Biology - Unit 4 - Succession And Conservation

Front 1

What is succession?

Back 1

This is a process of Ecosystem change over time. Where the abiotic and biotic factors of an ecosystem have changed over time.

Front 2

What are the two types of succession?

Back 2

Primary and Secondary succession.

Front 3

What is primary succession?

Back 3

This occurs on land that is newly formed or exposed, (where sea level has dropped exposing new land). There is no soil or organic material to start with just bare rock.

Front 4

What is secondary succession?

Back 4

Land that has been cleared of all plants, but soil remains (forest fire, or where the forest has been cut down by humans).

Front 5

When does primary succession occur?

Back 5

When a species colonise a new land surface. Seeds and spores are blown in by wind, and begin to grow. The first species to colonise the area are known as the pioneer species, this is the first seral stage.

Front 6

What stages occur after the pioneer species has colonised during primary succession?

Back 6

1 - The abiotic conditions of the environment are hostile, there would be no soil to retain water, so pioneer species population grows, because they are specialised to cope with the harsh conditions.

2 - The abiotic conditions change the abiotic conditions , the die are decomposed and form dead organic matter, forming basic soil.

3 - This basic soil retains water, conditions become even more less hostile, so new organisms move in and grow. (lichens)

4 - These organisms then die, decompose, adding more organic material making the soil deeper and richer in minerals. (moss)

5 - Larger plants and shrubs start to grow in deeper soil, which retains even more water. (grasses, small flowering plants.)

(secondary succession then occurs - same process)

Front 7

What happens during secondary succession?

Back 7

1 - The soil layer (created in primary succession) is already present, so succession starts at a later stage.

2 - At each stage different animals and plants that are better adapted for improved conditions populate.

3 - The new species outcompete the original species, and become the new dominant species.

4 - As succession goes on species diversity increases, and the abundance of each species increases.

5 - The final stage is a climax community being reached, where the ecosystem is at it's largest point. The most complex community has been reached, it will not change much more, it's in a steady state.

Front 8

Why doo different ecosystems have different climax communities?

Back 8

This depends on what a climate is like in the ecosystem. The overall temp of the environment, seasonal weather availability of water etc.

Front 9

When succession is stopped artificially by humans the climax community is called a?

Back 9

Plagioclimax

Front 10

What is an example of humans preventing succession?

Back 10

Mowing a lawn. The longer the intervals between mowing the further into succession the ecosystem can go.

Front 11

What are two other types of preventing succession?

Back 11

Allowing animals to graze in specific areas, managing fires which are lit.

Front 12

What is conservation?

Back 12

Conservation is the protection and management of species and habitats (species).

Front 13

Why is it important to conserve species and habitats?

Back 13

Species are resources for human need. i.e. some rainforests contain plants which provide drugs, clothes and food.

Simply because it is the right thing to do, every organism has the right to exist.

Many species and habitats bring joy to many people.

Conservation can help prevent climate change.

Helps prevent the disruption of food chains.

Front 14

What is an example of a practise that conserves plants?

Back 14

Plants can be conserved by seed banks. A seed bank is a store of lots of seeds from lots of different plants.

Front 15

What is an example of a practise which conserves fish?

Back 15

Fishing quotas, limits tot he amounts of fish fisherman are allowed to catch.

Front 16

What is an example of a practise that conserves animals?

Back 16

Captive Breeding programs.

Front 17

How can an organism be conserved by relocation?

Back 17

This means moving the population of a species to a new location, because they are directly under threat, to a safe and similar environment. It's often used for species which only live in one place and if they die out the species will no longer exist.

This conserves the species as in the new environment they are more likely to survive, and their numbers will increase. Moving can cause problems though such as competition.

Front 18

Give two examples of conservation areas?

Back 18

National parks and Nature reserves.

Front 19

Name two methods that could be used to conserve species from a tropical rainforest.

Back 19

Relocation

Making area a conservation area.

Front 20

What is the difference between primary and secondary succession?

Back 20

Primary succession occurs where there is no living matter bare rock or land no soil is present. Secondary succession begins with a soil base.

Front 21

Name the species that are the first to colonise an area during succession.

Back 21

Pioneer species.

Front 22

What is meant by a climax community.

Back 22

This is the final stage, the ecosystem is at it's largest and most complex.

Front 23

Succession occurs in natural ecosystems. Describe and explain how succession occurs.

Back 23

1. (Colonisation by) pioneer (species);

2. Change in environment/example of change caused by

organisms present;

3. Enables other species to colonise/survive;

4. Change in diversity/biodiversity;

5. Stability increases/less hostile environment;

6. Climax community;

Front 24

Managed ecosystems such as wheat fields are prone to pest infestations. Describe the

advantages and disadvantages of using biological agents to control pests.

Back 24

1. Specific (to one pest);

2. Only needs one application/reproduces;

3. Keeps/maintains low population;

4. Pests do not develop resistance;

5. Does not leave chemical in environment/on crop/no

bioaccumulation;

6. Can be used in organic farming;

Front 25

Changes in ecosystems can lead to speciation. In Southern California 10 000 years ago a

number of interconnecting lakes contained a single species of pupfish.

Increasing temperatures caused evaporation and the formation of separate, smaller lakes

and streams. This led to the formation of a number of different species of pupfish. Explain

how these different species evolved.

Back 25

1. Geographical isolation;

2. Separate gene pools/no interbreeding (between populations);

3. Variation due to mutation;

4. Different environmental/abiotic/biotic conditions/selection

pressures;

5. Selection for different/advantageous, features/characteristics

/mutation//allele;

6. Differential reproductive success/(selected) organisms survive

and reproduce;

7. Leads to change in allele frequency;

8. Occurs over a long period of time;

Front 26

Glaciers are masses of moving ice. When glaciers shrink, the thick covering of ice gradually

disappears to leave behind bare land. Land exposed by a shrinking glacier in Alaska became

covered by dense forest in 150 years.

(a) Explain how succession resulted in the formation of the forest.

Back 26

pioneers/suitable example colonise land;

example of change in environment;

enables change in species;

conditions change further/example to favour trees;

Front 27

Waterlogged soils lack oxygen. Suggest why trees are unable to survive in waterlogged

soils.

Back 27

roots unable to respire (aerobically);

active transport of minerals/other metabolic effect stops;

Front 28

To calculate a diversity index at a given time, it is necessary to know the number of

insects in each population. Name one method that could be used to estimate the total

number of insects in a population.

Back 28

mark, release, recapture;

Front 29

Stage 5 illustrates the final stage of succession which is known as the climax community.

During this stage the number of different species in the habitat and the size of each

population remain fairly constant. Explain what limits the size of populations in a climax

community.

Back 29

1. named nutrient availability;

2. numbers of producers providing energy (for a food chain);

3. light intensity affecting the rate of photosynthesis;

4. disease killing (weaker) members of species;

5. space for nest building / niches;

6. reproductive rate balancing death rate;

7. competition for a named limited resource;

8. (intra and interspecific) competition explained;

9. predation described;

Front 30

Biologists studied the process of succession in an area of wasteland over a period of ten

years. They calculated the index of diversity of the area every year. After three years, the index of

diversity was 1.6. After ten years, it had risen to 4.3.

(a) What information concerning the organisms present in the area is suggested by the

increase in the index of diversity?

Back 30

Increase in number of species;

Increase in numbers of some species;

Front 31

The increase in the index of diversity is one indication that a biological succession is taking

place in the area. Describe those features of a succession that would bring about an

increase in the index of diversity.

Back 31

Initial environment hostile / few organisms adapted;

These organisms change the environment / suitable example;

More niches / more habitats;

Allowing other organisms to become established;

Front 32

What is conservation?

Back 32

Conservation is the protection and management of species and habitats.

Front 33

Why is conservation important?

Back 33

*Species are resources for lots of things that humans need. Like drugs clothes and food. Is not conserved resources would be lost.

*Simply because it is the right thing to do, people believe every organism has the right to exist.

*Many species and habitats bring joy to many people.

*Conserving species and habitats can help prevent climate change, e.g. when trees are burnt down.

*Conserving species and habitats helps to prevent the disruption of food chains.

Front 34

How can plants be conserved?

Back 34

National park and protection agencies, do not allow areas on land to be altered. Also seed banks, where lots of seeds from different plant species are stored. Seeds must be regularly checked to see if the are still viable which is expensive, however if any plant was to go extinct in the wild it could be regrown. And large numbers can also be stored.

Front 35

How can fish species be conserved?

Back 35

Fishing quotas, and limits to the amounts of fish that can be taken out of the ocean. Scientist study fish populations, there are also international agreements. Though many fisherman do not agree with the fishing quotas.

Front 36

How can animals be conserved?

Back 36

Using captive breeding programs. Endangered or extinct species are grown in captivity. e.g. pandas. Animals bred in captivity can be re introduced into the wild. Although this can cause problems like introducing new diseases. Also many believe that captive breeding programs are cruel.

Front 37

What is relocation?

Back 37

Relocation is where a population is moved to a new location where they are not at risk with a similar environment where they are more likely to survive. Although problems could arise for example the species being out competed.

Front 38

How can habitats be conserved?

Back 38

Using protected areas, such as national parks and nature reserves. Although problems include most national parks are tourist destinations so can be harmed by the public.

Front 39

Succession occurs in natural ecosystems. Describe and explain how succession

occurs.

Back 39

1. (Colonisation by) pioneer (species);

2. Change in environment/example of change caused by

organisms present;

3. Enables other species to colonise/survive;

4. Change in diversity/biodiversity;

5. Stability increases/less hostile environment;

6. Climax community;

Front 40

Managed ecosystems such as wheat fields are prone to pest infestations. Describe the

advantages and disadvantages of using biological agents to control pests.

Back 40

Advantages

1. Specific (to one pest);

2. Only needs one application/reproduces;

3. Keeps/maintains low population;

4. Pests do not develop resistance;

5. Does not leave chemical in environment/on crop/no

bioaccumulation;

6. Can be used in organic farming;

Disadvantages

7. Does not get rid of pest completely;

8. May become a pest itself;

9. Slow acting/lag phase/takes time to reduce pest population;

Front 41

Changes in ecosystems can lead to speciation. In Southern California 10 000 years ago a

number of interconnecting lakes contained a single species of pupfish.

Increasing temperatures caused evaporation and the formation of separate, smaller lakes

and streams. This led to the formation of a number of different species of pupfish. Explain

how these different species evolved.

Back 41

1. Geographical isolation;

2. Separate gene pools/no interbreeding (between populations);

3. Variation due to mutation;

4. Different environmental/abiotic/biotic conditions/selection

pressures;

5. Selection for different/advantageous, features/characteristics

/mutation//allele;

6. Differential reproductive success/(selected) organisms survive

and reproduce;

7. Leads to change in allele frequency;

8. Occurs over a long period of time;

Front 42

Glaciers are masses of moving ice. When glaciers shrink, the thick covering of ice gradually

disappears to leave behind bare land. Land exposed by a shrinking glacier in Alaska became

covered by dense forest in 150 years.

Explain how succession resulted in the formation of the forest.

Back 42

pioneers/suitable example colonise land;

example of change in environment;

enables change in species;

conditions change further/example to favour trees;

Front 43

In areas of poor drainage the soil is waterlogged. In these areas the climax community is

bog dominated by the moss, Sphagnum. Explain why bog is described as the climax

community.

Back 43

stable community/no further succession/final community;

Front 44

Waterlogged soils lack oxygen. Suggest why trees are unable to survive in waterlogged

soils.

Back 44

roots unable to respire (aerobically);

active transport of minerals/other metabolic effect stops;