Biodiversity

Question 1

What is biodiversity?

Answer 1

The variety of life - The range of living organisms to be found. This includes different species as well as variations within a specie.

Question 2

What is is a species?

Answer 2

A group of individual organisms very similar in appearance, anatomy, physiology, biochemistry and genetics; whose members are able to inbreed freely to produce fertile offsprings.

Question 3

What is a habitat?

Answer 3

A place where individuals in a species live. It usually has a specific set of conditions with living organisms living in it usually well adapted.

Question 4

What does biodiversity encapsulate?

Answer 4

1. The variety of different habitats found in a specific location.2. Differences between each species; either anatomically, physiologically…3. Genetic variation between members of the same species.

Question 5

How are samples taken randomly?

Answer 5

1. Samples are taken across the habitat at regular intervals.2. A grid is laid over the habitat and random numbers are generated with a random number generator that are used to obtain random sampling coordinates.3. Alternatively, the grid can be one found on a map. The sampling spot is then found with a GPS.

Question 6

How is sampling size determined?

Answer 6

Sampling size is dependent on the biodiversity of the habitat itself. If the habitat looks diverse, then more samples should be taken to ensure that rarer/ more concentrated colonies of species are included in the sample. If the habitat doesn’t look diverse, less samples will need to be taken. However, when comparing two habitats, the same number of samples should be taken.

Question 7

How are plants sampled?

Answer 7

Plants are usually sampled using quadrats, squares varying in size used for defining the sampling area.

Question 8

What is species richness?

Answer 8

The number of species present in a habitat.

Question 9

What is species evenness?

Answer 9

A measure of the species richness taking into account the number of individuals of that species (population) within a given habitat.

Question 10

How is species richness determined?

Answer 10

Using a quadrat. The number of different species that can be seen within the quadrat are usually counted and noted.

Question 11

What limitations are there with this method?

Answer 11

1. It may be difficult to distinguish between different species if they have similar appearances.2. Smaller, more insignificant plants may be missed.3. Seasonality may affect the number of species that can be seen within the sampling area.

Question 12

How can species evenness be determined?

Answer 12

1. The number of individuals of a species can be counted within a quadrat.2. A visual survey can be done of the quadrat and a measure of abundance can be giving using the ACFOR scale.

Question 13

What are the limitations with this method?

Answer 13

1. Difficult to distinguish between different species and indeed different individuals.2. There may be too many individuals to count.3. Smaller, more insignificant plants are harder to see and therefore their numbers are usually underestimated.

Question 14

What is a better way of estimating species evenness?

Answer 14

Using percentage coverage of different species.

Question 15

How can % coverage be determined?

Answer 15

1. The quadrat can be split into smaller squares, % coverage can be estimated within these smaller squares and totalled at the end.2. A point frame can me used. These are frames with usually a series of 10 needles/ pointers mounted onto them (with the same width as the quadrat). These are moved across the quadrat 10 times and plants touching the pointers are recorded.

Question 16

What are the limitations of using a point frame?

Answer 16

1. Smaller, insignificant plants can be missed.2. More than 1 plant can be touching the pointer with each measurement, giving a % coverage of over 100%.

Question 17

How can species evenness be quantified?

Answer 17

By using Simpson’s diversity index; 1 - [sum(n/N)^2], where n = number of individuals in a particular species and N = total number of individuals in all species. A higher Simpson’s index indicates a greater species evenness.

Question 18

What factors need to be kept the same when comparing different habitats for results to be valid?

Answer 18

1. Number of samples.2. Standard procedure; results should be collected in the same way.3. Other variables; including obvious factors that may affect biodiversity including shade or human factors.

Question 19

What factors may contribute towards different biodiversities?

Answer 19

1. Different light exposure.2. Different consumers present.3. Level of human activity.4. Wind exposure.5. Soil type and quality.6. Disease.7. Availability of water.8. Mineral content of soil.9. pH of soil.

Question 20

What is a transect?

Answer 20

• A line that stretches across a habitat used to determine the biodiversity and change in biodiversity throughout a habitat.
• The line can be a physical rope across the habitat or a line drawn across a map along which samples are taken.
• Samples may be taken at set intervals along the transect. This is called an interrupted belt transect and is used to sample biodiversity quantitatively across a habitat.
• Samples may be taken one after another along the transect. This is called a continuous belt transect and is used to record actual biodiversity quantitatively across the habitat.

Question 21

What are the problems associated with sampling animal diversity?

Answer 21

• Animals are constantly moving. It is therefore difficult to count the exact number of individuals within a habitat exactly.
• Larger animals may detect your presence and will hide away. This will impact the randomness of your sampling.

Question 22

How can problems associated with sampling animal diversity be overcome?

Answer 22

• Use traps to keep a sample of mobile organisms in one place for an extended period of time in order to count their numbers.
• For larger animals, look for signs of their presence, e.g. footprints, droppings…

Question 23

What techniques are used to sample animals?

Answer 23

1. Sweep netting: Walking through a habitat with a stout net and sweeping in wide but regular arcs, then emptying out on a white sheet in order to identify/count the number of individuals. This type of sampling is used in areas of low vegetation or in water.
2. Stick & shake: Using a stick to shake the branches of a tree and using a white sheet to catch whatever falls out.
3. Pitfall trap: Small container buried in the soil, with the rim just below the level of the ground and a small amount of water at the bottom. Any animals crawling past will fall in and be trapped by the water. The trap can be left overnight.
4. Tullgren funnel: A device used to collect organisms that live in leaf litter. The leaf litter is put onto a net and dried by a lightbulb. The organisms that fall out are funnelled into a collection jar.
   Light trap: UV light used to attract flying insects at night. They eventually fall into a collection jar beneath and are prevented from flying away by water or alcohol.

Question 24

How do we measure the species evenness of animals?

Answer 24

Larger animals can be counted, but smaller ones need to be trapped and sampled accordingly:

1. Use a trapping method, e.g. pitfall trap, to trap a sample of animals.
2. Mark members of the same species with something that won’t adversely affect them, e.g. dot of paint, and release whole sample into the habitat again.
3. Take another sample, in the same area and with the same method, after a small time interval.
4. Count the number of members of the same species captured in the second sample as well as the number within that who have been marked.
5. Use the formula Population = (C1C2)/C3 to obtain an estimate for the total population in that area. Where C1 is number of individuals in first sample, C2 is number of individuals in second sample and C3 is marked individuals in the second sample.
6. This information can then be used to estimate population density or other indicators.

Question 25

What is global biodiversity?

Answer 25

The total number of species present on earth at a given time, and the variation between those species.

Question 26

Why can estimates for global diversity be inaccurate?

Answer 26

1. We are unsure we’ve found all species on earth.
2. We are finding new species all the time.
3. Evolution and speciation is an ongoing process.
4. Species are becoming endangered and extinct all the time.