Population Dynamics

habitat

the place where an organism normally lives

population size

number of individuals of a specific species that occupy a given area or volume at a given time

population density

number of individuals of the same species that occurs per a unit area or valume

dispersion

pattern of distribution in which a population exists - may be clumped, random or uniform

clumped dispersion

suitable living conditions often distributed in patches

clumped dispersion

individuals of a population are more concentrated in certain parts of the habitat

suitable living conditions are dispersed, mates are easy to locate in groups, limited seed/egg disperal

three reasons why clumped dispersion exists

random dispersion

occurs when environmental conditions do not really vary within a habitat and individuals are neither attracted nor repelled by other species members

random dispersion

individuals are neither attracted nor repelled by other species members

uniform dispersion

individuals being equally spaced throughout a habitat

uniform dispersion

occurs when individuals compete for food, breeding or nesting grounds

organism size, study area size

two things that the dispersion type depends on

quadrat

sampling frame that is used for estimating population size, frame can be real or virtual

quadrat

used for estimating size/density of small immobile organisms

mark-capture method

sampling technique by estimating population size and density by comparing the proportion of marked and unmarked animals that are captured in a given area

demography

study of growth rate, age structure and other characteristics of population

natality

birth rate in a population

mortality

death rate in a population

immigration

movement of individuals into a population

emigration

movement of individuals out of a population

fecundity

potential for a species to produce offspring in a lifetime

density-independent factor

factor that influences population regulation regardless of density

weather, climate

example of density-independent factor

competition

interaction in which both competing population lose access to a resource

interspecific competition

competition between members of different species

intraspecific

competition between members of the same population for resources

predation

interaction between predator and prey

beetles survive more because no frost and kill more pine trees

example of a density independent factor

herbivory

organism feeds on a plant

mutalism

relationship is mutually beneficial

parasitism

parasite benefits from the host while reducing the host's fitness in some way

competition

both organisms lose access to resources

commensalism

one oganism receives benefits from the other without damaging it

honey bee, flowers

example of mutalism

moss gets light and nutrients from tree while tree is uneffected

example of commensalism

specialist

feeds on just one type of food

panda

example of specialist

generalist

have braoding tastes and can adapt to different conditions

crows

example of gernalist

mimcry

form of defence where a species evolves an appearance that ressembles the appearance of another species

camouflage

organism mimics patterns of its environment

chemical defence

organism is chemically unattractive, by releasing notorious odours or concentrating poisnous chemicals

behavioural defense

passive (through hiding, freezing or playing dead) or active (fleeing, herding, using distraction displays)

symbiosis

one species has a physically close ecological association with another

cattle egrets eat insects that elephants flush out of grass

example of commensalism

quadrant

sampling area used for estimating population size

crude density

The number of organisms of the same species living within the total area of their entire habitat is best known as which of the following?

commensalism

After generations of domestication, sheep came to depend on humans for food, reproduction and protection. Humans could not support their populations without the readily-available supply of food. Ecologically, this relationship is best classified as which of the following?

ACTIVE defense

When attacked, the sea cucumber ejects its intestines. The predator attacks these allowing the animal an opportunity to escape. It will grow a new digestive system. This is an example of which of the following?

clumped dispersion

Which of the population dispersion patterns is most often found in natural populations?

quadrat sampling

most accurate method of determining size of stationary organisms

random

The population dispersion pattern in which organisms are spread throughout their habitat in an unpredictable manner is known as which of the following?

mobile

mark-capture samplings is the most effective method for WHAT

popular dynamics

study of changes in a population characteristics

density dependent

factor limiting population growth that has a greater impact as the density increases

predation

beneficial to one species, lethal to another

mutalism

lichen cannot survive without fungus and vice versa

commenalism

Barnacles attached to whales are an example of what?

ecological density

number of organism of the same species distributed within the usuable area of its habitat

clumped dispersion

prairie dogs live in isolated colonies - what is this an example of

predation, parasitism

TWO ecological relationships when a speies benefits and one is harmed

clumped dispersion

organism are densely grouped into areas of their habitat with favourable conditions

uniform dispersion

pattern when organisms are equally spaced throughout their habitat

INTRASPecific

competition that arises when two members of the same species rely on the same resources

dependent

is predation density independent or dependent