Eco 2

Age-specific mortality is defined as the

difference between the number of individuals alive for any age class and the next older age class

The California newt is found only in California. This is an example of a(n) ________ species.

endemic

As discussed previously, a drought in 1977 caused the medium ground finch population on the island of Daphne Major to crash. This is an example of

environmental stochasicity

When the conditions are favorable for a population at low density, such as when a species colonizes a new environment, population growth is typically

exponential

The population pictured here is experiencing

logistic growth.

Density dependence involves a ________________ feedback loop; the larger the population, the ____________ it grows.

negative; slower

Which of the following is not a feature of a population?

number of species

According to headlines like this one, what value of r would you expect for most insect populations?

r<0

What might be an unforeseen outcome of planting soybean plants at high densities in a field?

reduced seed production per plant

An individual that experiences a sex reversal during its lifetime is

sequential hermaphrodite

Look at the life table for the human hookworm. What kind of survivorship curve does this animal exhibit?

Type III

At least until the advent of modern medicine, human babies that were born too small or too large often died. Birthweight is an example of a trait that is under _______________ selection.

stabilizing

When individuals in a small population have difficulty finding a mate, this is referred to as

the Allee effect.

Sickle-cell anemia is an autosomal recessive disorder. Two phenotypically normal carriers (Rr) have a child. What are the chances that the child has the disease?

25%

Female jacanas gather harems of as many as five males, mate with them, and defend them against other females. Males incubate eggs and provide parental care. This is an example of

polyandry

Herd immunity occurs when

susceptible individuals are protected from the disease because there are so many immune people that many of the infected individual's contacts are "wasted".

Which factor might limit a species' distribution?

Suitable environmental conditions, Geographic barriers, Habitat destruction

Head circumference in humans is an example of

a quantitative trait

The fastest rate of population growth occurs when a population is

at half of carrying capacity

You trap rodents and mark them by snipping off the end of their tails. This is a traumatic experience for a rodent, so when you return to conduct your second sample, rodents that were trapped on the first sampling occasion are now "trap shy" - they're less likely to enter your traps than rodents that were not previously captured. How is this likely to change your population estimate?

You will overestimate the rodent population.

Under the logistic population growth model, as population size (N) increases, the per capita

birthrate decreases and death rate increases.

The K in the term K-selected species refers to

carrying capacity

The copperband butterfly fish is found exclusively on coral reefs in the Pacific and Indian Oceans. This species exhibits a __________________ distribution.

clumped

An age pyramid

depicts the age and sex structure of a population

You sample a sessile (non-moving) population in multiple quadrats and find that the variance among quadrats is significantly greater than the mean abundance. You can conclude that

the population is clumped.

Plants use ________ methods of dispersal; animals use ____________ methods of dispersal.

Passive; passive or active

Which of the following is a density-independent factor

weather event

Mask-wearing and social distancing affect which parameter in the SIR model?

β

The flu has an R0 value around 2. What percent of us would need to be vaccinated to prevent an outbreak (assuming the vaccine is 100% effective)?

50%

In the diagram below, large circles represent hosts, and small circles and squares represent two different species of parasites in those hosts. How many parasite infrapopulations are pictured here?

8

Humans are a(n) ____________ species.

K selected

An organism has a high mortality rate at a young age, but those individuals lucky enough to make it through this vulnerable stage usually live a long time. What type of survivorship curve does this organism have?

Type III

A population has a net reproductive rate (R0) greater than 1. This population has an exponential growth rate (r)

greater than 0

An advantage to sexual reproduction is

increased genetic variability

As an individual ________ its reproductive effort, its survivorship usually __________

increases; decreases

Based on the previous slide, calculate R0 for the squirrel population. This population is

increasing

Polygamy

involves lasting pair bonds between individuals

A population of simultaneous hermaphrodites can (theoretically) produce ________________ as a population of sequential hermaphrodites.

twice as many offspring

In populations of territorial animals, or plants that compete intensively for belowground resources such as water or nutrients, the spatial distribution of individuals is usually

uniform

r-selected species

usually mature early and die young