Pack 14 - Ecosystems

Question 1

What do plants compete for?

Answer 1

light water and minerals

Question 2

What do animals compete for?

Answer 2

food territory mates breeding sites

Question 3

What is interspecific competition (plus and example)

Answer 3

Competition between different species (weeds and crops within a field)

Question 4

What is intraspecific competition (plus an example)

Answer 4

Competition within the species (finding a mate)

Question 5

What would happen to predators if prey numbers in an ecosystem declined?

Answer 5

less food results in more intraspecific competition, less reproduction and more mortality

Question 6

What is carrying capacity?

Answer 6

The maximum size that a population can remain sustainable in particular habitat

Question 7

What is an autotroph?

Answer 7

Primary Producers

Question 8

What are heterotrophs?

Answer 8

Primary Consumer
Secondary Consumers
Tertiary Consumer

Question 9

Normally a food chain normally has 4/5 trophic levels but rarely 6 - why is this?

Answer 9

Energy is lost at each trophic level

Not enough energy at the end of the food chain to support further trophic levels

Question 10

How is light energy lost in photosynthesis?

Answer 10

some of the light does not fall on photosynthetic parts of the plant
some of the light is not of an appropriate wavelength
some of the light is reflected/ transmitted through the leaf

Question 11

What is biomass?

Answer 11

mass of organic material in an organism/ecosystem

Question 12

How do you use a calorimeter?

Answer 12

Dry material is burnt in oxygen
Energy given off heats up the water in the calorimeter
Rise in temperature can be used to calculate the energy that was contained in the material

Question 13

What would a stirrer do in calorimeter?

Answer 13

Distributes heat energy evenly around chamber

Question 14

How is production measured?

Answer 14

units of energy per unit of area/volume

Question 15

What is gross primary production (GPP)

Answer 15

Total amount of organic material made in photosynthesis

Question 16

What is net primary production?

Answer 16

Chemical energy store in plant biomass after respiratory losses to the environment have been taken off

NPP=GPP-Respiration

Question 17

How would you calculate the efficiency of energy transfer?

Answer 17

Energy transfer = energy available after the transfer/energy available before the transfer X 100

Question 18

How is energy lost from conusmers?

Answer 18

some food not digested just passed out
excretion
some energy remains within the animal that can’t be eaten

Question 19

What is Net Production of consumers and how can it be calculated?

Answer 19

Production of biomass that is available to other consumers

N = I + (F + R)

N= Net Production
I= Chemical energy stored in ingested food
F= Chemical energy lost to the environment in faeces
R= Respiratory losses to environment

Question 20

How is productivity measured?

Answer 20

amount of biomass made in a given area in a given time

KJm^-2 y^-1

Question 21

What are the main events of Succession?

Answer 21

Hostile environment - colonised by pioneer species
Abiotic environment of habitat changed by pioneer species
The changed environment becomes less hostile to support new species
Establishment of new species increases species diversity as various group of animals enter habitat - pioneer species replaced by new species
Changes in abiotic factors result in less hostile environment (increase in biodiversity)
Climax community develops

Question 22

What is conservation?

Answer 22

the management biological diversity and ecosystem

Question 23

Why does NPP decrease in the later stages of Succession?

Answer 23

Respiration rates increase due to more biomass

Also GPP decreases