ecology exam 4 review

four characteristics of eusocial animals

1. adult animals living together in a group 2. overlapping generations of parents and offspring 3. cooperation in nest building and parental care 4. reproductive dominance by one or a few individuals and presence of sterile individuals

c) the jay should help its sister increase her brood size

a cooperatively breeding first-year Mexican jay could 1) breed on its own and produce an average of 0.88 young, 2) help its parents and increase their production by 0.60 young, or 3) help its sister and increase her productivity by 1.2 young; its r with the young of its parents = 0.42, and its r with the young of its sister = 0.38; which of the following is the most fit strategy for this bird? a) the jay should breed independently b) the jay should help its parents increase their productivity c) the jay should help its sister increase her brood size d) the jay should breed independently because breeding with one mate will be less stressful than helping family members, and this will probably result in a higher future survival rate e) the jay should forgo all breeding behavior during this first year, and focus on enhancing its survival and reproduction later in life

metapopulation

a group of isolated populations of a particular species that are interconnected by occasional interactions between populations and between individual organisms

habitat corridor

a narrow strip of quality habitat connecting otherwise isolated patches; promotes dispersal and helps sustain populations of particular species

dispersal limitation

absence of a population from a suitable habitat due barriers which prevent them from dispersing dispersal barriers can be large expanses of inhospitable habitat (such as oceans and deserts) or human activities (such as roads and walls) humans are able to overcome dispersal barriers and can introduce nonnative species to new habitats, such as how Aboriginal people brought dogs to Australia

age structure pyramids

age structure pyramids with broad bases indicate growing populations (more young than old individuals) age structure pyramids with straight sides indicate stable populations (equal young and old individuals) age structure pyramids with narrow bases indicate a declining populations (fewer young than old individuals)

altruism will be favored when the benefit given to a recipient relative (B) times the coefficient of relatedness between donor and recipient (r) is greater than the direct fitness cost to the donor (C)

altruism favored when B x r > C ex: cooperatively breeding young bird could breed on its own and produce an average of 0.88 young, help its parents and increase their production by 0.60 young, or help its sister and increase her productivity by 1.2 young; its r with the young of its parents = 0.42, and its r with the young of its sister = 0.38 for breeding on its own: B x r = 0.88 x 0.50 = 0.44 (r is 0.50 bc a parent contributes 50% of its genetic material to its offspring) C = 0.44 for helping a relative instead of breeding on its own for helping its parents: B x r = 0.60 x 0.42 = 0.252 for helping its sister: B x r = 1.2 x 0.38 = 0.456 thus altruism is favored and the young bird's best strategy would be to help its sister (bc 0.456 > 0.44)

d) 92

as a biologist you want to determine the population size of pikas on an isolated mountain in Colorado; you trap and mark 38 pikas during your first trap session; a week later, you capture 29 pikas, of which 12 have marks; what is the best estimate of the population size? a) 38 b) 67 c) 79 d) 92 e) 123

processes influencing a population's size and growth rate

births and immigration add individuals to a population deaths and emigration remove individuals from a population

census

complete count of every individual in a population of a particular species; generally not feasible

helpers at the nest

cooperative breeding in which one or more younger individuals help a breeding pair with parental care (often an adult offspring of the breeding pair); 80% of cooperative breeders; ex: florida's scrub jay, gray wolf, red-cockaded woodpecker, harris's hawk

population density and body size

density of a population is negatively correlated to the body size of the species ex: for herbivorous animals, smaller species live in higher densities (such as mice), while larger species live in lower densities (such as elephants); given a certain area, small species will be more abundant than large species

clustered dispersion

dispersion pattern in which individuals are aggregated into groups, usually because of social groups or clustering around resources (ex: elephants)

uniform (evenly-spaced) dispersion

dispersion pattern in which individuals maintain a uniform distance between themselves and their neighbors, usually because of defending territories (ex: songbirds)

random dispersion

dispersion pattern in which the location of each individual is independent from other individuals (ex: dandelions); not common in nature

queen

dominant, egg-laying female in a eusocial group; typically mates once; her sons are unfertilized eggs and her daughters are fertilized eggs (haplodiploid)

cooperation

donor and recipient of a social behavior both experience increased fitness from their interaction (ex: pride of lions kill prey together)

selfishness

donor experiences increased fitness and recipient experiences decreased fitness (ex: competition for food)

effects of global warming

during the past 50 years, the mean temperature of earth has increased by 0.8° celsius; temperature changes can cause a shift in the geographic ranges of different species

modeling invasive species

ecological niche modeling can be a useful way to predict the expansion of pest species introduced to a continent where they have not previously lived

growth rate

equals number of individuals born in a given time period (birth rate) minus number of individuals that die during same time period (death rate) growth rate = (birth rate) - (death rate) if birth rate is higher than death rate, a population's growth rate will increase if birth rate is lower than death rate, a population's growth rate will decrease

ecological constraints hypothesis

eusocial behavior can evolve when an individual has low chance of survival outside of their colony (constraints); thus because their is a low chance of successful direct fitness for an individual, it is better for them to emphasize indirect fitness by caring for their relatives

evolution of eusociality

eusociality has independently evolved many times; being haplodiploid favors the evolution of eusociality, but is not required

fitness

every interaction between two individuals (donor and recipient) has the potential to affect the ____ of both individuals, positively or negatively

cooperative groups

exhibited in more than 200 species of birds and in more than 120 species of mammals (overall about 3% of bird and mammal species)

comparing growth models

exponential and geometric growth models are identical, except exponential's e^r replaces geometric's λ e^r = λ → r = ln(λ) λ > 1 and r > 0 with an increasing population λ < 1 and r < 0 with a decreasing population λ = 1 and r = 0 with a stable population

exponential growth vs logistic growth

exponential growth occurs when a population's growth per capita (per individual) growth rate stays the same regardless of population size, making the population grow faster and faster as it gets larger; follows a J-shaped curve dN / dt = r N where: dN / dt = rate of change in population size r = intrinsic growth rate N = current population size at time t logistic growth occurs when a population's per capita (per individual) growth rate decreases as population size approaches the maximum number of individuals in a population which the environment can support, the carrying capacity dN / dt = r N (K - N/K) where: dN / dt = rate of change in population size r = intrinsic growth rate N = current population size at time t K = carrying capacity

density-dependent factors

factors related to a population's density that affect the population by causing their growth rate to increase or decrease; includes predation, disease, and competition for resources such as food, water, shelter, and sunlight

density-independent factors

factors unrelated to a population's density that affect the population by causing their growth rate to increase or decreases; includes habitat destruction, overexploitation by humans, and natural disasters

indirect fitness

fitness an individual gains by helping relatives pass on copies of their genes (donor and recipient have shared genes)

inclusive fitness

fitness an individual gains from the combination of direct and indirect fitness

direct fitness

fitness gained by parents passing on copies of their genes to their offspring

negative density-dependence

for most natural populations, there is a negative relationship between population growth rate and population density also simply called density-dependence population growth rate decreases as population density increases population growth rate increases as population density decreases occurs when population densities are high, which can increase predation, disease, and competition for resources such as food, water, shelter, and sunlight

positive density-dependence

for some natural populations, there is a positive relationship between population growth rate and population density also called inverse density-dependence or Allee effect population growth rate increases as population density increases population growth rate decreases as population density decreases occurs when population densities are low, which can make it harder to find mates; low densities can also lead to harmful effects of inbreeding, lack of genetic diversity, and risk of chance catastrophe

cosmopolitan species

general species that are found over a large area that can span throughout the earth

survivorship curves

graphs that represents the distinct patterns of species survival at different ages throughout their lives type I curves represents species whose young have high survivorship and most live until old age; tend to be K-selected species (ex: large mammals such as humans and elephants) type II curves represent species who have steady survivorship throughout their lives and die at all ages (ex: birds and small mammals such as mice) type III curves represent species whose young have low survivorship and most die at young age; tend to be r-selected species (ex: fishes, invertebrates, plants)

intrinsic growth rate (r)

highest possible per capita (per individual) growth rate for a population; maximized for individuals living under ideal conditions

population density

if ____ is greater than what the habitat can support, some individuals must disperse; higher density of individuals typically occurs near the center of their geographic range; habitat is less ideal near the edges of their range and thus density of individuals is lower

subpopulation connectivity of metapopulation

if the subpopulations of a metapopulation have low connectivity and dispersal, subpopulation sizes fluctuate independently if the subpopulations of a metapopulation have high connectivity and dispersal, the metapopulation functions as one large population if the subpopulations of a metapopulation have intermediate connectivity and dispersal, subpopulations can influence each other

c) it would represent a slightly increasing population or an r value slightly larger than zero

if λ is 1.0003 in a geometric growth model, how would this relate to r in an exponential growth model? a) this λ value would approximately correspond to an r of 0.997 b) this λ value would be indicative of a declining population or equivalent to a negative r value c) it would represent a slightly increasing population or an r value slightly larger than zero d) in an exponential growth model, this parameter value would equate to r = 1.003 e) actually, λ and r are totally unrelated

e) small subpopulations that are far away from the nearest adjacent subpopulation

in a metapopulation, which subpopulations are most likely to go extinct and remain unoccupied? a) large subpopulations b) small subpopulations close to another subpopulation c) large subpopulations far away from the nearest adjacent subpopulation d) subpopulations that are far away from the nearest subpopulation e) small subpopulations that are far away from the nearest adjacent subpopulation

d) lx is the probability of survival to age x; sx is the probability of surviving at age x

in life table analyses, what is the difference between sx and lx? a) sx is the probability of survival to age x; lx is the probability of surviving at age x b) there is really no difference, both are estimates of annual survival c) sx is the rate of survival times age; lx is longevity times age d) lx is the probability of survival to age x; sx is the probability of surviving at age x e) sx is survivorship at age x; lx is the probability of producing a litter at age x

b) two competitive species evolve toward or specialize in using resources of different sizes or in a different way to minimize direct competition

in natural ecosystems, how do two competing species most likely avoid the outcome of competitive exclusion? a) they don't, one species wins and the other goes extinct b) two competitive species evolve toward or specialize in using resources of different sizes or in a different way to minimize direct competition c) one species hides, until the other is gone, then goes and exploits its chosen resource d) one species becomes a herbivore and the other species becomes a carnivore e) the less-competitive species disperses to a new area, thereby completely avoiding the more-competitive species

a) it is the food intake rate of a predator as a function of prey density

in regards to predation, what is a functional response? a) it is the food intake rate of a predator as a function of prey density b) a functional response is the increase in predator reproductive output as function of an increase in the number of available prey c) it is the food intake rate of a predator regardless of prey density d) this describes the immigration of mobile predators into an area of high prey density e) the functional response of a predator is any counter adaptation that enables a predator to defeat a defensive tactic or adaptation of a prey

d) you employ this equation to calculate the number of individuals in the population at time t

in the equation Nt = N0 e^rt , what does calculating Nt tell you? a) Nt refers to the initial population size b) it indicates whether the population is increasing or decreasing c) Nt is the change in number per unit time d) you employ this equation to calculate the number of individuals in the population at time t e) you calculate this parameter to determine the intrinsic rate of increase of the population

indirect fitness benefit equals benefit given to a recipient relative (B) times coefficient of relatedness between donor and recipient (r)

indirect fitness benefit = B x r

donor

individual who directs a behavior toward another individual

recipient

individual who receives the behavior of a donor

caste

individuals within a eusocial group that share a specialized form of behavior

conspecifics

members of the same species

ideal free distribution

model which predicts how individuals will distribute themselves among habitats with varying levels of resource availability, such that they each live in a habitat that maximizes their fitness and minimizes their competition number of individuals that aggregate in each patch is proportional to the amount of resources available for that patch average gain rates are equal in all habitat patches more individuals aggregate in rich habitats with higher resource availability, but this increases competition less individuals aggregate in poor habitats with lower resource availability, but this decreases competition

eusocial animals

most ____ are insects, including bees, ants, wasps, and termites; only three animals other than insects are know to be eusocial, including a species of snapping shrimp, naked mole rats, and damaraland mole rats

dispersal

movement of individuals from one area to another mechanism by which individuals can move between suitable habitats; allows species to colonize habitats outside their geographic ranges; can be a way to avoid areas of high competition, lack of resources, or high predation dispersal can expand a species geographic range to quickly expand if a few individuals can disperse much farther than the average individual ex: lifetime dispersal distances were 344-1,681m for average leg-banded starlings; a few individual starlings disperse long-distance, which allow starlings to spread 4,000km in 60 years

natal dispersal

movement of individuals from their birth (natal) area to their first breeding area

endemic species

native species that are found within a particular area and nowhere else on earth

density

number of individuals in a population of a particular species per unit area or volume

coefficient of relatedness (r)

numerical probability of an individual and it's relatives carrying copies of the same genes from a recent common ancestor

c) type III

oak trees exhibit high mortality of seeds and seedlings, but once trees reach about 10 years of age, annual survival is very high (>90%); what kind of survivorship curves do oak trees exhibit? a) type I b) type II c) type III d) a combination of type I and II e) a combination of type I and III

non-reproductive progeny of a queen

offspring which gather food and care for young; unable to reproduce

sex-determination system (eusociality)

one sex is haploid and the other sex is diploid (haplodiploid); in bees, sons develop from unfertilized eggs (haploids) and daughters develop from fertilized eggs (diploids)

dispersion

pattern of spacing among individuals of a population of a particular species with respect to one another three patterns are clustered, uniform (evenly-spaced), and random

geometric growth model

population growth model in which a population increases at discrete intervals Nt = N0 λ^t where: Nt = future population size N0 = current (initial) population size t = time interval over which population grows λ = discrete growth rate lamda equals ratio of population's size in one year to its size in the year before (λ = N1 / N0) λ > 1 with increasing population λ < 1 with decreasing population λ = 1 with stable population λ cannot be negative

exponential growth model

population growth model in which a population increases continuously at an exponential rate Nt = N0 e^rt where: Nt = future population size N0 = current (initial) population size r = intrinsic growth rate t = time over which population grows e = natural log = 2.71282 exponential growth follows a J-shaped curve rate of a population's growth at any point is the derivative of the equation: dN / dt = rN r > 0 with increasing population r < 0 with decreasing population r = 0 with stable population

logistic growth model

population growth model which describes slowing growth of populations at high densities as the population approaches carrying capacity carrying capacity (K) is the maximum number of individuals in a population which the environment can support dN / dt = r N (1 - Nt/K) where: dN / dt = rate of change in population size r = intrinsic growth rate N = current population size at time t K = carrying capacity logistic growth follows an S-shaped curve inflection point is the point on a sigmoidal growth curve that a population has its highest growth rate

basic metapopulation model

population model in which there are patches of suitable habitat embedded within a matrix of unsuitable habitat all suitable patches are assumed to be of equal quality

source-sink metapopulation model

population model that builds upon the basic metapopulation model and accounts for the fact that not all patches of suitable habitat are of equal quality sources: high-quality habitats which can maintain their own subpopulations and are the origin of dispersers for sinks; reproduction is higher than mortality sinks: low-quality habitats which need incoming dispersers from sources to maintain their subpopulations; reproduction is lower than mortality

landscape metapopulation model

population model that considers differences in quality of the suitable habitat patches and differences in quality of the surrounding matrix surrounding matrix is composed of both the unsuitable habitat and habitat corridors that connect the suitable habitat patches it shows most realistic and most complex spatial structure for populations

geometric growth in nature

populations initially grow slowly because there's fewer reproductive individuals, then growth rate increases with the number of reproductive individuals most species have discrete breeding seasons, such as how birds and mammals in northern hemisphere breeding during the spring

population abundance and range

populations with higher abundance have larger geographic ranges; observed for many organisms may be related to resource availability implication: reduction in the range of a population, such as from habitat loss, will reduce the size of the population

ecological niche modeling

process of determining the suitable habitat conditions for a particular species

realized niche

range of abiotic conditions (such as temperature, humidity, and salinity) under which a particular species can actually survive, grow, and reproduce, due to presence of biotic conditions such as competitors, predators, and pathogens

fundamental niche

range of abiotic conditions (such as temperature, humidity, and salinity) under which a particular species can potentially survive, grow, and reproduce

ecological envelope

range of habitat conditions predicted to be suitable for a particular species based on ecological niche modeling

d) the population will likely continually fluctuate in numbers above and below K over the long term

related to delayed density dependence, if rτ is relatively large (>1.75), what pattern will a population likely exhibit? a) it will stabilize at carrying capacity b) the population will overshoot K, crash, and not likely recover c) the population numbers will exhibit damped oscillations d) the population will likely continually fluctuate in numbers above and below K over the long term e) the population will hit a stable limit and go extinct

self-thinning curve (plants)

relationship in which a decrease in population density over time leads to an increase in size of each individual plant

mark and recapture

sampling technique in which organisms are marked and (ideally) recaptured to provide an estimate of the entire population's abundance, density, birth rate, and death rate; useful for mobile organisms first event: capture part of a population, mark all individuals, and release them back to their habitat second event: recapture individuals, record number caught with and without marks, and estimate entire population size N = number in entire population (unknown!) M = number marked and released in first event n = number recaptured in second event m = number marked in second event M / N = proportion of entire population that is marked (unknown!) m / n = proportion of recaptured population that is marked if recaptured population is a random sample of marked and unmarked individuals, then it should represent a good estimation of proportion of entire population that is marked m / n = M / N → N = (M x n) / m ex: 109 trouts were captured and marked; few days later 177 trouts were caught, 57 trouts of which were marked 57 / 177 = 109 / N → (109 x 177) / 57 = 338 therefore there are about 338 trouts in the entire population

direct selection

selection that favors direct fitness

kin selection (indirect selection)

selection that favors indirect fitness

altruism (selflessness)

social interaction increases recipient's fitness and decreases the fitness of the donor (rare)

spitefulness

social interaction reduces the fitness of both donor and recipient (does not occur in natural populations)

demography

study of populations

area and volume based surveys

surveys that first define a sub-sample which is representative of an entire population's density, and then count all the individuals in the sub-sample P = number in entire population A = habitat area for entire population p = number in sub-sample a = habitat area for entire population if sub-sample is representative of the entire population's density, then its proportion could be used to estimate number of individuals in the entire population p / a = P / A ex: 6 jackrabbits were counted in a 10km^2 sub-sample area which is representative of entire population 6 / 10 = P / 150 → P = 90 therefore there are about 60 jackrabbits in a 150km^2 suitable habitat area for the entire population

apparent altruism

the idea that altruistic acts are actually cooperative; when an individual selflessly helps another individual, both the recipient and the donor benefit and receive increased fitness

b) uniform

the population of northern mockingbirds on UNT campus has what kind dispersion? a) clustered b) uniform c) random d) haphazard e) chaotic

geographic range

total area covered by a population of a particular species

abundance

total number of individuals in a population of a particular species that exist within a defined area

density-dependent factors and density-independent factors

two general types of factors that affect populations by causing their growth rates to increase or decrease

e) life table analysis can be used to determine the population patterns and parameters described in answers B, C, and D

what good are life table analyses? a) they are a waste of time b) they can be used to determine if a population is increasing or decreasing c) they can be used to calculate λ d) they can be used to estimate the generation time of a population e) life table analysis can be used to determine the population patterns and parameters described in answers B, C, and D

c) the actual space that an organism inhabits due to biotic constraints (competitors, predators, human activities) and other constraints (environmental conditions, food availability)

what is the realized niche of a species? a) the full range of abiotic conditions in which a species can exist b) where the species may hypothetically be found in the environment c) the actual space that an organism inhabits due to biotic constraints (competitors, predators, human activities) and other constraints (environmental conditions) d) the location where a species has access to suitable resources and can successfully reproduce e) it would include all the locations where an ecological niche model predicts that a species should occur

subpopulations

when a large population of a particular species is broken up into smaller groups that inhabit isolated habitat patches a metapopulation exists when individuals frequently disperse among subpopulations if dispersal is infrequent, each subpopulation fluctuates independently

cooperative breeding

when one or more individuals help care for young that are not their own; helpers are altruistic because they benefit others while incurring costs to themselves

e) the mesopredator population explodes adversely impacting many beneficial native species

when top predators are removed from an ecosystem, what often happens? a) the ecosystem becomes more productive and provides benefits to the human population b) prey populations increase to carrying capacity and stay at the level in harmony with their available resources c) prey populations often increase above carrying capacity and destroy their habitat d) mesopredators take over the role of top predators and control populations of prey e) the mesopredator population explodes adversely impacting many beneficial native species

e) all of the above answers could explain an observed apparent act of altruism

which of the following could explain the observation of an apparent altruistic act by a donor animal to recipient of the same species? a) the donor could be helping a relative (kin selection) b) this could be an example of cooperation c) this could be a case of reciprocity (reciprocally exchanged "help") d) perhaps, the recipient has deceived the donor into helping the recipient (deception) e) all of the above answers could explain an observed apparent act of altruism

b) a hurricane

which of the following is a density-independent limitation to population growth? a) predation b) a hurricane c) the amount of available food resources d) the amount of suitable nest sites e) the number of territorial spaces available

b) a red-tailed hawk defending its nesting territory from conspecifics

which of the following is an example of interference competition? a) squirrels and blue jays consuming acorns from an oak tree b) a red-tailed hawk defending its nesting territory from conspecifics c) beavers and deer eating young willow trees along a stream d) quail and kangaroo rats foraging on seeds in a desert arroyo e) none of these are examples of interference competition

e) both B and D are correct

which of the following is true about the Lotka-Volterra model? a) they involve a series of equations that demonstrate that predator populations will cause prey populations to stabilize at K b) the Lotka-Volterra model shows how the interaction of one population of predators with one population of prey could result in non-synchronous regular oscillations in both populations c) the Lotka-Volterra equations prove how a predator population can cause the extinction of a prey population d) the Lotka-Volterra model involves 2 simultaneous equations, one estimating the number of preys and the other estimating the number of predators at any given point in time e) both B and D are correct

d) a slowing in the rate of genetic change

which of the following likely will not be a response of biota to climate change? a) a shift in range toward the poles b) earlier timing of spring events such as breeding season c) extinction of species when range shifts and adaptation fail to keep pace with environmental change d) a slowing in the rate of genetic change e) adaption to a changing environment

d) Leon Springs pupfish

which of the following species is endemic to Texas? a) white-tailed deer b) bald eagle c) red-tailed hawk d) Leon Springs pupfish e) American bison

d) the recipient gains a fitness benefit and the donor experiences a fitness loss from the interaction

which statement below is an example of true altruism? a) both the donor and recipient receive a net fitness benefit from the interaction b) the social interaction reduces the fitness of both the donor and recipient c) the donor receives a fitness benefit while the recipient has a fitness loss d) the recipient gains a fitness benefit and the donor experiences a fitness loss from the interaction e) the fitness of the donor is enhanced while the fitness of the recipient is not affected

c) an optimal forager should always go to the patch with the most resources

which statement is false about Ideal Free Distribution (IFD)? a) the resources available to each individual animal in a patch will decrease as the number of competitors increase b) with IFD, all competitors should distribute themselves among patches to achieve equal per capita benefits c) an optimal forager should always go to the patch with the most resources d) the numbers of competitors in a patch should be directly proportional to the "resource input rate" e) IFD could explain the distribution of males among patches if the resource of interest was the numbers of ovulating females found in patches