Ecology In The Local Environment

Question 1

What is important do do when sampling

Answer 1

Take a big enough sample for reliable estimate

Sample randomly for a better representation of the population

Question 2

Pooters

Answer 2

Finds out which species are present
You have to be systematic about sampling to get representative results
It is difficult to calculate amount of the species

Question 3

Sweepnets

Answer 3

Difficult to get representative samples particularly in terms of the relative numbers of organisms

Used in long grass or dense woodland with shrubs

Question 4

Pitfall traps

Answer 4

Gives indication of relative number of organisms in a given area if there are enough to give a representative sample

Sometimes ethanol etc is placed at the bottom to kill organisms to stop them escaping

Question 5

Quadrat

Answer 5

Square frames placed randomly to estimate population of a particular species or estimateion can be done by percentage cover

The result in that area is then multiplied for total area giving an estimation

Question 6

Abiotic

Answer 6

Non living factors

Question 7

Biotic

Answer 7

Living factors

Question 8

Describe the capture/recapture method (Lincoln index)

Answer 8

Animals are caught humanely🐭 and their amount is recorded
They are marked and released back into the population
A second sample is taken containing marked and unmarked animals and they are counted
A formula is used to estimate the total population size int he habitat

Question 9

What formula is used to calculate population size (capture/recapture)

Answer 9

Population size= no. In first sample X no. In second sample / no. In second sample previously marked

Question 10

What assumptions are made using the capture/ recapture method

Answer 10

There is no death, immigration or emigration
Each sample is collected the same way without bias
The marks given do not affect their survival rate

Question 11

Compare the biodiversity of natural and artificial ecosystems

Answer 11

Natural ecosystems have many different species and are very biodiverse
Artificial ecosystems have less biodiversity with few species

Question 12

What technique can scientists use to look at how species change between habitats

Answer 12

A line is laid down with regular intervals marked on it
A small quadrat is laid next to the line and the number of different species is recorded
This is repeated as quadrat is moved along at regular intervals until the end of the line

Question 13

What causes zonation and what is it

Answer 13

Gradual change in distribution of species across a habitat

Caused by changes in abiotic factors eg. Trampling near a sea shore or change in temperature

Question 14

Community

Answer 14

Total number of individuals of all the different populations of organisms that live together in a habitat at any one time

Question 15

Biodiversity

Answer 15

Variety of different species living in a habitat

Question 16

Ecosystem

How are ecosystems able to support themselves

Answer 16

Physical environment with a particular set of conditions plus all the organisms that live in it

They can support themselves without any influx of other factors or materials. The energy source (usually sun) is the only external factor

Question 17

What are natural ecosystems

Give example

Answer 17

Not man made (but may be managed or preserved) with good communities of plants and animals

Native woodlands and lakes

Question 18

What are artificial ecosystems

Give example

Answer 18

Man made and carfully comtrolled to keep conditions constant

Eg. Forestry plantations and fish farms🐟

Question 19

Population

Answer 19

Total number of individuals of the same species that lives in a certain area