Biodiversity

Question 1

What is biodiversity

Answer 1

• the variety among living things within a species, ecosystem or location at a particular time

Question 2

What is an ecosystem

Answer 2

• an environment where a variety of living organsims interact with each other and their physical surroundings

Question 3

What is a biome

Answer 3

• a large geographic region characterised by a certain climate and certain organism living there –> influenced by abiotic factors
• can contain several ecosystems
• marine/desert/forest/grassland/freshwater/tundra

Question 4

Measuring Biodiversity

Species Richness

Answer 4

• the number of species counted in the sampling process using a quadrat

Question 5

Pros and Cons of Species Richness

Answer 5

Strengths:
* provides an idea of how many species inhabit an ecosystem
* large number of species –> greater biodiversity

Limitations:
* no indication of how plentiful each species is
* no indication of the evenness of distribution

Question 6

Measuring Biodiversity

Relative Species Abundance

Answer 6

• the number of each species counted in proportion to other species sampled

Question 7

Pros and Cons of Relative Species Abundance

Answer 7

Strengths:
* shows if one species is more plentiful - dominant - than others

Limitations:
* does not take into account the size of the species involved
* gives no indication of the evenness of distribution

Question 8

Measuring Biodiversity

Percentage Cover

Answer 8

• an estimate of percentage of each quadrat that a species occupies
• good for species that are of very different sizes

Question 9

Measuring Biodiversity

Percentage Frequency

Answer 9

• the percentage of quadrats in which a species is counted
• indicates the evenness of species distributions as well as abundance

Question 10

Sampling using a quadrat

Answer 10

Lack of Bias
* samples taken randomly –> use transect
* Law of Large numbers

On a large scale:
* use an aerial/drone photograph as your transect
* limitation –> smaller species will be missed

Question 11

Measuring Biodiversity

Simpson’s Diversity Index (SDI)

Answer 11

• measures biodiversity of an ecosystem based on data collected from a quadrat
• values range from 0 (not diverse) to 1 (infinite diversity)

Question 12

Species Diversity across time in ecosystems

Temporal variation in diversity over a day

Answer 12

• some animals are nocturnal /dirunal
• in an intertidal ecosystem –> diversity varies with tide
• some birds are migratory and only appear within an ecosystem at a specific time of the year
• in temperate regions, animals hibernate during winter

Question 13

Abiotic Factors

Answer 13

• non living parts of an ecosystem that help shape its enviornment
• temp/rainfall/pH/soil moisture
• in smaller ecosystems –> less variation in abiotic factors
• with vertical space –> signficant variation in abiotic factors

Question 14

How environmental factors limit the distribution/abundance of species

What are the limiting factors that affect distribution

Answer 14

tolerance limits limit the distribution of a species:
* the range of values for a particular condition within which a species can survive
* these are commonly abiotic factors

factors affecting abundance:
* predators
* shortage of food
* shelter
* lack of nutrients in water
- they all ensure a species’ population is restricted in size