3.4.7 investigating biodiversity

Question 1

what is genetic diversity?

Answer 1

use genetic diversity to compare within or between species

can use DNA base sequences, mRNA base sequences, amino acid sequences and immunology to compare and classify species

Question 2

classification using DNA/mRN sequences

Answer 2

comparing the DNA and proteins of different species to understand their evolutionary relationships

species which are more closely related will have similiar DNA sequences

Question 3

describe DNA hybridisation

Answer 3

comparing DNA of two species

1. DNA from two species is extracted, purified and cut into short pieces
2. DNA is heated to separate the strands and break hydrogen bonds
3. DNA from one species is joined to a complimentary strand from another species
4. new hybrid strands are formed containing one strand from each species
5. the more closely related the two species are the greater number of hydrogen bonds and complimentary base pairs
6. higher temperatures needed to split strands, the more closely related the species are

Question 4

how is biodiversity classified using proteins?

Answer 4

amino acid sequences in specific proteins can be used to investigate relationships between organisms

sequences are determined by mRNA, which is complimentary to DNA

genetic diversity within and between species can be studied by examining the sequences of amino acids

Question 5

how is biodiversity classified using immunology?

Answer 5

when a pathogen causes an infection, WBC produce antibodies against the antigens

antibodies bind to antigens and cause molecules to agglutinate (stick together)

produces a precipitate and the more similar two species are, more precipitate is formed

Question 6

immunological comparison of proteins

Answer 6

humans are most similar to chimpanzee

more precipitate = greater number of similarities in antigens

Question 7

how is biodiversity compared using observable characteristics?

Answer 7

has its limitations because a large number of characteristics are coded by the same gene. POLYGENIC

characteristics can also be modified by the environment.

Question 8

what is interspecific and intraspecific variation?

Answer 8

interspecific variation = if one species differs from another

intraspecific variation = members of the same species differ from each other

Question 9

why may individuals not be included due to measurements from random sampling?

Answer 9

sampling bias = selection process may be biased. Investigator may be making unrepresentative choices

chance = individuals may be chosen by pure chance and may not be representative

Question 10

describe a method of random sampling

Answer 10

1. divide the study area into a grid of numbered lines
2. using random numbers, from a table or generated by a computer to obtain a series of coordinates
3. take samples at the intersection of each pair of coordinates

Question 11

how can we remove chance from a random sampling process?

Answer 11

• use a large sample size = more individuals that are selected, the small the probability that chance will influence the results
• analysis of data collected = data can be analysed using statistical tests to determine the extent to which chance influenced the data

Question 12

what is a normal distribution curve?

Answer 12

bell shaped and typically shows continuous variation

graph is symmetrical around a central value