Chapter 10 - Biodiversity

Question 1

What is the definition of a species?

Answer 1

If 2 organisms can interbreed and produce living, fertile offspring

Question 2

What is the binomial system?

Answer 2

Organisms are identified by two names = ‘bi’ meaning 2

• made for a universal system
• first name = generic name and denotes the genus to which the organism belongs to
• second name = species name and denotes the species to which the organisms belongs

Question 3

What are the rules applied to the binomial system?

Answer 3

1. When handwritten, names must be underlined to show they are scientific
2. Generic name first letter is upper case but species name is lower case
3. If species name is unknown - written as ‘sp.’

Question 4

What is courtship behaviour in organisms and why is it important?

Answer 4

A necessary precursor to attracting + successfully mating

• recognise members of their own species - ensure mating only takes place in same species
• identify a mate that is capable of breeding - both partners need to be sexually mature, fertile + receptive to mating
• form a pair bond = successful mating and raising of offspring
• synchronise maturing - only takes place when max probability of sperm and egg meeting
• become able to breed - by bringing a member of opposite sex into physiologically state that allows breeding

Question 5

What is phylogenetic classification?

Answer 5

Based upon the evolutionary relationships between organisms and their ancestors

• classifies species into groups using shared features derived from their ancestors
• arranges the groups into a hierarchy - in which smaller groups are contained within larger groups with no overlap

Question 6

What is each group called within a hierarchy?

Answer 6

A taxon

Question 7

What is taxonomy?

Answer 7

Study of taxa and their positions in the hierarchical order

Question 8

What are the taxa within one hierarchy?

Answer 8

Domain - Kingdom - Phylum - Class - Order - Family - Genus - Species

Question 9

What is biodiversity?

Answer 9

Refers to the number and variety of living organisms in a particular area

Question 10

What are the 3 components of biodiversity?

Answer 10

1. Species diversity - the number of different species and number of individuals of each species within any one community
2. Genetic diversity - the variety of genes possessed by the individuals that make up a population of species
3. Ecosystem diversity - the range of different habitats, from a small local habitat to the whole of earth

Question 11

What do the terms genotype, phenotype and allele mean?

RECALL

Answer 11

Genotype - range of genes that make up a cell

Phenotype - expression of genotype and its interaction with environment

Alleles - specific version of a gene

Question 12

How is biodiversity measured?

Answer 12

Species richness and index of diversity

Question 13

What is species richness?

Answer 13

The number of different species in a particular area at a given time (community)

2 communities may have the same number of species but the proportions of the community made up of each species may differ

Question 14

What is a population and a community?

Answer 14

Population - group of organisms of same species occupying a particular area at a particular time that could interbreed

Community - involves all the different populations in an area

Question 15

What is index of diversity?

Give the equation

Answer 15

Both the number of species in a community and the number of individuals of each species in that community

D = N(N-1)/ sum of n(n-1)

Question 16

What does each letter stand for in D = N(N-1)/ sum of n(n-1)?

INDEX OF DIVERSITY

Answer 16

D = index of diversity
N = total number of organisms of all species
n = total number of organisms of each species

Question 17

How are agricultural ecosystems different to normal?

Answer 17

They are controlled by humans/ farmers which often select species in particular quantities to make them more productive

• low species richness and low index of diversity

Question 18

What are some farming techniques to reduce species diversity?

Answer 18

1. Hedgerow removal - as field gets bigger, these virtual habitats are removed
2. Monocultures - large areas of land taken up by one crop species
3. Pesticides + inorganic fertilisers - chemicals to kill pests that eat their crops, but do also kill non-target species
4. Deforestation - amazon rainforest being cleared for farming

Question 19

What are some conservation techniques that increase species and habitat diversity without raising food costs/ yields?

Answer 19

1. Maintain existing hedgerows at beneficial height and shape (A-shape better habitat than rectangular)
2. Plant hedges rather than fences for boundaries
3. Maintain ponds and create new ones
4. Leave wet corners of fields rather than draining them
5. Reduce use of pesticides - instead use biological pests/ GM organisms resistant to pests
6. Use crop rotation that includes nitrogen fixing crop - rather than fertilisers - to improve soil fertility