B7: ECOSYSTEM + BIOTIC AND ABIOTIC FACTORS

Question 1

What is an ecosystem?

Answer 1

the interaction of a community of living/biotic organisms with the non-living/abiotic parts of their environment (eg: marine, woodland, pond)

Question 2

What are some abiotic factors?

Answer 2

-moisture level/humidity (affects rate of transpiration)
-light intensity (limiting factor of photosynthesis)
-temp (limiting factor of photosynthesis)
-CO2 conc (limiting factor of photosynthesis)
-wind intensity/direction (affects reproduction by seed dispersal)
-O2 levels (aquatic) (affects aerobic respiration)
-soil pH and mineral content (affects amount of chlorophyll (Mg) and protein synthesis (nitrate ions))

Question 3

Explain the effect on population size of plants due to a decrease in light intensity/temp/CO2 conc

Answer 3

-decrease in photosynthesis due to decrease light intensity/temp/CO2 conc
-affects plant growth and success in competing for resources
-decrease in population size

Question 4

What is eutrophication?

Answer 4

the process in which a water body becomes overly enriched with nutrients, leading to an increase in the population of plants

Question 5

Explain the process and effects of eutrophication on the population of organisms in a pond

Answer 5

-excessive nutrients (nitrates) from fertilisers are flushed from the land into rivers by rainwater
-these nutrients cause increased aquatic plant growth of algae and other plants
-algae blooms prevent sunlight reaching other plants
-the plants begin to die.
-dead plants are decomposed by bacteria, which use up the O2 in the water during respiration
-O2 levels reach such a low point that fish and other organisms suffocate

Question 6

What are some biotic factors?

Answer 6

-new predators
-new pathogens
-competition
-availability of food

Question 7

What are the different levels of organisation in an ecosystem?

Answer 7

-individual
-population (group of same species)
-community (groups of different species (biotic factors))
-ecosystem (biotic and abiotic factors)

Question 8

What do animals compete for?

Answer 8

-food
-mates
-territory

Question 9

How are animals adapted to be able to compete successfully?

Answer 9

-camouflage
-muscle (strength and speed)
-structural features (claws/teeth)

Question 10

What do plants compete for?

Answer 10

-light
-water
-mineral ions
-space

Question 11

How are plants adapted to be able to compete successfully?

Answer 11

-large leaves packed with chlorophyll
-extensive root system
-height

Question 12

What do species depend on other species for?

Answer 12

-food
-shelter
-pollination
-seed dispersal

Question 13

What is a stable community?

Answer 13

all species and environmental factors are in balance so that population sizes remain fairly constant