19.3,19.4&19.5: Competition, predation & investigating populations

Question 1

Types of competition

2

Answer 1

Intraspecific

Interspecific

Question 2

Intraspecific competition

Answer 2

Competition between individuals of the same species.

Question 3

The size of a population is determined by…

Answer 3

the availability of resources

Question 4

Interspecific competition

Answer 4

Competition between individuals of different species

Question 5

Competitive exclusion principle

Answer 5

Populations of two different species compete and one has a competitive advantage over the other. One species decreases and one increases and if conditions remain the same, the decreasing population will be fully removed.

Question 6

Predator-prey relationship type of relationship

Answer 6

Interspecific relationship

Question 7

Predation

Answer 7

Occurs when one organism is consumed by another

Question 8

Why does the prey population rarely become extinct in a natural habitat?

Answer 8

There are many places to hide and seek refuge which means that not all prey are caught.

Question 9

Why is it difficult to obtain reliable data in the wild?

Answer 9

Its not possible to count all the individuals so sampling must be used which may not be representative

Question 10

Abundance

Answer 10

The number of individuals of a species in a given space

Question 11

Samples

Answer 11

Samples need to be representative of a habitat as a whole as they are often only small

Question 12

Types of quadrat

2

Answer 12

point quadrat

frame quadrat

Question 13

Point quadrat

Answer 13

Consists of a horizontal bar which is supported by 2 legs and has 10 holes at set intervals along the bar. A long pin is dropped through each and each species that touches the pin is recorded.

Question 14

Frame quadrat

Answer 14

A square frame which is divided by string or wire into equally sized sub divisions, can be folded for transport or storage. Abundance of a species is recorded

Question 15

Factors to consider when using quadrats

3

Answer 15

size of the quadrat
the no. of sample quadrats to record within the study area
the position of each quadrat within the study area

Question 16

Random sampling technique

Answer 16

two tape measures = grid
coordinates
random no. generator

Question 17

When to use systematic sampling

Answer 17

When there is some form of gradual change in communities of plants and animals

Question 18

Belt transect

Answer 18

String or tape across the ground in a straight line

Question 19

Measuring abundance for static species

2 ways

Answer 19

frequency

percentage cover

Question 20

Frequency technique for measuring abundance

Answer 20

Quick idea of species in an area and their distribution which provides numerical information.

Question 21

Frequency

Answer 21

Likelihood of a particular species appearing in a quadrat useful for species like grass

Question 22

Percentage cover

Answer 22

An estimate of the area within a quadrat that a particular plant covers and is useful where a species particularly abundant or difficult to count.

Question 23

Sessile

Answer 23

non-motile/ immobile

doesn’t move

Question 24

Mark-release recapture technique

Answer 24

A no. of animals are caught, marked, recorded and then released. Some time later, a given no. of animals is collected and the number is recorded and the number of marked ones.

Question 25

Mark-release recapture equation

Answer 25

estimated population size:
total no. of individuals in the 1st sample x no. of individuals in 2nd /
no. of marked individuals recaptured

Question 26

Mark-release recapture technique relies on assumptions that…
3

Answer 26

there are few (if any) births and deaths
the mark stays on
method of marking isn’t toxic and doesn’t make individuals more liable to predators