Ecology

Question 1

Describe the factors of a ecosystem

Answer 1

Biotic:
Producers - organisms that make their own food
Consumers - organisms that eat other living things
Decomposes - organisms which decay dead organic matter to obtain their food, help recycle nutrients
Abiotic:
Physical Environment- all the abiotic factors which affect growth and survival of living things, like temp, CO2, O2, minerals, conc…

Question 2

How would you investigate the size of an organism using quadrats?

Answer 2

Using a quadrat (count top and left edges only).

1. Calc area
2. Measure no of individuals in quadrat and repeat
3. Calc average no of individuals in a quadrat
4. Calc how many quadrats fit into total area
5. Multiply result from step 4 by result from step 3

Question 3

What is random sampling?

Answer 3

Make sure data is valid by avoiding bias areas
To take a random sample:
1. Lay out 2 tape measure to make right angle, generate random coordinates (0-10)
2. Use coordinates to place quadrats
To Measure population:
1. Place on ground
2. Count no of individuals in square

Question 4

How to investigate the distribution of organisms and measure biodiversity using quadrats?

Answer 4

1. Pick 2 contrasting areas and set up grid, use random sampling with quadrat and compare average
2. Use transect (line across habitat, placed to pass through abiotic and biotic conditions). Quadrat placed at random points along transect and used to measure % cover of species

Question 5

How can factors affect population size and distribution?

Answer 5

Habitats are not uniform and there will be differences in abiotic conditions like light intensity or one area may be trampled.

Question 6

What are the names given to different trophic levels?

Answer 6

Producers, primary, secondary and tertiary consumers, decomposers

Question 7

What is a food chain?

Answer 7

Show feeding relationships in an ecosystem (simple). Arrow means eaten by, show direction energy moves.

Question 8

What are food webs?

Answer 8

More complex to show links between many species, useful for understanding links between species in a community.

Question 9

What is a pyramid of number?

Answer 9

Show no of each organism counted in ecosystem, odd shaped due to different masses

Question 10

What is a pyramid of biomass?

Answer 10

Show total mass of organisms in each trophic level (mass of individual x no of individual)
Accurate way of looking at relative amount of organisms.

Question 11

What is an ecological pyramid?

Answer 11

Represent the relative amounts of organisms at each trophic level, always drawn to scale