Week Seven: Populations

distribution and abundance

The main goal of ecology is to understand the __________ and _________ of organisms

ecology

The study of how organisms interact with each other and their environment

Biotic Factors

living organisms (predators, competitors, etc.)

Abiotic factors

nonliving aspects (sunlight, temperature, humidity, water, etc.)

population

A group of individuals of the same species that lives in the same area at the same time, where it can tolerate abiotic environment

evolution

________ of new traits determine population growth or decline under local biotic and abiotic conditions

Population ecologists

___________ __________ ask questions about how and why the numbers of individuals in a population change over time

species

All populations, collective

size

Total number of individuals of all ages present at same time and in same area

range

area over which population is spread, driven by abiotic and biotic factors

density

size divided by range, can affect population size

random

in this distribution an individual has equal chance of occupying any position within range

plants

random distribution is normally seen in _____

clumped

in this distribution is seen in individuals grouped close together for safety or resources

meerkats

Clustered distribution is typically seen in _______

uniform

in this distribution is seen in individuals that may prevent from others being near by, and is more even than predicted by chance

count

How do ecologists measure size with sessile species?

mark and recapture

How to ecologists measure size with mobile species?

N = (C/R)M

What is the mark and recapture formula?

population size

What does N stand for in the mark and recapture formula?

total number caught

What does C stand for in the mark and recapture formula?

Number of marked recaptured

What does R stand for in the mark and recapture formula?

Marked on day one

What does M stand for in the mark and recapture formula?

N=(B-D)+(I-E)

What is the formula for population size changing with time?

change in population size/time

Rate of change of population size is given as:

Per capita growth rate (r)

Rate of population change divided by population size gives

Continuous

______ growth is when population increases or decreases continuously

discrete

______ growth is when population increases or decreases in steps

asynchronous

Species with ________ life cycles have continuous growth

synchronous

Species with ________ life cycle have discrete growth

synchronous

seeds germinating, growing, maturing, and then reproducing is an example of ________ lifecycle

asynchronous

being born and develop at different times like people, is an example of ________ life cycles

exponential

This formula is the equation for ________ growth

size, growth rate constant

Exponential growth is the simplest model as it assumes no constraints of ____, _______ ____ _______

Intraspecific

Competition for resources within species

interspecific

Competition for resources among species

Carrying capacity

(K) – max # of individuals habitat can sustain without degradation

S

Logistic growth produces and _ shaped curve

K

Logistic growth allows for _ to be displayed in the graph

Density-dependent factors

change in population related to size, due to competition (for food and other resources) and predation

Density-independent factors

change in population not related to its size

predict changes in population

Ecologists ______ _____ __ _______ using – 1) birth rate, 2) longevity of individuals, 3) proportion able to reproduce

age structure of population

divide population into age classes, structure allows predictions of growth

socioeconomics

Age structure of human populations partly driven by ___________

demography

study of size, structure, distribution of population

cohort

group of individuals born at the same time

Survivorship

proportion of individuals from initial cohort that survive each successive stage of life cycle

life table

This table shows number of individuals of cohort that are alive at different points

Survivorship

proportion of individuals from initial cohort that survives

Type I

What type of survivorship has high mortality at later stages

Type II

What type of survivorship has equal mortality throughout

Type III

What type of survivorship has high mortality at early stages

r

_-strategists are:

• unpredictable environment

• many young

• type III survivorship curve

• Reduce at rates approaching rmax

k

_-strategists are:

• predictable environment

• fewer young, larger, better-cared-for

• type I survivorship curve

• population commonly near carrying capacity

life history

typical pattern of resource investment in individuals to growth, maintenance or reproduction

Metapopulation

Collection of local populations, linked by corridors and movement between patches

Patch

Islands of habitat separated by uninhabitable corridors

vacant habitat

Metapopulation survives through recolonization of ______ ______

connected

When studying patches of moss that are connected and disconnected, the _________ patches survived better

island

any habitat patch surrounded by expansive inhospitable environment