Ecosystems Review for A Level Biology

These flashcards cover key concepts related to ecosystems, their dynamics, and human impacts, designed for exam review in A Level Biology.

What is an ecosystem?

A relatively self-contained, interacting community of organisms and the environment in which they live.

What are trophic levels?

The position that an organism occupies in a food web, indicating its role in energy transfer.

What does GPP stand for and what does it represent?

Gross Primary Productivity, representing the total light energy converted to chemical energy by plants per unit area per unit time.

What is NPP?

Net Primary Productivity, which is the energy available to plants after respiratory losses are accounted for (NPP = GPP - R).

What technique is used to assess the abundance of organisms in a habitat?

Methods such as quadrats, transects, ACFOR scales, percentage cover, and individual counts.

What is the significance of decomposers in an ecosystem?

They recycle nutrients by breaking down dead organic matter and waste material, facilitating nutrient cycling.

Define primary succession.

The process of ecosystem development occurring in a newly formed habitat, where pioneering species first colonize the area.

What is secondary succession?

The process of change that occurs in an ecosystem that previously supported life but has been disturbed.

What do pyramids of energy represent?

They depict the flow of energy through trophic levels, showing that energy is lost at each level.

What is the ACFOR scale?

A qualitative measure of abundance where A = Abundant, C = Common, F = Frequent, O = Occasional, R = Rare.

What is the impact of overfishing?

It leads to declining populations of fish species, loss of marine biodiversity, and disruption of aquatic ecosystems.

What roles do the scientific journals and peer review process play in climate change science?

They validate and disseminate research findings, helping to raise awareness and inform policy on climate change.

What is an ecosystem?

A relatively self-contained, interacting community of organisms and the environment in which they live.

What are trophic levels?

The position that an organism occupies in a food web, indicating its role in energy transfer.

What does GPP stand for and what does it represent?

Gross Primary Productivity, representing the total light energy converted to chemical energy by plants per unit area per unit time.

What is NPP?

Net Primary Productivity, which is the energy available to plants after respiratory losses are accounted for (NPP = GPP - R).

What technique is used to assess the abundance of organisms in a habitat?

Methods such as quadrats, transects, ACFOR scales, percentage cover, and individual counts.

What is the significance of decomposers in an ecosystem?

They recycle nutrients by breaking down dead organic matter and waste material, facilitating nutrient cycling.

Define primary succession.

The process of ecosystem development occurring in a newly formed habitat, where pioneering species first colonize the area.

What is secondary succession?

The process of change that occurs in an ecosystem that previously supported life but has been disturbed.

What do pyramids of energy represent?

They depict the flow of energy through trophic levels, showing that energy is lost at each level.

What is the ACFOR scale?

A qualitative measure of abundance where A = Abundant, C = Common, F = Frequent, O = Occasional, R = Rare.

What is the impact of overfishing?

It leads to declining populations of fish species, loss of marine biodiversity, and disruption of aquatic ecosystems.

What roles do the scientific journals and peer review process play in climate change science?

They validate and disseminate research findings, helping to raise awareness and inform policy on climate change.

What is an ecosystem?

A relatively self-contained, interacting community of organisms and the environment in which they live.

What are trophic levels?

The position that an organism occupies in a food web, indicating its role in energy transfer.

What does GPP stand for and what does it represent?

Gross Primary Productivity, representing the total light energy converted to chemical energy by plants per unit area per unit time.

What is NPP?

Net Primary Productivity, which is the energy available to plants after respiratory losses are accounted for (NPP = GPP - R).

What technique is used to assess the abundance of organisms in a habitat?

Methods such as quadrats, transects, ACFOR scales, percentage cover, and individual counts.

What is the significance of decomposers in an ecosystem?

They recycle nutrients by breaking down dead organic matter and waste material, facilitating nutrient cycling.

Define primary succession.

The process of ecosystem development occurring in a newly formed habitat, where pioneering species first colonize the area.

What is secondary succession?

The process of change that occurs in an ecosystem that previously supported life but has been disturbed.

What do pyramids of energy represent?

They depict the flow of energy through trophic levels, showing that energy is lost at each level.

What is the ACFOR scale?

A qualitative measure of abundance where A = Abundant, C = Common, F = Frequent, O = Occasional, R = Rare.

What is the impact of overfishing?

It leads to declining populations of fish species, loss of marine biodiversity, and disruption of aquatic ecosystems.

What roles do the scientific journals and peer review process play in climate change science?

They validate and disseminate research findings, helping to raise awareness and inform policy on climate change.

How do peat bogs provide evidence for climate change?

1. Anaerobic and acidic conditions prevent decomposition of organic matter.
2. Pollen grains are preserved in layers; identifying the species of pollen at different depths reveals the climate at the time that layer was formed.

What is dendrochronology?

The study of tree rings to determine past climates. Wider rings indicate years with higher temperatures and higher rainfall, which were more favorable for growth.

How does global warming affect the life cycles of organisms?

Increased temperatures can lead to accelerated development and altered phenology (timing of seasonal events), such as earlier flowering in plants or earlier migration in birds.

Describe the greenhouse effect.

1. UV and visible light from the sun penetrate the atmosphere and warm the Earth's surface.
2. The Earth re-radiates this as Long-wave infrared radiation.
3. Greenhouse gases (e.g., CO{2}, CH{4}) absorb this infrared radiation, trapping heat in the troposphere.

What is a plagioclimax?

A stable community that arises when human intervention (e.g., grazing, burning, or mowing) prevents natural succession from reaching its climax community.

What is the difference between conservation and preservation?

1. Conservation: Active management of habitats to maintain biodiversity while allowing sustainable human use.
2. Preservation: Protecting habitats by minimizing or banning human interference entirely.