male: Extreme phenotypes have higher fitness Stabilizing: Dominant male: Average phenotype has higher fitness Directional: Either of the phenotypes have higher fitness

What is cryptic female choice?

Female can exercise some influence over which males succeed by selecting sperm from among the males they have mated with. Arises after mating, when females store and separate sperm from different males and thus bias which sperm they use to fertilize their eggs. =Dryomyza anilis fly: Male performs courtship display after mating in the form of taps to ensure that the female uses his sperm to fertilize her eggs.

Who typically has higher parental investment? Males or females?

Females; certainty of paternity makes it hard for males to distinguish if the offspring is truly theirs or not; yolk rich gametes, females look for safe places to lay eggs or protect brood when they hatch, some animals keep their young inside their bodies

What is the difference between stasis and gradualism?

Gradualism defined: Selection and variation that happens more gradually. Very gradually over a long period of time, the population changes. Change is slow, constant, and consistent. Difference: Stasis: Species never changes Gradualism: Species change very slowly

What is the difference between group and individual selection

Group selection: is selection arising from variance in fitness among groups ==Ant colonies and bison herds Individual selection: describes selection arising from variance in fitness among individuals ==Successful males can transmit more copies of their alleles to subsequent generations

What is haplodiploidy?

Haplodiploidy: Mechanism through which sex is determined by the number of copies of each chromosome that an individual receives. Offspring formed from the fertilization of an egg by sperm (i.e. diploids) are female; those formed from unfertilized eggs (i.e. haploids) are male.

What causes helpers at the nest to evolve

Helpers evolve because of the benefits they receive such as: -Protection -skills needed when reproducing -helping kin (indirect fitness) -acquaint themself with future mates -acquire a a nesting territory

Why is being a helper at the nest the best of a bad situation?

Individuals forfeit all opportunities to reproduce themselves, but can be favored by selection when the relatedness among individuals is exceptionally high and the because of the indirect fitness benefits the helpers derive from their actions. =Helper male birds help males bring food to female = higher chance with mating if male dies or aquiring nest territory from breeders when they die. =In birds: typically happen when conditions are poor and odds are low for the young bird to successfully rear own.

When is male competition and combat expected?

Intrasexual selection: occurs when males are members of the less limiting sex and compete with each other over reproductive access to the female limiting sex

Define parental investment

Investing in the care, nourishment, or protection in offspring; means the energy and time expended in both constructing an offspring and caring for it.

Why is making the best of a bad situation an evolutionarily important concept

It increases indirect fitness of an individual (helper) and increases the direct benefits of the parent or dominant male/female

What are alternative male mating strategies and why do they exist?

Mate guarding to ensure the female uses their sperm; sneaking to mate with females and have a higher level of fecundity Example: -big strong fish vs small fast sneaker fish -Satellite male frog vs calling male frog

When is sexual selection stronger on males or on females?

Members of the sex subject to strong sexual selection will be competitive; members of the sex subject to weak sexual selection will be choosy.

What is punctuated equilibrium?

Model of evolution that proposes that most species undergo relatively little change for most of their geologic history. These periods of stasis are punctuated by brief periods of rapid morphological change, often associated with speciation

When did the big 5 mass extinctions occur?

The ordovician event (End Ordovician) Ended 443 million years ago The Devonian event (Late Devonian) Ended 359 million years ago The permian event (End Permian) Ended 252 million years ago The triassic event (End Triassic) Ended 200 million years ago The Cretaceous event (End Cretaceous) Ended 65 million years ago

What caused the cambrian explosion?

a. Dramatic changes to the ocean -Major rise in sea level due to tectonic activity -Levels of calcium in the ocean were raised -Oxygen levels in the ocean were raising b. The genetic toolkit enabled bilaterians to rapidly evolve into new forms to take advantage of all the ecological niches that were opening up

What is Hamilton's rule?

an allele for "altruism" will spread if Br>C and will not occur if Br< C (B=benefit to recipient, c=cost to actor, r=coefficient of relatedness). In other words, kin selection is more likely to spread when the benefits to recipient are great, cost to actor are low, and the participants are closely related.

What is female choice? Why and when does it occur?

-Intersexual selection -It occurs when females are the less limiting sex and can actively discriminate among males.

What is the difference between cooperation and reciprical altruism?

-Reciprocal altruism happens at different points over time, while cooperation happens at one point in time. -Cooperation occurs: Cooperation is the behavior by two or more individuals that leads to mutual benefit. -Altruism is the behavior that benefits another without benefiting oneself. -Reciprocal altruism fits in because it is the behavior that benefits another with the expectation that those benefits will be returned in the future. ==each individual interacts with the same set of indiviuals in a group ==Many opportunities for altruism occur in an individual's lifetime ==can be risky, sometimes you dont get it back

Which radioactive isotopes have the longest half life

-Samarium 147-Neodynmium143 (Longest half life) -Rubidium87-Strontium87 (Ideal for dating rocks)

What is sperm competition and what are examples?

-Some sperm is more successful =Seed Beetles: penises with sharp spines remove sperm from earlier male; longer spines=more successful when fertilizing =Primates: bigger testicles, hold more sperm=higher fertilization odds; larger in species with more females that can mate multiple males =Deer mice: sperm join together and swim faster and have kin recognition =Some species males linger around females after mating to keep other males away =Drosphilia: chemicals in semen to kill sperm of other males =Fly & beetle: inseminate with giant sperm =Male rate: mucus plug after mating

Define Sexual Conflict. Give examples.

-The evolution of phenotypic characteristics that confer a fitness benefit to one sex but a fitness cost to the other =Duck and waterfowls: due to harassment from males to mate ducks develop more flexible phalluses in males which results in more twisted and pocketed oviducts in females (arms race) =Drosphophilia: chemical warfare- toxic chemicals in semen= sick females= proteins to destroy some toxic protein in semen (Monogamy can stop this= relaxed selection) =Bedbugs: pierce body; inject with semen that swims to ovaries; sometimes they do this to other males as well to spread sperm =Water striders: Exhibit intense sexual conflict. Males jump onto females and grip them tightly to mate. Females respond by trying to flip the males off their bodies. Attacks reduce female's ability to exercise mate choice. Males that can overcome these counterattacks will have greater reproductive success.

Why is the coefficient of relatedness evolutionarily important?

-coefficient of relatedness: probability that homologous alleles in two individuals are identical by descent. -An alelle for altruism will spread if Br>c but will not occur if Br<c (Hamilton's rule)

Why does stasis occur?

-the environment the organism lives in does not change -the organism is developmentally constrained so that it can't evolve

What are the conditions needed for reciprocal altruism to occur?

1. Each individual repeatedly interacts with the same set of individuals in a group. 2. Many opportunities for "altruism" occur in an individual's lifetime. 3. Individuals have good memories (typically very intelligent) 4. Potential exist for altruistic interactions in symmetrical situation.

What are the costs of being social?

1. Increased conspicuousness to predators. 2. Increased competition for food 3. Increased competition for mates 4. Decreased certainty of paternity/maternity 5. Increased transmission of disease/parasites.

What are the benefits of being social?

1. Increased vigilance 2. Dilution effect 3. Enhanced defense capability 4. Cooperative foraging/hunting 5. Improved defense of critical resources

Why and how are naked mole rats eusocial without being haplodiploid?

1. Queen maintains control via intimidation, workers able to produce still will not 2. all members are hormonal diploids (2n) 3. each colony has 1 reproductive queen and 2 or 3 reproductive males 4. other workers are nonreproductive even tho they can reproduce 5. members are highly inbred (r=.81)

What can be said about ediacaran fossils?

1. Some of the fossils share many traits with living groups of animals ex: Kimberella -Had a rasp-shaped feeding structure found today in mollusks 2. Some fossils may be animals, but they are only distantly related to living lineages 3. Other fossils may be extinct lineages of different organisms that independently evolved multicellularity 4. Allow paleontologists to reconstruct entire ecosystems, infer how they functioned, track their change through time

When did the first evidence of animals occur?

1. Sponges appear to mark the earliest appearance of animals in the fossil record -650 million year old fossils 2. Findings suggest that animals had already evolved at least 100 million years before the start of the cambrian period

What are background extinctions?

The normal rate of extinction for a taxon or biota a. extinctions that are not part of mass extinction events b. thought to be due to typical types and rates of environmental change or species interactions as opposed to the extraordinary environmental changes that occur during mass extinctions

When did multicellular organisms first appear?

2.1 billion years ago

When did the first mammalian fossils appear?

About 150 million years ago

What is an adaptive radiation?

Adaptive radiations are evolutionary lineages that have undergone exceptionally rapid diversification into a variety of lifestyles or ecological niches

What is the relationship between adaptive radiations and mass extinctions?

Adaptive radiations follow mass extinctions

What is a Lagerstatten?

Are sites with an abundant supply of unusually well preserved fossils, often including soft tissues, from the same period of time -Burgess Shale is an example

When did photosynthesis first appear?

Cynaobacteria fossils show first signs of oxygen due to photosynthesis ~2.45-2.32 billion years ago

How are infanticide and siblicide adaptive behaviors?

These are adaptive behaviors because siblicide has evolved due to the uncertainty of survival or viability of offspring. Where infanticide is concerned, strategy is predominately an adaptive male behavioural strategy, to increase reproductive success in response to short term dominant male status within groups. The act of infanticide increases the males' chance of successfully siring offspring while they hold the 'dominant male' status. In other words: Siblicide is because killing a sibling increases individual fitness. Infanticide is because killing unrelated offspring increases individual fitness and male reproductive success

What triggers adaptive radiations?

Triggered by: 1. When clades evolve to occupy ecological niches in the absence of competition --1 or a few members of a small group of ancestral species rapidly diversifies in large numbers of descendant species occupy many niches b. When extinctions remove certain species from an ecological resource zone c. New adaptations known as key innovations evolve that allow them to occupy habitats or adaptive zones that were simply off limits to other clades --jointed legs of Cambrian Arthropods d. "Ecological Opportunity" ex: increase O2 levels and predation in Cambrian e. Island formation

When and why are sexual selection and natural selection at odds? Examples?

When female choice results in excessive phenotypic traits that can hinder the male's fitness. Coincides with runaway sexual selection =For example, populations of wild guppies that live in streams in Trinidad in the Caribbean have different color patterns depending on where they live. Male guppies living in streams that have a crayfish predator are drab green in color, but males living in streams that lack the crayfish predator have bright red tails. Apparently females prefer to mate with males with red tails, but in streams with a predator (the crayfish) that has good color vision, not enough red-tailed males survive to reproduce. =Peacock tails long and plummage and colorful due to female choice but hinder flight of peacock: sexual selection has Strong upper hand and is an example of the handicap principle =Female stalk eyed flies where females prefer males with long stalks =Great tailed Grackle: even sexual and natural selection =Scissor tailed flycatcher: sexual selection has upper hand over natural selection (wind on long tail) =Irish Elk: End result=extinction with the handicap principle =Red-Collared widowbird: longer tail= more nests, experiment done where the tails were cut off long tailed birds and glued on short tailed ones

When does sexual selection act on males?

When there is a greater variance for reproductive success

What does YOU and THEM really mean in terms of evolutionary biology

YOU = you and your kin THEM = those not related to you

Do humans exhibit sperm competitors or not? What evidence suggests sperm competitors?

Yes, Long penis, small sperm in large volume, large testes, scramble competition and multiple matings. However, Humans have low to intermediate levels of sperm competition when compared to the rest of the great apes

Game theory and examples

mathematical approach to studying behavior that solves for the optimal decision in strategic situations (games) where the payoff to a particular choice depends on the choices of others. -Game theory to model the evolution of behavior in populations -Side blotched lizards- 3 different males that look and behave differently ==Orange-throated males are bigger and aggressive and guard large territories containing multiple females. Blue-throated males are smaller and less aggressive than orange throats - they defend a territory but only big enough to contain a single female. Yellow-throated males don't defend any territory at all. Instead, they mimic female lizards (which also have yellow throats) in order to sneak into the territories of the other males. They can then surreptitiously mate with females, passing on their alleles for yellow throats and sneaky behavior. Their populations oscillate. Blue cooperatively excludes yellow sneakers, yellow sneaks copulations from orange usurpers, and orange usurp territories from blue mate-guarders.