Biodiversity

Question 1

Def of “species richness.”

Answer 1

• Species richness is a measure of the number of different species in
  a community.

Question 2

What can biodiversity be used to describe?

Answer 2

• Can describe a range of habitats; from small, local habitat to the whole earth.

Question 3

Is low biodiversity always a concern? If not, why? And when WOULD it be concerning?

Answer 3

• No.
• Expected in areas that have harsh abiotic factors/ if population is very small. ie. the arctic.
• Would be concerning if there was A DECREASE in biodiversity; caused by human activities.

Question 4

What 3 different farming techniques will reduce biodiversity? What must be done to solve this issue?

Answer 4

• Destroying hedgerows
• Selective breeding
• Monocultures
• To solve: compromises need to be made between conservation (of biodiversity) and farming.

Question 5

What is “index of diversity?”

Answer 5

• An index of diversity describes the relationship between the number of species in a community and the number of individuals in each species.

Question 6

Formula to calculate index of diversity:
d =N (N − 1) / Σn( n − 1)
What do the different aspects of this formula stand for?

DON’T NEED TO REMEMBER THIS FORMULA, WILL BE GIVEN. BUT, NEED TO REMEMBER WHAT DIFFERENT ASPECTS OF FORMULA MEAN!!

Answer 6

• N: total no of organisms OF ALL SPECIES.
• n: total no of organisms of EACH SPECIES.
• Σ = sum of

Question 7

How can genetic diversity within OR between species be determined?

Answer 7

Compare:
- * the frequency of measurable or observable characteristics.
* the base sequence of DNA
* the base sequence of mRNA
* the amino acid sequence of the proteins encoded by DNA
and mRNA.

Question 8

True or False

Genetic diversity refers to all the different alleles you find in one species only.

Answer 8

• False.
• Genetic diversity CAN refer to different alleles you find in one species BUT can also refer to different alleles/ genes found BETWEEN species.

Question 9

What do quantitative investigations of VARIATION within a species involve?

Answer 9

• Collect data from random samples.
• Calculating mean value of collected data and standard deviation of mean.
• Interpret the mean values and their standard deviations (ie. seeing if the standar deviations overlap.)

Question 10

How has gene technology caused a change in methods of calculating genetic diversity?

Answer 10

• Inferring DNA differences from measurable/ observable characteristics has been replaced by direct investigation of DNA sequences.

Question 12

Exam Q

Describe how you would investigate the effect of an invasion by a non-native species of
plant (a biotic environmental factor) over many years on the abundance of a native species
of plant in a community.

Answer 12

• Place large no of quadrats (selected at random.)
• Count no of native plants in quadrats.
• Repeat at same time of year every year.

Question 13

How can you calculate a MORE accurate value for index of diversity?

Answer 13

• Take more samples/ find mean.
• Select samples randomly ie. random co-ordinates.

Question 14

2024 AS

A student wanted to determine the mean height of plant species growing in a field.
Describe how student should obtain measurments of plants and process these measurements to obtain a reliable mean heaight of plants growing in the field.

Answer 14

• Divide area into squares.
• Use random computer to generate random co-ordinates.
• For each plant, measure from ground to the highest leaf.
• Measure large no of plants.
• Sum of heights/ no of plants.
• Calculate running mean until no becomes constant.