BY5.7 - Energy and Ecosystems

Question 0

What is an ecosystem?

Answer 0

All the /biotic/ and /abiotic/ /factors/ in an area

Question 1

What is a habitat?

Answer 1

The /environment/ where an /organism/ normally /lives/

Question 2

What is a community?

Answer 2

The /different populations/ of /species/ living in a /particular habitat/

Question 3

What is a population?

Answer 3

A /group of organisms/ of the /same species living/ in a /particular area/ that can /interbreed/

Question 4

what is usually the source of energy in all ecosystems?

Answer 4

sunlight

Question 5

What is photosynthesis?

Answer 5

The /route/ by which /light energy is converted into /chemical energy/ - e.g. /organic compounds - glucose/ and is /made available to organisms within an ecosystem/

Question 6

What are (primary) producers?

Answer 6

Organisms that convert light energy into chemical energy base of every food chain found within every ecosystem

Question 7

Why is not all the light energy that reaches the leaf converted into chemical energy?

Answer 7

1) light reflected by leaf surface 2) light not absorbed (chlorophyll only absorbs red + blue wavelengths) 3) light is transmitted through the leaf (without hitting chlorophyll) 4) photolysis - light is absorbed by water

Question 8

What is photosynthetic efficiency?

Answer 8

A measure of how well a plant is able to capture light energy Energy converted into photosynthesis products P.E = ——————————————————– total light energy falling on plant

Question 9

What is gross primary productivity?

Answer 9

The total amount/rate of which organic compounds are produced by photosynthesis.

Question 10

What is net primary productivity?

Answer 10

The produce that is left after some of the GPP has been used by the plant in respiration NPP = GPP - Energy used by the plant in respiration

Question 11

What does Net Primary Productivity represent?

Answer 11

food available to consumers

Question 12

What is succession?

Answer 12

The change in structure and composition of communities over time

Question 13

What is primary succession?

Answer 13

Start: Bare rock/sand - e.g. volcanic eruption/retreating glacier

Question 14

What is Secondary succession?

Answer 14

STARTS WITH SOIL -FEW/ NO SPECIES e.g FOREST CLEARING following FOREST FIRE

Question 15

How does the starting harsh abiotic environment become habitable through succession?

Answer 15

1) bare rock colonised by PIONEER SPECIES - LICHEN/BACTERIA 2) PIONEERS erode rock - form thin soil 3) ORGANIC MATTER accumulates from DEAD LICHENS/BACTERIA 4) community replaced by MOSSES/FERNS 5) replaced by GRASSES 6) MORE HABITATS available - SMALL ANIMALS join community 7) BIODIVERSITY INCREASES 8) SHRUBS AND BUSH community arrives 9) CLIMATE COMMUNITY - WOODLAND

Question 16

What human activities can prevent the climax community from being established?

Answer 16

1) Sheep grazing 2) quarrying/ mining 3) deforestation - soil erosion

Question 17

what happens as the climax community is approached?

Answer 17

1) increase in SPECIES DIVERSITY –> more niches 2) increase in GPP/NPP –> Increase in PLANT BIOMASS 3) more species = more COMPLEX FOOD WEBS = Habitat becomes MORE STABLE (more to feed on) 4) Biotic factors have more of an effect on determining species present e.g. competition/predatation/disease