Biol116 Lecture 7 (10/14) (10/15) (In class)

Fundamental Niche

Th range of abiotic conditions (e.g. temperature, humidity, salinity, under which a species can potentially persist.

• larger bc all conditions

Realized niche

The range of abiotic and biotic conditions under which a species persists in presence of competitors, predators, and pathogens

Geographic range

A measure of the total area covered by a population or populations of a species

Abundance

the total number of individuals in population that exist within a defined area. Pop. size.

Density

the number of individuals per unit area or volume

Relationship between population density and body size

density and body size are negatively correlated

• larger species = smaller density

Aspen rees produce ____

clones (genetically identical copies)

Census

counting every individual in a population

Survey

counting a subset of individuals in the population

Area and volume based surveys

• taking samples in some spots

Line-transact surveys

count the number of individuals observed as one moves along a line

Mark-Recapture method

• Capture, tag, release a subset of individuals in a population

• give marked individuals times to mix back into population

• capture a second sample of individuals, and note how many of them are marked

Different types of mark tags

• Toe clipping

• VI alpha tags

Mark and Recapture

N = MC / (R)

N

population size

M

number captured and marked

C (mark recapture)

number captured in 2nd sample

R (mark recapture)

number recaptured in 2nd sample

Dispersion

The spacing of individuals with respect to one another within the geographic range of a population

Clustered dispersion

Flocks, schools, etc.

Evenly spaced dispersion

Plants, crops, territorial sps.

Random dispersion

Independent of the position of others

Dispersal

the movement of individuals from one area to another

Dispersal can cause __

a geographic range to expand rapidly if a few eindividuals can disperse much farther than the average individual

Dispersal can also effect ___

population density

Population density can affect

dispersal

Ideal free distribution

• Individuals usually choose habitats that provide the most energy

Endemic

• animal is found in this area