Succession.

As you should know, ecosystems are dynamic systems (they change), and the process by which they change over time is called succession. 

There are two types of succession: Primary succession and Secondary succession. Primary succession starts on new areas of land with NO organic material or soil (eg. bare rock/sand), for example, new land exposed when sea level drops, or a new surface formed by a volcanic eruption. Secondary succession is when the land has been destroyed or damaged, so succession must start again; the area has been cleared of all plants and must re-develop (eg. plants growing after a forest fire).

The succession occurs in stages called seral stages. The stages for primary succession are: 

1) PIONEER SPECIES COLONISE THE LAND. The abiotic conditions are harsh, there’s no soil to retain water, so these species are specialised to tolerate and survive in these conditions. 

2) PIONEER SPECIES CHANGE ABIOTIC CONDITIONS. As they die, the humus (dead organic material) is decomposed by microorganisms and create a thin, basic soil. 

3) NEW ORGANISMS CAN MOVE IN AND GROW. The soil means more water csn be retained and more nutrients are available for plants. As each organism arrives, dies and is decomposed, more soil is built up and larger plants can live there. Once enough and large enough plants live there, habitats emerge and animals can move in and survive. 

As more species move in and live there, the ecosystem becomes more complex and diversity increases. 
The final seral stage is called the complex community, this is when the ecosystem is at its largest and most complex and won’t change much more; it’s at a steady state. 

Secondary succession occurs the same way, except there is already soil present so succession starts at a later seral stage. 

11 months ago  1 note

Manipulating energy transfer (human activity).

Primary productivity is the energy captured by plants for photosynthesis, just as Secondary productivity is the energy taken in by consumers when they eat another organism. Humans can manipulate energy transfer it when farming to increase the net productivity (and hence increasing the energy that will be transferred to us when we buy the food and eat it). 

FACTORS THAT EFFECT PRIMARY PRODUCTIVITY:

- LIGHT LEVELS; using light banks or planting cops early so they have a longer growing season to harvest light.

- WATER AVAILABILITY; irrigating (creating a water supply for plants by channels) and breeding drought-resistant plants 

- TEMPERATURE; greenhouses provide a warmer temperate and temperature can effect the speed of chemical reactions. 

- NUTRIENTS; a lack of can slow the rate of photosynthesis. Using fertilisers or crop rotation increases the nutrients in soil.

- PEST; pesticides/insecticides can kill pests which remove biomass and energy from the food chain. You can also use natural predators to remove them (releasing ladybugs to eat the aphids). 

- FUNGAL DISEASES; can be defeated by fungicides. fungal infections can rot roots and and damage xylem vessels.

- COMPETITION; from weeds restricts the lights, nutrients and water that the crop can receive. Farmers can combat these with herbicides. 

*

and for secondary the animals of the ecosystem…

*

FACTORS THAT EFFECT SECONDARY CONSUMPTION:

- MOVEMENT; restricting movement means less energy is wasted (although many see this as cruel and worry about animal welfare, preferring free range food), supplying food - and lots of it - means they don’t have to look for it and can store more energy. 

- TEMPERATURE; keeping the organisms warm means less energy is lost through heat. 

- AGE; younger animals invest more energy than adult ones, harvesting just before adulthood helps reduce energy loss.

- ANTIBIOTICS; less energy lost fighting parasites or pathogens. 

- SELECTIVE BREEDING; produce larger breeds with faster growing rates for meat, more resistant breeds, breeds that produce higher quality/higher yield of milk (or meat) etc. 

All these factors effect the productivity of pants and can, when controlled or removed, increase the energy transfer. 

11 months ago 

Succession.

As you should know, ecosystems are dynamic systems (they change), and the process by which they change over time is called succession. 

There are two types of succession: Primary succession and Secondary succession. Primary succession starts on new areas of land with NO organic material or soil (eg. bare rock/sand), for example, new land exposed when sea level drops, or a new surface formed by a volcanic eruption. Secondary succession is when the land has been destroyed or damaged, so succession must start again; the area has been cleared of all plants and must re-develop (eg. plants growing after a forest fire).

The succession occurs in stages called seral stages. The stages for primary succession are: 

1) PIONEER SPECIES COLONISE THE LAND. The abiotic conditions are harsh, there’s no soil to retain water, so these species are specialised to tolerate and survive in these conditions. 

2) PIONEER SPECIES CHANGE ABIOTIC CONDITIONS. As they die, the humus (dead organic material) is decomposed by microorganisms and create a thin, basic soil. 

3) NEW ORGANISMS CAN MOVE IN AND GROW. The soil means more water csn be retained and more nutrients are available for plants. As each organism arrives, dies and is decomposed, more soil is built up and larger plants can live there. Once enough and large enough plants live there, habitats emerge and animals can move in and survive. 

As more species move in and live there, the ecosystem becomes more complex and diversity increases. 
The final seral stage is called the complex community, this is when the ecosystem is at its largest and most complex and won’t change much more; it’s at a steady state. 

Secondary succession occurs the same way, except there is already soil present so succession starts at a later seral stage. 

Manipulating energy transfer (human activity).

Primary productivity is the energy captured by plants for photosynthesis, just as Secondary productivity is the energy taken in by consumers when they eat another organism. Humans can manipulate energy transfer it when farming to increase the net productivity (and hence increasing the energy that will be transferred to us when we buy the food and eat it). 

FACTORS THAT EFFECT PRIMARY PRODUCTIVITY:

- LIGHT LEVELS; using light banks or planting cops early so they have a longer growing season to harvest light.

- WATER AVAILABILITY; irrigating (creating a water supply for plants by channels) and breeding drought-resistant plants 

- TEMPERATURE; greenhouses provide a warmer temperate and temperature can effect the speed of chemical reactions. 

- NUTRIENTS; a lack of can slow the rate of photosynthesis. Using fertilisers or crop rotation increases the nutrients in soil.

- PEST; pesticides/insecticides can kill pests which remove biomass and energy from the food chain. You can also use natural predators to remove them (releasing ladybugs to eat the aphids). 

- FUNGAL DISEASES; can be defeated by fungicides. fungal infections can rot roots and and damage xylem vessels.

- COMPETITION; from weeds restricts the lights, nutrients and water that the crop can receive. Farmers can combat these with herbicides. 

*

and for secondary the animals of the ecosystem…

*

FACTORS THAT EFFECT SECONDARY CONSUMPTION:

- MOVEMENT; restricting movement means less energy is wasted (although many see this as cruel and worry about animal welfare, preferring free range food), supplying food - and lots of it - means they don’t have to look for it and can store more energy. 

- TEMPERATURE; keeping the organisms warm means less energy is lost through heat. 

- AGE; younger animals invest more energy than adult ones, harvesting just before adulthood helps reduce energy loss.

- ANTIBIOTICS; less energy lost fighting parasites or pathogens. 

- SELECTIVE BREEDING; produce larger breeds with faster growing rates for meat, more resistant breeds, breeds that produce higher quality/higher yield of milk (or meat) etc. 

All these factors effect the productivity of pants and can, when controlled or removed, increase the energy transfer. 

Succession.
Manipulating energy transfer (human activity).

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