B4

• A physical environment with a particular set of conditions, plus all of the organisms that live in it • Can be artificial or natural

High biodiversity (many different species of plants and animals coexist in the same environment)

They are designed and maintained for a particular purpose so they have a lower biodiversity

They may be used in artificial ecosystems to prevent other animals and plants from growing alongside a crop, which leads to low biodiversity

• Very carefully set up, controlled and monitored • They will have less biodiversity due to the fact they havent been established for as long as natural woodland (takes years to form), and result from the relationships and interactions of the organisms that live there and their surroundings • Fewer species are introduced at the setting up stage and not all species survive from the start

• Have less biodiversity due to the shorter time they have existed compared to lakes • Plus in the absence of many predators, some fish species will thrive, whilst others not • Also there are fewer diseases which may result in too many of certain species reducing others

• The part of the physical environment where an animal or plant lives • The organisms living there will have adapted to their habitat, so may be restricted to living there, may only eat the food there • In a habitat, organisms are distributed at random

The organisms living there will have adapted to their habitat, and may only eat the food there

The total number of individuals of all the different populations of plants and animals that live together in a habitat at any one time

The total number of individuals of the same species that live in a certain area

• Self supporting in all factors (e.g. providing mates, shelter) • Rely on an energy source (the Sun), and producers at the bottom of the food chain

• Pooters • Sweepnets • Pitfall traps • Quadrats

Containers used to collect insects easily, without harming them

Used to collect insects in long grass or moderately dense woodland where there are lots of shrubs

Containers set into the ground that are used to catch small insects, e.g. beetles

Square frames that have sides usually 0.5m long, used to count a smaller, representative part of a population

• Throw them randomly on the ground, then count and record the number of each species within the quadrate • You can then estimate the population of each species in a given area • Quadrat sizes can vary depending on the area studies

• Take a big enough sample to make the results a good estimate; the larger the sample the more accurate the results • Sample randomly; the more random the sample the more likely it is to be representative of the population

• A method used to estimate a population size - Also known as the Lincoln Index

Species move around all the time

1) A trap is used to catch a sample of individuals (e.g. mice) 2) Sample is counted, recorded and each individual is marked with a numbered tag/band or a dot of paint 3) Individuals are released unharmed back into the environment, and given time to redistribute amongst the unmarked population 4) Another sample of individuals is captured, where some are marked and some not 5) The unmarked animals are counted, recorded, marked and released

No. in 1st sample (all marked) x no. in 2nd sample (marked/unmarked) ÷ No. in 2nd sample which were previously marked

• Assume that no organisms have died, immigrated or emigrated between sampling • Make sure that identical sampling methods are used from one visit to the next • Make sure that marking the organisms doesn’t affect their survival (e.g. be careful when using paint on invertebrates because if too much is used it can enter their respiratory passages and kill them)

A larger sample size is more accurate