Ecology

Question 1

What is an ecosystem

Answer 1

• A system or area where organisms interact with their physical environment

Question 2

What is population

Answer 2

• The total number of individuals of one species in a particular habitat at a particular time

Question 3

What is a habitat

Answer 3

• area where specific organisms live

Question 4

How to find out population of species in habitat

Answer 4

1- Find area of habitat
2- Generate random coordinates to find out where to place quadrat
3- Measure number of species in one quadrat
4- repeat at least 10x and find an average number
5- Calculate how many quadrats fit into total area
6- Divide this number by the average previously found

Question 5

methods of finding out effects of biotic/abiotic factors

Answer 5

• Random sampling- Quadrat
• Transects

Question 6

What is a community

Answer 6

• The populations of all the species present in an ecosystem at a particular time

Question 7

Ways in which species interact with each other

Answer 7

• Feeding (on each other)
• Competition for resources
• Using abiotic resources

Question 8

What do pyramids of number show

Answer 8

• Show the number of each organism counted in the ecosystem, stacked on top of each other

Question 9

What do pyramids of biomass show

Answer 9

• show to total mass (mass of individual x number of individuals) of organisms in each trophic level
• more accurate than pyramids of number

Question 10

How is energy available at a trophic level expressed

Answer 10

• kilojoules per square metre per year (kJ/ m^2/year)

Question 11

How much of Sun’s energy transferred to producers

Answer 11

• 1-5%

Question 12

Why is light energy from sun to producer the least efficient transfer?

Answer 12

• Some light misses plant or plant’s chroloplast
• some light reflected by cuticle
• some light has wrong wavelength to be absorbed by chlorophyll

Question 13

How much energy is passed down to the next trophic level?

Answer 13

• 10%

Question 14

Why is only small part of energy passed down trophic levels?

Answer 14

• energy lost by
  -movement
  -heat loss
  -egestion of waste
• not all of species consumed e.g bones