Ecology

Question 1

What is photosynthesis?

Answer 1

Chemical reaction which takes place in leaf
Process in plants in which light energy is trapped by chlorophyll to produce sugars & starch
Endothermic reaction as it must absorb energy to work

Question 2

What are the word & balanced equations for photosynthesis?

Answer 2

Light
Carbon dioxide + water ——-> Glucose + Oxygen
Chlorophyll

                      Light 6CO2 + 6H2O ———> C6H12O6 + 6O2 
                 Chlorophyll

Question 3

Describe the steps of the starch tests & the reason behind doing each step

Answer 3

1. Put the leaf in boiling water; kills leaf, stopping further reactions
2. Boil leaf in alcohol (use water bath, as alcohol flammable); removes chlorophyll from leaf, and makes colour change with iodine easier to see
3. Dip leaf in boiling water again; makes leaf soft & less brittle (alcohol makes leaf rigid)
4. Spread leaf on white tile & add iodine; if starch is present iodine will turn yellow/brown to blue/black

Question 4

How do we make sure the starch test is valid?

Answer 4

Before carrying out investigation, we must destarch plant. This involves leaving plant in darkness for 48 hours. This is necessary to make sure any starch found has been produced during investigation.

Question 5

What are producers?

Answer 5

They can photosynthesise & produce their own food

Question 6

What are primary consumers?

Answer 6

Animals that feed on plants

Question 7

What are secondary consumers?

Answer 7

Animals that eat other animals

Question 8

What are tertiary consumers?

Answer 8

Animals that feed on secondary consumers

Question 9

What is energy flow?

Answer 9

The sequence of trapping sun’s energy and then passing it on to other organisms as they feed

Question 10

What tropic level is a producer?

Answer 10

Level 1

Question 11

What do the arrows represent in food chain?

Answer 11

Direction of the transfer of energy & what eats what

Question 12

What is the source energy for every food chain?

Answer 12

The sun

Question 13

What do plants compete for?

Answer 13

Water
Light
Space
Minerals

Question 14

What do animals compete for?

Answer 14

Water
Food
Territory
Meat

Question 15

How do we demonstrate plants competing against each other?

Answer 15

In general, the more seedlings planted in a pot, the smaller the average mass of each seedling.
This is because the seedlings are competing for light, space, minerals and water

Question 16

What are competitive invasive species? What do they do?

Answer 16

Introduction of new species into areas it isn’t usually found, e.g. grey squirrels from USA to UK
They: out-compete native species, usually causing them harm
Spread rapidly when introduced to region
Are almost always introduced by humans

Question 17

How can we monitor the environment?

Answer 17

Biotic (living) and abiotic (non-living) factors, which are more important for global warming 
Abiotic factors: 
Carbon dioxide levels 
Size of ice fields 
Water levels 
Temperature 
pH 
Biotic: 
Lichens - sensitive plants that can be used to monitor pollution, as they only grow in low pollution areas

Question 18

What is the definition of biodiversity?

Answer 18

The range of species in a particular area

Question 19

Why can fertiliser be bad for the environment?

Answer 19

Fertiliser running into waterways cause green algae to grow to excessive levels. When the algae die, bacteria decompose & break them down & use up most of oxygen in water, killing fish and other animals

Question 20

How be we have better land management?

Answer 20

Reclaim old industrial sites for industry, as this avoids destroying existing habitats to provide land
Use brownfield sites (site of previous housing), for housing, as this prevents having to build on grassland or clearing woodland

Question 21

How can we protect fish stocks?

Answer 21

Introducing fishing quotas
Fishing bans to allow fish to recover
Restriction on net sizes

Question 22

What are nature reserves?

Answer 22

Used to improve biodiversity in region by protecting & conserving rare species & valuable or rare habitats
Can be open to public or closed off depending on how fragile habitat is
They can promote biodiversity by educating public
Usually managed by government agencies or charities