Population growth

Question 1

Define a population

Answer 1

An interbreeding group of organisms of the same species occupying a particular habitat

Question 2

why are ecosystems considered dynamic

Answer 2

1) The intensity of energy flowing through them varies
2) Biological cycles vary mineral availability
3) Habitats change as succession occurs
4) New species arrive and some species are no longer present

Question 3

How is an increase in size of the populations determined

Answer 3

Immigrations+Birth rates is greater than emmigration+death rate

Question 4

Define Birth and Death rate

Answer 4

Birth= the number of births per 1000 individuals per unit of time
Death= the number of mortalities per 1000 individuals per unit of time

Question 5

Describe the difference between fugitive species and equilibrium species

Answer 5

Fugitive species are species that are poor at competition, instead, they rely on a large capacity of reproduction and dispersal for increases in population
COMPARED TO
Equilibrium species who control their populations by competition rather than dispersal and reproduction

Question 6

Draw the one-step growth curve

Question 7

Describe the Lag phase

Answer 7

1) There is a very slow increase in populations due to a period of adaptations to the environment, enzyme synthesis, protein synthesis and time to reach sexual maturity

Question 8

Describe the exponential growth phase

Answer 8

The number of immigrations+ birth rates is higher than death and immigration rates
There is no environmental resistance

Question 9

Describe the stationary phase

Answer 9

Occurs when birth rates are equal to death rates
the population has reached its carrying capacity
environmental resistance begins to increase, limiting growth of population

Question 10

Define carrying capacity

Answer 10

The maximum number of individuals an ecosystem can sustainably supply, over which the population fluctuates around

Question 11

Define density dependant and density independent factors

Answer 11

1) Factors that increase as the population density increases

2) the effect of these factors does not depend on the population density

Question 12

List some density dependant factors that regulate population increase

Answer 12

food availability 
Nesting sites 
shelter
disease/ parasites
predation

Question 13

List some density independent factors that regulate population increases

Answer 13

Soil PH
Light
Temperature
Extreme weather events eg flooding

Question 14

How is the abundance of species measured

Answer 14

1) capture-mark-recapture methods

2) Use of quadrats

Question 15

Describe the method of assessing the abundance of species

Answer 15

1) Place two 10 metre measuring tapes at a right angle to each other, creating a grid
2) using a random number table, trace down one column to the first two numbers
3) using the grid and the coordinates place the quadrat
4) count and identify the number of species in the quadrant
5) estimate percentage frequency

Question 16

Describe the method of finding the distribution of species

Answer 16

1) Measure out 10m in the interested area
2) Every metre place a quadrant
3) Identify the percentage cover of t, the species being identified, in the quadrant
4) continue all the way along the 10m
5) Plot data as a kite diagram to provide easy analysis