Unit 3, Topic 2: Ecosystem Dynamics

Question 1

describe transfer and transformation of matter as it cycles through ecosystems (water cycle) by drawing a diagram

Answer 1

Precipitation -> Collection (run off) -> Evaporation -> Condensation

Question 2

describe transfer and transformation of matter as it cycles through ecosystems (carbon cycle) by drawing a diagram

Answer 2

plants absorb C in photosynthesis (turn into chemical energy) -> animals consume plant and C -> released during cellular respiration -> decomposers breakdown dead organism and return C to atmosphere -> or they remain in the ground and become fossil fuels which then are burned by humans (combustion) releasing C

Question 3

describe transfer and transformation of matter as it cycles through ecosystems (nitrogen cycle) by drawing a diagram

Answer 3

Nitrogen fixed into soil through nitrogen-fixing bacteria and the N2 is converted into ammonium (ammonification) -> ammonia to nitrite (nitrification) when nitrifying bacteria creates nitrate (plants absorb) (assimilation) -> animals then absorb from consuming plants (assimilation) OR denitrifying bacteria release N back into atmosphere as N2 (denitrification) -> plants die and decomposers perform ammonification.

Question 4

define ecological niche in terms of habitat, feeding relationships and interactions with other species.

Answer 4

the role and space than an organism fills in an ecosystem, including all its interactions with the biotic and abiotic factors of its environment

Question 5

what is the competitive exclusion principle?

Answer 5

it states that no two species can occupy exactly the same niche in an ecosystem

Question 6

define keystone species (1 definition, 2 characteristics)

Answer 6

• a plant or animal that plays a unique and crucial role in the way an ecoystem functions.
• maintains carrying capacity by regulating pop.
• regulates populations of speceis to ensure biodiversity

Question 7

define the term carrying capacity

Answer 7

the maximum number of organsims an ecosystem can support based on the availability of resources and services

Question 8

Explain ecological succession

Answer 8

the progressive change of communities overtime in response to changes in their environment.

Question 9

Explain ecological succession

Answer 9

the progressive change of communities overtime in response to changes in the environment.

Question 10

Identify features of a pioneer species that make them effective colonisers (4)

Answer 10

ability to fixate nitrogen, tolerance in extreme conditions, rapid germination (growth from seedling), ability to photosynthesise