3.5 Population Size And Ecosyetms

Question 1

Factors affecting population size

Answer 1

-Birth rate
-Death rate
-Immigration
-Emigration

Question 2

Strategies for population growth

Answer 2

-Fugitive species
-Equilibrium species

Question 3

Fugitive species

Answer 3

-Can tolerate competition
-Reproduce rapidly
-Invade new environments
-E.g algae and weeds

Question 4

Equilibrium species

Answer 4

-Competition within a stable habitat
-S shaped curve (one step growth curve)

Question 5

Environmental resistance factors

Answer 5

Abiotic
Biotic

Question 6

Abiotic factors

Answer 6

Temp, pH, light intensity, water availability

Question 7

Biotic factors

Answer 7

Competition for resources (intro and inter), disease, parasites, increase in predator numbers

Question 8

Predator-prey interactions cause both populations to oscillate due to

Answer 8

Negative feedback mechanisms

Question 9

Carrying capacity

Answer 9

Maximum population size of a species that can be sustained by an environment

Question 10

Population crash

Answer 10

Decrease in population number when carrying capacity is exceeded

Question 11

Population growth =

Answer 11

Death + Emigration

Question 12

Density dependent factors which limit population size

Answer 12

Competition
Predation
Disease
Parasitism

Question 13

Density independent factors

Answer 13

Abiotic
Earthquakes
Volcanoes
Wildfire
Extreme weather

Question 14

Abundance

Answer 14

Number of individuals of the same species in a give area

Question 15

Animal abundance can be measured by

Answer 15

Capture-mark-recapture
Kick sampling

Question 16

Sessile abundance can be measured by

Answer 16

-Random sampling (quadrat to find density)
-Systematic sampling (transect to determine change in percentage cover)

Question 17

Quadrats show

Answer 17

Density of an organism in a given area

Question 18

Transects show

Answer 18

Change in percentage cover of species

Question 19

Competitive exclusion principle

Answer 19

-When two species occur in the same habitat, one will outcompete the other
-Two species cannot occupy the same niche

Question 20

Ecosystem

Answer 20

-Community of interdependent species and their habitat
-Made up of biotic and abiotic elements
-Changes over time

Question 21

Producers

Answer 21

-Autotrophic
-Absorb light energy and convert to simple inorganic compounds into more complex organic compounds (carbohydrates)

Question 22

Consumer

Answer 22

-Heterotrophic
-Must ingest or absorb organic carbon from other organisms

Question 23

Detritivores

Answer 23

-Feed on dead organic matter
-Earthworms, woodlice and maggots

Question 24

Decomposers

Answer 24

-Break down organic compounds into simpler inorganic compounds
-These see soluble and can be absorbed by plants
-Bacteria and fungi

Question 25

Why is light not absorbed

Answer 25

-Reflected from leafs surface
-Wrong wavelength