Ecology and energy transfers (5.1-5.4, 5.10-5.11, 5.21)

Question 1

Ecosystem

Answer 1

All the organisms and abiotic factors living in a particular area

Question 2

Habitat

Answer 2

The place where an organism lives

Question 3

Population

Answer 3

All the organisms of one species in a habitat

Question 4

Population size

Answer 4

The number of individuals of one species living in a particular area

Question 5

Community

Answer 5

All the organisms of different species living in the same habitat which interact with each other

Question 6

Abiotic factors

Answer 6

Non living features of an ecosystem

Question 7

Biotic factors

Answer 7

Living features of a ecosystem

Question 8

How does temperature as an abiotic factor increase population size

Answer 8

If temp is ideal for the mammal then they don’t need to use up energy in metabolic reactions to maintain their body temp, and can instead use it for growth and reproduction

Question 9

How can temperature as an abiotic factor decrease population size

Answer 9

If temp is lower or higher than optimum body temp then the mammal has to use lots of energy to maintain the correct body temperature. Less energy can be used for reproduction and growth, so population size will decrease

Question 10

Interspecific competition

Answer 10

Where organisms of different species compete for same resources

Question 11

Intraspecific competition

Answer 11

When organisms of the same species compete for the same resources

Question 12

Carrying capacity

Answer 12

The maximum stable population size of a species an ecosystem can support

Question 13

Distribution because of abiotic factors

Answer 13

Where non living factors affect where an organism is situated
Eg. Some plants only grow on south facing slopes in the Northern hemisphere because light intensity is the greatest

Question 14

Distribution because of biotic factors

Answer 14

In interspecific competition there is a species that is likely to be outcompeted and wont be able to survive alongside the other species

Question 15

Niche

Answer 15

The role/position of a species in an ecosystem

Question 16

How niche accounts for abundance of species

Answer 16

Two species occupying similar niches will compete, so fewer individuals of each species will be able to survive in that area

Question 17

How niche accounts for distribution of species

Answer 17

Organisms can only survive in a habitat where all conditions that make up their role exist

Question 18

Abundance

Answer 18

The relative representation of a species in an ecosystem

Question 19

Succession

Answer 19

The process of an ecosystem changing over time

Question 20

Where does primary succession occur

Answer 20

On newly formed or exposed land

Eg. Bare rock

Question 21

Where does secondary succession occur

Answer 21

Land that’s cleared of all plants so only soil remains

Question 22

Process of succession

Answer 22

• Primary succession occurs where a pioneer species arrives
• Pioneers change the abiotic conditions by breaking up rock and forming soil which is suitable for other species like moss
• The moss dies and decomposes, making ti more suitable for shallow plants to grow
• Secondary succession then occurs
• Larger plants outcompete the existing community as they are better adapted and become the dominant species
• Ecosystem become more complex, with biodiversity increasing
• Climax community is reached

Question 23

Pioneer species

Answer 23

The first organisms to colonise the newly exposed land which can withstand the harsh environment

Question 24

Climax community

Answer 24

The final stage of succession where the conditions are stable

Question 25

Climax community

Answer 25

The final stage of succession where the conditions are stable

Question 26

Productivity

Answer 26

The rate of generation of biomass in an ecosystem

Question 27

Primary productivity

Answer 27

The rate at which biomass is stored within autotrophs as organic chemicals

Question 28

Biomass

Answer 28

The mass of living material in an organisms, indicating how much energy an organisms contains

Question 29

Gross primary productivity

Answer 29

The total biomass/energy fixed by photosynthesis per unit area per unit time

Question 30

Percentage of light energy going from sun to Gross Primary Productivity (Energy stored in autotrophs)

Answer 30

1%

Question 31

Why is energy efficiency poor from the sun to GPP

Answer 31

Not all light falls on producers
Light is reflected
Light misses chloroplasts
Some of the light is the wrong wavelength and not absorbed by chrlophyll

Question 32

Why is not all GPP available to herbivores

Answer 32

Lost in the food chain through processes like respiration

Question 33

Net Primary Productivity

Answer 33

The proportion of GPP which can be passed onto the next trophic level

Question 34

NPP calculation

Answer 34

NPP = GPP - Respiration

Question 35

Reasons why biomass is lost between the 1st and 2nd trophic levels

Answer 35

Plant material enters detritus
Plant material is not available to be eaten
Plant is doing metabolic reactions
Plant is reproducing

Question 36

Calculation for efficiency of biomass transfer

Answer 36

Biomass at higher transfer
————————————– = Efficiency of energy transfer
Biomass at lower transfer

Question 37

Carbon cycle

Answer 37

The movement of carbon between organisms and atmosphere