Biology C4.1

define population

a group of organisms of the same species living in an area at the same time

define community

A community comprises several populations of organisms living and interacting with each other.

how is quadrat sampling calculated

average # x total area = estimated population size

what organisms are quadrat sampling used for 

sessile organisms 

define climax species

species that has been sustained for a long period of time in a specific ecosystem

describe to me high vs low standard deviation

high= uneven population distribution

low= even population distribution

how to calculate capture-mark- release-recapture

M = number of individuals marked

N = total # caught in the 2nd sample

R = # of marked individuals captured

M*N/R

this is the observed table can you calculate and determine if species r independent (randomly distributed) or associated, define what test this is

chi-squared test

what is the carrying capacity

the maximum population size that a given environment can sustain over a certain period of time

what is a density dependent factor and what makes it so important

density dependent factors

have different effect at different population densities

eg. predation, disease
density-dependent factors tend to act to keep a population at or below its carrying capacity; this is a negative feedback effect

what do you call an interspecific reaction between HIV and humans 

Pathogenicity involves the organism/virus living and reproducing in the host organism and causing negative impacts on the likelihood of survival.

what do you call the types of symbiosis relationship between 1. Barnacle and whales 2. bees and flowers and 3. tapeworm and humans 

• Commensalism - good for one, no impact on the other. (+/0) Barnacle and whales, desmodex mites

• Mutualism - both species benefit (+/+) eg. Crocodile and tooth cleaning bird, Clown fishes/anemone, fungus and trees

• Parasitism - good for parasite, bad for the other (host) (+/-) eg: tapeworm, tick, leeches, mosquitoes

define intraspecific

interactions that take place between members of the same species

define top-down control and bottom up control

Top-down control: something from higher in the food chain affects a lower level (predation)

Bottom-up control: something from a lower level affects a higher one

what are the difference of antibiotics and Allopathic agents

• Antibiotics are secreted by microorganisms to kill other microorganisms

• Allopathic Agents secreted by plants into the soil to kill other plants

what does a gas need to contribute to be a greenhouse gas

For a gas to contribute to the greenhouse effect it has to have the following property: it has to absorb longer wavelength radiation. Two other gases, methane and nitrous oxides (NO2 and NO) have that property and contribute.