B4a-ecology In The Local Environment

Question 1

What is a population?

Answer 1

All the organisms of one species in a habitat

Question 2

What are two ways to estimate population size?

Answer 2

• scaling up from a small sample area

- capture recapture method

Question 3

Describe a method to estimate population size by scaling up from a small sample area?

Answer 3

1) count all organisms in a 1m2 quadrat

2) multiply the number of organisms by the total area of the habitat

Question 4

What is the effect of sample size on the accuracy of an estimate of population size?

Answer 4

The bigger the sample size, the more accurate your estimate of the total population is likely to be

Question 5

Describe the capture recapture method

Answer 5

1) capture a sample of population and mark the animals
2) release them back into the environment
3) recapture another sample of the population
4) count how many are marked
5) use equation

Question 6

What are the assumptions when using the capture recapture method?

Answer 6

• no death, immigration or emigration
• identical sampling methods
• marking not affecting survival rate

Question 7

What is an ecosystem?

Answer 7

All the organisms living in a particular area, as well as all the non living conditions

Question 8

What is a habitat?

Answer 8

The place where an organisms lives

Question 9

What is a community?

Answer 9

Populations of different species in habitat

Question 10

How are ecosystems self supporting?

Answer 10

They contain everything they need to maintain themselves. Water, nutrients and essential elements

Question 11

Describe how to map the distribution of organisms in a habitat using a transect line

Answer 11

• mark out a line using a tape measure
• place quadrats next to each other all the way along the line
• count and record the organisms you find in the quadrats

Question 12

What is zonation?

Answer 12

Zonation is the gradual change in the distribution of species across a habitat

Question 13

How can a gradual change of an abiotic factor result in the zonation of organisms in a habitat?

Answer 13

Example:

In a coastal habitat, changes in salinity and soul depth result in zones where different types of plants grow

Question 14

What are abiotic factors?

Answer 14

Non living, physical factors in an environment

Eg light, temperature, water, oxygen, salinity and soil quality

Question 15

What is biodiversity?

Answer 15

A measure of the variety of life in an area

Question 16

Why do natural ecosystems have a higher biodiversity than artificial ones?

Answer 16

• Natural ecosystems maintain themselves without any major interference from humans eg native woodlands
• artificial ecosystems are created and maintained by humans eg fish farms

Question 17

What are the differences between native woodlands and forestry plantations?

Answer 17

Native woodlands:

• variety of tree species
• trees different sizes and ages
• variety of plant species
• variety of habitats
• variety of animal species

Forestry plantations:

• one species of tree
• trees planted at the same time/same age
• fewer plant species
• fewer habitats
• fewer animal species

Question 18

Why are there fewer plant species in a forestry plantations?

Answer 18

Trees densely packed, leaving less room and light for other plants

Question 19

Why are there fewer habitats in a forestry plantation?

Answer 19

There arent enough plant species to create them

Habitats are disturbed or destroyed when trees are felled

Question 20

Why are there fewer animal species in a forestry plantation?

Answer 20

There aren’t as many habitats or sources of food

Question 21

What are the differences between lakes and fish farms?

Answer 21

Lakes:

• many different fish species
• variety of plant species
• variety pf animal species

Fish farms:

• one fish species
• fewer plants species
• fewer animals species

Question 22

Why is there one fish species in fish farms?

Answer 22

They are farmed for food

Question 23

Why are there fewer plant species in fish farms?

Answer 23

Fish food is added and food waste can cause algal blooms.

Algal blooms block out the light, killing plants

Question 24

Why are there fewer animal species in fish farms?

Answer 24

Predators are kept out
Pests are killed
Less food and fewer habitats because of lack of plants