Exam 2 Flashcards
(160 cards)
1
Q
what mechanisms can evolution (change in the genetic composition of a population over time) occur through?
A
-natural selection
-artificial selection
-genetic drift (random chance)
2
Q
what is the definition of natural selection?
A
a change in the frequency of genes in a population throughout differential survival and reproduction of individuals that possess certain phenotypes (outward expression of environmental effects on an organism’s genotype)
3
Q
_____ is a molecule composed of two strands of nucleotides that are wound together into a double helix
A
Deoxyribonucleic acid (DNA)
4
Q
what are chromosomes?
A
compact structures consisting of long strands of DNA wound around proteins
5
Q
what are genes?
A
regions of DNA that code for particular proteins; changes in some phenotypes are affected by a single allele (blood type).
6
Q
what are alleles?
A
different forms of a particular gene. changes in alleles can create differences in an organisms’ phenotype.
7
Q
most ecologically relevant traits are _______, meaning that a single trait is affected by several genes; this leads to continuous variation (fur color, body size).
A
polygenic
8
Q
describe what the differences between diploid cells and haploid cells are
A
diploid cells contain 2 sets of complete chromosomes. zygotes are diploid (2n) cells
(contain pairs of homologous chromosomes) somatic cells are all diploid and divide via mitosis.
haploid cells contain only one set of chromosomes. gametes are always haploid (1n) cells. formed by meiosis.
9
Q
what is random assortment?
A
haploid gametes are made by re-shuffling and independent assortment of genes as DNA is copied during meiosis; the combination of alleles in a given gamete could be any combination of those possessed by the diploid parent.
10
Q
what are mutations?
A
random, permanent changes in DNA (deletion, insertion, + substitution). mutations are rare but the more genes that a species carries, the more likely it is to occur.
mutations can be:
1) silent (do not change protein coding region)
2) deleterious/fatal
3) beneficial/better suited to local environment (randomly, not “by design”)
11
Q
traits that ______ fitness of an individual are passed to subsequent generations at _______ ________.
A
increase, higher rates.
this changes genetic makeup of populations over time
12
Q
explain how antibiotic resistance in humans can be problematic
A
with an increase in the amount of or dosage of antibiotics taken by humans, we’re seeing more and more antibiotic resistance (superbugs), and this is problematic because we can no longer fight off bacterial infections like tuberculosis.
13
Q
what is recombination?
A
the reshuffling of genes that can occur as DNA is copied during meiosis and chromosomes exchange genetic material. recombination helps the immune system rapidly evolve.
14
Q
during meiosis, pairs of homologous chromosomes can exchange DNA in a process called _________ _____
A
crossing over
15
Q
explain evolution through natural selection
A
an alleles’ beneficial or harmful effects influences an individuals’ probability of having offspring. these traits are selected for or against and lead to adaptations.
16
Q
explain evolution through random processes (genetic drift, bottleneck affect, or founder effect)
A
changes in allele frequencies happen by chance (adaptive value of allele is irrelevant); random subsets of individuals (with lower genetic variation) produce the next generation.
17
Q
explain how evolution by natural selection has affected fish eye size
A
fishes of the same species living deeper in caves had much smaller eye sizes because they couldn’t see light deep in the cave. fish living closer to the surface of the water had much larger eyes because they were able to see a lot more light.
18
Q
what is genetic drift? where is this the most common?
A
genetic variation is lost due to random variation in mating, mortality, fecundity, and inheritance. genetic drift is most common in small populations because random events can have a disproportionately large effect on the frequencies of genes.
19
Q
what is bottleneck effect?
A
a fairly diverse populations experiences a fatal event or catastrophe, and this causes only a few individuals to survive. this new population has significantly lower genetic diversity than the original population and will continue to be suspectable to issues caused by genetic drift.
20
Q
bottleneck effects can _______ a population from ________ to future environmental changes, such as an emergent disease.
A
prevent
adapting
21
Q
what is the founder effect?
A
when a small number of individuals leave a large population and colonize a new area, hence resulting in a new population with only a small amount of genetic variation. genetic variation remains low until enough time has passed to accumulate new mutations.
22
Q
provide examples of both the founder effect and the bottleneck effect
A
bottleneck effect ex: in Illinois the greater prairie chicken population declined from 12 million to 72 birds after the 1960s.
founder effect ex: water hyacinth from South America invaded many parts of the world and 80% of these populations contain a single genotype.
23
Q
stabilizing selection favors _______ ________.
directional selection favors _______ _______. disruptive selection favors _______ ________.
A
average traits.
one extreme.
both extremes
24
Q
what type of selection would be the most likely to lead to speciation?
A
disruptive selection
25
what is microevolution?
change in allele frequencies that occurs over time within a population. this change is due to different processes: mutation, selection, gene flow, and genetic drift.
26
what is macroevolution?
evolution at higher levels of organization including species, genera, families, orders, and phyla
27
what occurs faster: macroevolution or microevolution?
microevolution; occurs over a relatively short period of time compared to macroevolution
28
what is artificial selection?
humans decide which individuals will breed; breeding is done with a preconceived goal for the traits in a population.
29
what is an example of artificial selection
wild mustard has been bred to create broccoli, kale, cauliflower, cabbage, brussels sprouts, and kohlrabi
30
natural selection is an ecological process with an __________ _________
evolutionary script; individuals interact with their environment and traits that lead to greater fitness in an environment are passed on.
31
_______________ is a phenomenon in which industrial activities cause habitats to become darker due to pollution; individuals possessing darker phenotypes are favored by selection.
Industrial melanism.
32
provide an example of industrial melanism
during the 19th century, peppered moths were white with black spots but soot pollution blackened trees that the moths rest on during the way, hence causing the white moths (on black trees) to be readily seen and preyed upon, so blacker moths were selected for. (this has reversed as pollution has decreased)
33
what is speciation?
the evolution of new species
34
what are phylogenic trees?
hypothesized patterns of relatedness among different groups such as populations, species or genera; they depict which groups evolved from other groups
35
draw out the phylogenic tree of vertebrates including the traits inherited
lampreys --> cartilaginous fishes --> bony fishes --> lungfishes --> amphibians --> reptiles (including birds) --> mammals
36
what is allopatric speciation?
the evolution of new species through the process of geographic isolation. occurs when a single population is separated by a geographic event (formation of a river). the isolated populations experience genetic drift and the populations evolve separately until they become so different that they cannot interbreed. (considered the most common mechanism of speciation)
37
what is sympatric speciation?
the evolution of new species without geographic isolation.
ex: Cichlid fish in Lake Tanganyika have evolved into 200 unique species from a single common ancestor. species include mollusk eaters, fish eaters, and insect eaters (facilitated by distinct types of food resources in different habitats throughout the lake)
38
what is a polyploid?
a species that contains three or more sets of chromosomes.
39
polyploids arise when homologous chromosomes fail to separate during _______, producing diploid gametes. if a diploid egg is fertilized by a ______ gamete, a polyploid will develop.
meiosis
haploid
40
a polyploid is _____ to breed with a diploid and is genetically __________ from its parents. this can give rise to sympatric speciation.
unable
distinct
41
do polyploids occur in both plants and animals?
yes. polyploid plants tend to produce larger flowers and fruits.
42
provide examples of key innovations produced by evolution
-the evolution of winged mammals, enabling them to catch flying insects and collect nectar from flowers
-the evolution of C4 and CAM photosynthesis allowing flowering plants to grow in regions with scarce water
-selection on wing morphology along treehoppers produced distinct horns that serve a wide variety of functions, such as camouflage, defense and mating.
43
what is a tradeoff in allocation?
how an individual invests its time and energy between growth, reproduction, and survival for maximum fitness. driven by extrinsic (ecology) and intrinsic (physiology, phylogeny, and development) factors
44
what are the four life history traits of an organism?
-fecundity
-parity
-parental investment
-longevity/life expectancy
45
_______ is the number of offspring per reproductive episode
fecundity
46
______ is the number of reproductive episodes
parity
47
_______ _________ is the time/energy caring for offspring
parental investment
48
variation in one life history trait is often _________ with variation in another life history trait.
correlated. ex: the number of offspring is negatively correlated with the size of the offspring.
49
describe what "slow life history" or k strategy is. provide examples
long time to sexual maturity, long life spans, low numbers of offspring, high parental investment, traits that increase competitive ability.
examples: emperor penguins, elephants
50
describe what "fast life history" or r strategy is. provide examples
short time to sexual maturity, short life spans, high numbers of offspring, little parental investment, traits that increase population growth rate.
examples: krill, fish
51
rare plants are more likely to become extinct than more common species =
threat to biodiversity
52
___________ _____________ investigates ways to preserve, restore, and maintain biotic diversity in the face of human exploitation of natural ecosystems
conservation biology
53
what are some natural risk factors?
-population isolation
-specialization to a particular soil or rock substrate
-specific mutualistic relationships with other organisms
-genetic self-incompatibility
-difficulty in colonizing fragmented habitats
54
what are some human causes of rarity?
-loss of habitat
-loss of pollinators
-collecting for horticulture
-introduction of pests, competitors, and pathogens
55
describe r-selection in plants. provide an example
found in variable/unpredictable environmental conditions. life cycle is short and leads to high productivity, population size is highly variable. density-independent competition.
examples: dandelions
56
describe k-selection in plants. provide an example
fairly consistent and/or predictable environmental conditions. long life cycle and leads to efficient production, density-dependent competition.
examples: oak trees
57
the _______ within a plant community can be very different from that outside. temperature, humidity, soil moisture and light are ______.
microenvironment
modified
58
a stable community consists of _____ species whose seedlings can survive to maturity in this unique environment. (seedlings of species from other communities are at a disadvantage and cannot normally invade)
k-selected
59
if the stable community is removed by some _________, the soil ______ is exposed, and the microenvironment has changed.
disturbance (landslide, storm, fire)
surface
60
the first species to colonize the site after the disturbance are seedlings of ______ ________, adapted to open sites. this change in communities is called __________ ____________
r-selected species
secondary succession
61
many community traits change to make the community more ______, the cycles of energy and nutrients more _______, and the microenvironment less ________ (progressive succession).
complex
efficient
stressful
62
draw or describe Grime's triangle
competitors (top, increasing competition) (ex: goldenrod)
ruderals (right, increasing disturbance) (ex: Canada thistle)
stress tolerators (left, increasing stress) (ex: wooly lousewort)
63
what are competitors?
individuals that grow rapidly to a large size, have large units of construction and produce large seeds
64
what are stress-tolerators?
individuals that are robust, conservative, slow growing, but some species can gradually grow quite large with longevity.
65
what are ruderals?
individuals that have a (ephemeral) very short life cycle with a large proportional investment in reproduction relative to the mass of the individual.
66
Ruderals are usually __ ________ and competitors and stress tolerators are usually __ _______
r-selected
k-selected
67
what is the largest plant seed?
Coco de Mar (Seychelles)
length: 30cm
weight: up to 40 lbs.
(seeds tend to have a tradeoff between their size and the number of seeds produced)
68
what is the smallest seed?
Comet orchid
length: .05mm
weight: ~.02g
69
describe intraspecific (within species) and interspecific (among species) in terms of plant seed number vs. size
both: plants that produce larger seeds produce fewer and plants that produce smaller seeds produce more.
70
describe the tradeoff between offspring number vs. parental care
as the number of offspring increases, the amount of parental care per offspring decreases and reduces the chance for offspring survival.
71
provide an example of a study conducted demonstrating the tradeoff between offspring number and parental care
researchers manipulated the number of eggs per parent in magpie birds and they found that when they added eggs to the nest this resulted in lower offspring survival because competition among chicks caused slower growth and higher mortality.
72
describe the tradeoff between parental care vs. parental survival
having more offspring can stimulate parents to hunt harder for food to feed their offspring. this additional effort can negatively affect their parents' fitness.
73
provide an example of a study conducted demonstrating the tradeoff between parental care and parental survival
researchers added, removed and didn't change the number of eggs in kestrel nests and found that the increased hunting effort of kestrels with enlarged nests lowered adult survival into the next breeding season and reduced chances of future offspring.
74
describe the tradeoff between growth rate vs. fitness
delaying sexual maturity allows an individual to grow large and produce more offspring per year once reproduction begins. the age of sexual maturity is positively associated with the number of years an animal will survive after reaching maturity.
75
_________ growth is when individuals do not grow any more once reproduction begins; occurs in many birds and mammals
determinate
76
__________ growth is when individuals continue to grow after reproduction begins; occurs in many species of plants, invertebrates, fish, reptiles and amphibians
indeterminate
77
________ is when an individual reproduces once and then it dies. "big bang" (ex: agave)
Semelparity
78
_______ is when an individual reproduces multiple times. "bet hedging" (ex: yucca)
Iteroparity
79
where do semelparous varieties live?
live in wetter regions, but prone to fire, which may favor a single, large reproductive effort before fires kill adults. tend to be predictable environmental conditions.
80
where do iteroparous varieties live?
where there is less precipitation, but less chance of fire.
81
differences in breeding patterns lead to tradeoffs in ______ and ____ numbers, and in germination rates
fruit and flower
82
what is an example of an animal that is semelparous?
periodical cicadas spend 13 or 17 years underground as nymphs and then emerge from the ground in synchrony to mate. cycles of tree flowering and senescence may provide a cue for time until emergence. synchronous emergence is likely a strategy to overwhelm potential predators.
83
what is senescence?
a gradual decrease in fecundity and an increase in the probability of mortality.
84
senescence is an inevitable consequence of....
natural wear and tear. long-lived species appear to have better mechanisms for reducing the reproduction of reactive forms of oxygen and repairing damaged DNA and protein molecules
85
how do plants get super old?
they grow very, very slowly
86
what is a photoperiod?
the amount of light that occurs each day; provides a cue for many events in the life histories of virtually all organisms. photoperiod is related to decline of temperatures below a hospitable threshold.
87
fluctuations in resource availability often determine the ______ of life history events.
timing
88
_______ can affect many life history traits (time to and size of hatching, metamorphosis, and sexual maturity)
predation
89
provide an example of how predation affects life history traits in freshwater snails
freshwater snails face higher risks of predation when they're smaller, so when predators are present the snails delay reproduction to grow larger before reproducing. once the predator-induced snail begins reproducing, they can produce more eggs in each clutch because they have larger bodies and they can live longer.
90
_______ ________ impose strong selection and have substantial impacts on species' life history.
human activities (commercial fisheries impose selection pressure on fish size by harvesting only the largest of individuals. the average age at maturity of Arctic cod has decreased from 9-11 years to 7-9 years. this shift is likely associated with changes in in fecundity and longevity.)
91
phenological responses to climate change vary among ______
taxa (bird populations have declined by 90% where food for nestlings' peaks too early in the season)
92
what is asexual reproduction? how does it occur?
process that produces genetically identical offspring.
-a piece of the body gets separated
-commons forms are budding, fragmentation, fission, parthenogenesis, vegetative propagation, and spores
93
what is sexual reproduction?
produces a genetically different offspring
-male sperms fertilize female eggs (haploid) to form a zygote (diploid) that contains a combination of both parents' chromosomes.
94
what is the dilemma of having sex in animals?
a population of asexual females can grow twice as fast as populations that reproduces sexually yet most plants and animals procreate via sexual reproduction
95
what are the costs of sexual reproduction?
-sex organs are costly
-mating behavior can be risky (finding and attracting a mate is an energy/time investment, during mating you're vulnerable
-cost of meiosis
96
explain the costs of meiosis
compared to asexual reproduction, there is a 50% reduction in the number of a parent's genes passed on to the next generation (occurs because gametes are both haploid (1n))
97
what are the 4 main benefits of sexual reproduction?
-purging (getting rid of) mutations
-genetic variation helps cope with environmental variation
-biparental offspring care (k-selected species especially)
-coping with parasites ("co-evolutionary arms race")
98
what is the red queen hypothesis?
For an evolutionary system, continuing
development is needed just in order to
maintain its fitness relative to the systems it is co-evolving with.” (Leigh Van Valen (1973))
99
what does the red queen hypothesis predict?
sexual reproduction (genetic combination) allows hosts to evade parasites, which are coevolving - at a faster rate - to infect them. asexual reproduction increases susceptibility to infection.
100
what does the red queen hypothesis "arms race" mean?
sexual selection allows hosts to evolve at a rate that counters the rapid evolution of parasites. hosts and predators/parasites are engaged in an evolutionary "arms race" - evolving defenses (hosts) and overcoming defenses (parasites) just to maintain fitness.
101
what is an example of the red queen hypothesis that demonstrates an evolutionary race between parasites and hosts?
P. antipodarum snails in shallow water can be infected with trematode worms. in shallow waters, more snails use sexual reproduction than snails in the deeper waters because experiments demonstrated that trematodes were better at infecting shallow water snails than deep water snails.
102
most vertebrates and some plants have distinct separate sexes; most plants and some vertebrates are ___________
hermaphrodites (have both male and female sexual organs)
103
for hermaphrodites, ______ occurs when an individual's male gametes fertilize its own female gametes.
selfing
104
what are costs of selfing?
-strong inbreeding depression cost
105
___________ should favor individuals that can also breed with other individuals, called __________
selection
outcrossing
106
when mates are available, individuals _________, when mates are unavailable, individuals ____________. self-fertilizing does not produce as many ______ offspring, but it is better than nothing
outcross
self-fertilize
viable
107
mixed mating can be in response to a lack of ...
resources in the environment
108
orange jewelweed plants increase rates of self-fertilization with more ________ because ...
herbivory because when herbivores consume leaves, plants must expend energy to grow new tissue = tradeoff with investment in nectar
109
what is the optimal outcrossing distance?
intermediate distances because this balances the risk of inbreeding with
1. dispersal to unsuitable habitats
2. mating with too distant of relatives
110
when can outcrossing be disadvantageous?
grasses found growing near a mine have high contaminate levels of zinc and those plants growing on that mine have a relatively high zinc tolerance versus plants not growing near mines have very low zinc tolerance. so, if those plants outcross, they will lower their ability to handle high zinc concentrations which will decrease their overall fitness.
(naked mole rats are an animal example)
111
in organisms with separate sexes, the sex ratio of male to female offspring is often _____ ___ _____ because...
one-to-one because sex is determined by inheritance of sex-specific chromosomes (XX and XY). the sex that possesses two different chromosomes will produce an approximately equal number of gametes with each chromosome.
112
in bees, ants and wasps how is sex determined?
sex is determined by whether or not eggs are fertilized. fertilized eggs which have two sets of chromosomes become females and unfertilized eggs become males.
113
_________ _____ _________ is when sex is determined largely by the environment; this is a type of phenotypic plasticity, where phenotype is sex.
environmental sex determination
114
___________-______________ ____ _____________occurs when the sex of an individual is determined by the temperature at which eggs develop; common in reptiles
temperature-dependent sex determination
115
provide an example of a reptile who has temperature-dependent sex determination
for the Jacky dragon, females result if eggs are incubated at low or high temperatures; both sexes result at an intermediate temperature. males produced at intermediate temperatures will have more offspring than males produced at low or high temperatures.
116
females can influence the sex _______ of their offspring
ratios. in red deer, male fawns are energetically expensive to care for and young mothers often cannot find enough resources. therefore, yearling mothers can selectively abort male embryos, this results in low male to female offspring ratio; older mothers produce a nearly even ratio of male and female offspring because they are able to obtain enough resources.
117
_________ __________ _______ is when the rarer phenotype in a population is favored by natural selection. in a population with uneven sex ratio, the rarer sex will compete with fewer individuals for breeding and the rarer sex will experience higher fitness
frequency dependent selection
118
what is local mate competition?
when competition for mates occurs in a very limited area, only a few males are required to fertilize all of the females, which leads to skewed sex ratios.
119
provide an example of local mate competition
mating among offspring occurs in a fig and is often limited to brothers and sisters. up to 90% of a fig wasps' progeny may be composed of daughters. since females can lay a fixed number of eggs whereas males can fertilize many females, mothers should produce just enough males to fertilize all females.
120
what is a mating system?
the number of mates each individual has and the permanence of the relationship with those mates.
121
a females' reproductive success depends on what?
how many eggs she can produce and mate quality
122
what does a males' reproductive success depend on?
on the number of females that he can fertilize
123
what are the four classifications of mating systems?
-monogamous (you only mate with one individual for life (emperor penguins))
-promiscuous (everyone reproduces with everyone, (flowers and plants especially))
-polygynous (one male mates with multiple females (elk))
-polyandrous (one female mates with multiple males (Western toads))
124
what is extra-pair copulation?
when an individual that has a social bond with one mate also breeds with other individuals. females use this strategy to obtain superior genotypes and produce offspring with more genetic variability.
125
what animals is extra-pair copulation commonly seen in?
birds; bluethroat chicks are commonly fathered through extra-pair copulation. the chicks bred through extra-pair copulation have a better immune response (measured by wind swelling in response to an injection of foreign material)
126
what is sexual selection?
natural selection for sex-specific traits that are related to reproduction; leads to a variety of differences between males and females.
127
primary sexual characteristics are traits...
related to fertilization
128
secondary sexual characteristics are traits...
related to differences between the sexes in terms of body size, color,
129
what is sexual dimorphism?
the difference in the phenotype between males and females of the same species (body size, courtship behavior)
130
________ ________ differences between sexes are common in animals; there has been selection for an increased number of gametes or an increase in parental care in one of the sexes
body size
131
when males compete for females, selection will favor the evolution of ________
weapons (antlers, leg spurs on chickens)
132
female preference for male traits relates to features that improve her fitness, such as ____________ ___________
material benefits (like high-quality territory)
traits may also provide nonmaterial benefits.
133
provide an example of animals that display female preferences for material benefits
male long-tailed widow birds have a half-meter long tail that is displayed in courtship rituals. males with shortened tails attract and breed with fewer females than males with lengthened tails. tail length has no material benefit to females.
134
what is the good genes hypothesis?
the hypothesis that an individual chooses a mate that possesses a superior genotype
135
what is the good health hypothesis?
the hypothesis that an individual chooses the healthiest mates (could be a combination of genes and resources)
136
what is an example of the good health hypothesis?
female gray treefrogs choose mates that produce long mating calls. call length is an honest signal of genetic quality; offspring of long-calling males grow faster because they spend more time feeding than offspring of short-calling males.
137
________ __________ ________ is when selection from preference of a sexual trait and selection for that trait continues to reinforce each other; continues until males run out of genetic variation
runaway sexual selection
138
what is the handicap principle?
the greater the handicap an individual carries, the greater its ability must be to offset the disadvantage of that trait (huge antlers on an elk)
139
provide an example of the runaway sexual selection
having parasites can affect male attractiveness and rock doves infected by mites have lower survival and growth and had missing feathers. females chose the more attractive, non-infected doves by a 3:1 ratio.
140
what are benefits on living in groups?
-group defense
-dilution effect
-feeding (easier to take down big prey in a group/pack)
-mating (male ruffs in a lek are able to attack more females)
141
what is the dilution effect?
reduced probability of predation to a single animal when it is in a group (school of fish)
142
what are the costs of living in groups?
-predation (parasites and pathogens can be predators) high population density can increase the rate of disease spread
-competition (tradeoff between benefits and costs in intraspecific (within-species) competition)
143
costs and benefits of group living should lead to _______ ________ ______
optimal group size (assuming genetic component) due to natural selection
144
list an example of a study that demonstrates optimal group size
there was a study conducted on baboons that measures 1. daily travel distance and 2. fecal glucocortoid (stress levels)
145
what are the four types of social interactions?
1. cooperation (both the donor and the recipient experience benefit)
2. selfishness (only the donor benefits and the recipient experience cost)
3. spitefulness (both the donor and the recipient experience cost) (only humans exhibit this)
4. altruism (donor experiences costs and the recipient experiences benefits)
146
what is direct fitness?
passing copies of genes to offspring
147
what is indirect fitness?
indirectly passing on copies of your genes by helping a relative improve its fitness (also called kin selection)
148
_________ _______ is direct and indirect fitness combined
inclusive fitness
149
what is the coefficient of relatedness?
probability that copies of a particular gene are shared by relatives
150
indirect fitness = B x r, what are B and r?
B = fitness benefit to a recipient relative
r = coefficient of relatedness between donor and recipient
151
what is C in the evolution of altruism?
C = direct fitness cost to a donor relative
152
B x r > C = ___________
C/B < r = __________
beneficial (will be selected for)
costly (will be selected against)
153
in turkeys, r = 0.42 (mix of full brothers (.50 and half-brothers (.25))
c = 0.9 (average offspring from solo males)
B = 6.1 (average offspring from dominant brother)
therefore, what is the indirect fitness?
what is the inclusive fitness?
6.1 x 0.42 = 2.6
0 + 2.6 = 2.6
0.9/6.1 < 0.42
0.15 < 0.42
154
what defines eusociality?
-several adults living together in a group
-overlapping generations of parents and offspring living together
-cooperation in nest building and brood care
-reproductive dominance by one or a few individuals, and the presence of sterile individuals
155
what is an example of eusociality?
leaf cutter ants ("earth's first gardeners")
-practicing fungiculture (agriculture) for 50 million years
-47 species of ant
-each ant species cultivates different strains of fungi (Lepiotaceae)
-obligate mutualism - food for ants, food and protection for fungus
156
leaf cutter ants harvest _______ of total leaf production in tropical rainforests
>17%
157
what are the different sterile castes of leaf cutter ants?
-defense
-foraging
-building
-trash removal
-offspring care
158
______________ system favors eusociality
haplodiploid.
observed in bees:
-workers are diploid females that are sterile (development stops before sexual maturity due to lack of food provided)
-queens are diploid females that are fertile (reach sexual maturity)
-drones are haploid males that are fertile (reach sexual maturity)
159
social behavior in animals is based on _________ and subject to __________ __________
genetics
natural selection
160
