ENVS Quiz 2 lecture 4

¡Supera tus tareas y exámenes ahora con Quizwiz!

B.I.D.E.

(Births + Immigration) = (Deaths + Emigration)

population equilibrium equation

(Births + Immigration) = (Deaths + Emigration)

characteristics of k-strategists

- high energy per offspring - lower biotic potential - high recruitment - long lived - mature slowly - slow production - logistic population growth - live in stable environments

characteristics of r-strategists

- low energy used per offspring - high biotic potential - low recruitment - short life span/ mature quickly - rapid reproduction - short life span - opportunistic - exponentially growing population

factors hypothesized to decrease recruitment

- pollution - habitat alterations - predation - pathogens

if a population falls below its critical number

- surviving members become more vulnerable - breeding fails - extinction is almost inevitable

ecologists use population growth curves to determine:

1. how fast a population could grow 2. the population size now and in the future

K

Carrying Capacity

K-strategists survivorship

Type I

Population growth

a change in population size

constant population growth

adding a constant number of individuals over each time period - simplest type - not generally found in nature

Population growth rate

amount the population has changed DIVIDED by the time it had to change

density-dependent factor

any factor that increases with increased population density and decreases with decreased population density

density independent factor

any factor that is independent of population density

a population size depends on its

biotic potential and environmental resistance

reproductive strategies fall on a

continuum

top-down regulation

control of a population (species) by predation

bottom-up regulation

control of a population occurs as a result of scarcity of a resource

Population explosion

could occur under unlimited conditions, when organisms with a high r have rapid population growth (j-curve)

examples of density-dependent factors

disease, predation, food shortages

as population density decreases

environmental resistance decreases (population increase)

as population density increases

environmental resistance increases (population growth stops or decreases)

J-curve

exponential growth curve

exponential growth

growth at a constant RATE of increase doubling time remains constant

type I survivorship

high survivorship throughout life, especially early life

examples of type 1 survivors

humans

type II survivorship

intermediate survivorship throughout life

in the absence of environmental resistance you would get a

j-shaped curve

S-curve

logistic growth curve

environmental resistance can lower reproduction via

loss of habitat, pollution, changed animal migration patterns

type III survivorship

low survivor ship throughout life, especially early life

Carrying Capacity

maximum population of a species that a given habitat can support without being degraded over the long term

population density

number of individuals per area

example of r- strategists

ooysters

example of type III survivorship

ooysters

r-strategists react to change by becoming

pests

examples of BIOTIC environmental resistance

predators, parasites, competitors, lack of food

k-strategists

produce few young, but young are nurtured

r-strategists

produce lots of young, but leave their survival to nature

the two reproductive strategies are:

r and k

k-strategists react to change by becoming

rare or extinct

environmental resistance probably has greatest effects by affecting

recruitment

decreasing population

recruitment < replacement

constant population

recruitment = replacement

increasing population

recruitment > replacement

logistic growth

some processes slows growth so it levels off near carrying capacity

examples of density Independent factors

spring freeze, fire, pollution

example of type II survivorship

squirrels, birds

Recruitment

survival through early growth stages to become part of the breeding population

survivorship curves

survivorship curves are used to visualize how the number of individuals in a population decrease with time

environmental resistance

the combination of all biotic and abiotic factors that limit a population's increase

biotic potential (r)

the maximum number of offspring that can be produced under ideal conditions

r-max

the maximum rate at which members of a species can reproduce when conditions are unlimited

critical number

the minimum population base allowing the survival and recovery of a population

r-strategists survivorship

type III

abiotic and biotic factors cause mortality which prevents

unlimited population growth

examples of ABIOTIC environmental resistance

unusual temperatures, moisture, light, salinity, pH, lack of nutrients, fire, toxicants


Conjuntos de estudio relacionados

Prin of Entrepreneurship Test 1 - MindTap Questions

View Set

AP Human Geography Chapter 9 - Agriculture

View Set

ANS 105 Final Exam review (NCSU-AngeVH-2017spring)

View Set

Chapter 45: Caring for Clients with Disorders of the Upper Gastrointestinal Tract

View Set

California Legal Aspects of Real Estate Chapter 5

View Set