Population density Flashcards
What are the 3 different types of population distribution and what type of interactions do they have
Clumped - positive (highly social, and join together to make it harder to be eaten)
Uniform - negative (territorial or fight for resources)
Random - Neutral (no resources to be fought over)
What is population size (N)
The number of species living in the same geographical area
What is density (Dp)
Number of species per unit of volume/area
What are the 3 ways to measure to population size
Quadrant - an area of a specific sized is used, the number of individuals in that area is counted. Best to use on big areas and for sessile organisms
Transect - Scientists walk along a rectangular line of a specific length and determine the amount of individuals of a species in that line. The starting point is selected randomly. Best to use on small patches of area and when the organism is easy to spot
Mark Recapture - Animals are caught, tagged, and released. Scientists compare the amount of animals and originally tagged, and the amount of animals come back tagged. Used with most animals because animals are always moving around
How is Mark recapture measured and what does each variable stand for
N = M x n/m
M = original # tagged
n = Total amount recaptured
m = total amount tagged after recapture
What is life history
The survivorship and reproductive pattern of an organism
What is fecundity
- The average amount of offspring a female produces in a lifespan and shows the output of energy
If a women is caring for the youth does that mean high fecundity or low
Low - She has to take of the youth first so does not have energy to reproduce right after
If a species reproduce and die does that mean low fecundity or high
High
What can affect fecundity
- The amount of time an organism takes to sexually mature
What is survivorship
Porportion of organisms that live to a given age in a lifespan
What are the 3 types of survivorships - explain
type 111 - have lots of young age deaths (most of the time before even being born) organisms produce more to compensate for the loss - High fecundity (salmon)
Type 11 - Organisms have a consent rate of death (chipmuck)
Type 1 - The young age group of these organisms live resulting in needing care - low fecundity (humans)
What are abiotic factors
Abiotic factors are density independent - dont stimulate growth because of the density
What are biotic factors
Factors that density dependent stimulate population growth because of the density
What are interspecific and intraspecific
Interspecific - competition between different species
Intraspecific - competition within a specific species
Predator prey relationship, what does it affect?
The predator-prey relationship is a density dependent factor that affects population size and is the reason why most species meet their carrying capacity
What is biotic potential
The per capita growth rate of a population
Carrying capacity
The maximum population a habitat can sustain
What does it mean if a graph has a j shape
There is growth in the population - insects, bacteria, small organisms
What does a s shaped graph mean
The growth is slow because of limited resources and rising competition ex. humans
What is r and k selected organisms
r - is used by organisms that live close to their biotic potential, they do not live long and do not care for the youth, sexually mature faster and reproduce more (higher fecundity) - seasonal plants, algae
k - used by organisms that live close to their carrying capacity of their habitat, live longer and sexually mature slower. Care for the youth so reproduce less ex. humans
