Ecosystems

Abiotic factor

Non-living factors that can influence where an organism lives

Examples of abiotic factors

Sunlight, water, temperature

Algal bloom

Rapid increase in algae formed at the surface of water which blocks sunlight

Biotic factor

Living factors in an ecosystem that affects other organisms

Examples of biotic factors

Mating partners, parasites, food availability

Decomposers

Organisms that break down dead and waste materials.

Examples of decomposers

Bacteria and fungi

Desalination

Removing salt water from seawater

Eutrophication

Excessive algal and plant growth causes water to become anoxic

Indicator species

Living organisms whose absence or presence reflects a specific environmental condition

Leaching

Soluble mineral ions drain away from soil due to the action of water

Legume

Plant with root nodules containing nitrogen fixing bacteria

Nitrates

Mineral ion in soil responsible for producing amino acids and DNA

Process nitrates are taken by the soil

Active transport

Nitrifying bacteria

Bacteria in oil that converts ammonia into nitrates by nitrification

Nitrogen fixing bacteria

Bacteria in soil and root nodules of legumes, converts nitrogen gas into nitrates

Rate of decay

How fast dead matter is broken down

Calculation of rate of decay

Mass loss / time

Rhizobium bacteria

Nitrogen fixing bacteria found in root nodules or legumes

Non-indigenous species

An organism introduced to an area where it doesn't naturally occur

Respiration

Process converting sugar molecules to release energy

Combustion

Chemical combination of a substance with oxygen

Decomposition

Dead organic matter is broken down into simpler compounds.

Molecules in plants containing carbon

DNA, carbohydrates, lipids and proteins

Consequences when molecules are eaten by animals

Digested into smaller molecules e.g. lipids into fatty acids and glycerol

Molecules egested by animals containing carbon

Urea, CO2, exhaled waste from metabolic procceses

Fossilisation

Preserving organic remains or traces of organisms in rock over long periods.

Process reducing photosynthesis

Deforestation

Process increasing during winter

Combustion

Importance of water to living organisms

Managing blood viscosity, chemical reactions in the cytoplasm

Processes occurring in the water cycle

Percolation, transpiration, condensation, precipitation, run off

The stages of the water cycle

Evaporation, condensation, precipitation, percolation, run off

Solar still

Produces fresh drinking water from sea water

Stages of solar still

Evaporation, Condensation, Run off

Stages of nets to collect water

Wind forces fog through mesh, droplets cling, combine then condense into heavier droplets

Process of water intake into a desalination plant to prevent death of aquatic animals

Seawater is pumped 3x slower than a fish swims

Uses of water

Drinking, sanitation, agriculture

Reverse osmosis

Saltwater passes through a membrane under high pressure, water molecules move oppositely

Disadvantages of desalination

High cost, high-energy use, and large amounts of salty wastewater

Advantages using manure than artificial fertilisers

Manure is insoluble

Why ploughing in the remains is better than burning them

Left over crops decomposes, ammonium ions are converted to nitrates - increases soil fertility

Stage 1 of eutrophication

Run off and leaching of excess nitrates from fertilisers

Stage 2 of eutrophication

Algal bloom

Stage 3 of eutrophication

Plant dies due to lack of sunlight

Stage 4 of eutrophication

Decomposers eat remaining plants

Stage 5 of eutrophication

Organisms die due to lack of oxygen

Stage 6 of eutrophication

Water becomes anoxic

Ways to reduce eutrophication

Using nitrogen-fixing bacteria

Ways that water could be polluted

Chemicals, nitrates

Invertebrates whose presence reflects good water quality

Stonefly larvae and freshwater shrimp

Invertebrates whose presence reflects bad water quality

Bloodworms and sludge worm

Gases that pollute the atmosphere

Carbon dioxide, methane, acidic gases

Lichen

A basic plant that grows on rocks, trees and buildings

Gas that lichen is sensitive to for their growth

Acidic gases

Bacteria that reflect a medium air pollution

Blackspot fungus