Biodiversity

Question 1

What is a species?

Answer 1

• They are capable of breeding to produce living, fertile offspring.

Question 2

What system is used for identifying organisms?

Answer 2

• Binomial system
• Organisms are defied by two names

Question 3

What are the features of the binomial system?

Answer 3

• It is a universal system based upon Latin or Greek names
• The first name, called the generic name, denotes the genu sto which the organisms belongs.
• The second name, called the specific name, denotes the species to which the organism belongs to.

Question 4

What are some rules that are applied to the use of the binomial system in scientific writing?

Answer 4

• In italics or if handwritten underlined
• First letter of the generic name is in upper case but the specific name is in lower case
• If the specific name is not known , it can be written as ‘sp’

Question 5

Why is courtship behaviour important?

Answer 5

• recognise members of their own species
• identify a mate that is capable of breeding and that is sexually mature
• form a pair bond that will lead to successful mating and raising of offspring
• synchronise mating so that it takes place when there is the maximum probability of the sperm and egg meeting
• become able to breed by bringing a member of the opposite sex into a physiological state that allows breeding to occur.

Question 6

What is classification?

Answer 6

The grouping of organisms

Question 7

What is taxonomy?

Answer 7

The theory and practice of biological classification

Question 8

What are the two main forms of classification?

Answer 8

Artificial classification and Phylogenetic classification

Question 9

What is meant by artificial classification?

Answer 9

• Where organisms are divided according to differences the are useful at the time
• These differences are called analogous characteristics where they have the same function but do not have the same evolutionary origins.

Question 10

What is meant by phylogenetic classification?

Answer 10

• Based on 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 the groups are contained within larger composite groups with no overlap
• Relationships in a phylogenetic classification are partly based on homologous characteristics.

Question 11

What are homologous characteristics?

Answer 11

Characteristics that have similar evolutionary origins regardless of their functions

Question 12

What is a taxon?

Answer 12

• Each group within a phylogenetic biological classification

Question 13

What are the different taxonomic ranks?

Answer 13

1. Domain -> Bacteria, Archaea and Eukarya
2. Kingdoms -> Protoctista, Fungi, Plantae and Animalia
3. Phyla -> eg Chordata
4. Classes -> Mammalia
5. Orders -> Carnivora
6. Families -> Felidae
7. Genera -> Felix
8. Species -> tigris

Question 14

What is phylogeny?

Answer 14

• The hierarchical order of taxonomic ranks is based upon the supposed evolutionary line of descent of the group members.
• This evolutionary relationship is called phylogeny.

Question 15

How is the phylogenetic relationship of different species represented ?

Answer 15

• Usually represented by a tree-like diagram called a phylogenetic tree.
• The oldest species is at the base of the trees while the most recent ones are represented by the ends of the branches.
• The closer the branches, the closer the evolutionary relationships.

Question 16

What are some difficulties involved in defining species?

Answer 16

• Species are not fixed forever but change and evolve over time.
• Within a species there can be considerable variation among individuals.
• Many species are extinct and most of these have left no fossil record.
• Some species rarely reproduce sexually.
• Members of different populations of the same species may be isolated and so never meet and therefore never got the opportunity to interbreed.
• Some types of organism are sterile.

Question 17

What is meant by biodiversity?

Answer 17

The general term used to describe variety in the living world.

Question 18

What is meant by species diversity?

Answer 18

• The number of different species and the number of individuals of each species within any one community

Question 19

What is meant by genetic diversity?

Answer 19

• The variety of genes possessed by the individuals that make up a population of a species.

Question 20

What is meant by ecosystem diversity?

Answer 20

• The range of different habitats, from a small local habitat to the whole of the Earth.

Question 21

What is species richness?

Answer 21

It is the number of different species in a particular area at a given time (community).

Question 22

Why is species richness not a good way to measure diversity?

Answer 22

• Because two communities may have the same number of species but the proportions of the community made up of each species may differ.

Question 23

What is the equation for the index of diversity?

Answer 23

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

where:
d = index of diversity
N = total number of organisms of all species
n = total number of organisms of each species

the higher the value d, the greater the species diversity

Question 24

How does biodiversity reflect how well an ecosystem is likely to function?

Answer 24

• The higher the species diversity index, the more stable an ecosystem usually is and the less it is affected by change.
• If there is a change in the environment it is more likely that there is one species which is able to tolerate the change in a community with a high diversity index than in a community with a low diversity index.
• Therefore at least one of the species is likely to survive. `