Biodiversity

Question 1

Biodiversity

Answer 1

The number of species and the number of individuals of each species in a given environment

Question 2

The Binomial system

Answer 2

Gives organisms a unique name with two parts, the genus and the species

-Genus always begins with a capital and species is always lowercase

Question 3

Biodiversity varying over time

Answer 3

Succession: A change in the composition of a community

• Organisms change to more suitable habitats
• Animal biodiversity increases, and plant biodiversity decreases

Natural selection: Species that are more suited to their environment survive and evolve over time to form new species whilst other species die

Human factors:

• Agriculture/misuse of land
• Deforestation
• Overfishing
• Pollution of rivers

Question 4

Agriculture/misuse of land

Answer 4

Reduces biodiversity:

• Land is dominated by one species
• There is less space for other species
• Hedgerows are removed which have high biodiversity

Question 5

Deforestation

Answer 5

Reduces biodiversity:

-Forests provide a variety of different habitats

Question 6

Overfishing

Answer 6

Reduces biodiversity:

• Fish removed from water at a faster rate than they can replenish
• Trawlers dredging ocean floors disrupts habitats

Question 7

Pollution of rivers

Answer 7

Reduces biodiversity:

• Organisms are killed directly
• Organisms killed indirectly due to bioaccumulation of toxins
• Organisms’ fertility affected adversely
• Resources used by organisms are killed off

Question 8

Diversity index formula

Answer 8

Species Diversity index = 1 - [Sum of n(n-1)] / N(N-1)

Question 9

Simpson’s diversity index

Answer 9

• Used to investigate the biodiversity of a habitat
• All values between 0 and 1
• Low values suggest low diversity
• High values suggest higher diversity

Question 10

Polymorphism

Answer 10

The occurrence of more than one phenotype in a population that cannot be accounted for by mutation alone, as a result of polymorphic genes

Genetic biodiversity can be assessed by determining:

• The number of alleles at a locus
• The proportion of the population that have a particular allele

Question 11

Molecular Assessment of Biodiversity

Answer 11

DNA fingerprinting:

• Researchers collect samples of DNA of a population and then analyse the base sequences
• The greater the variation in base sequence, the greater the genetic diversity

Question 12

Natural Selection

Answer 12

Only the best adapted organisms tend to survive and transmit their genes to succeeding generations, while the less adapted are eliminated.

Question 13

Adaptive traits

Answer 13

All species are adapted to the environment they inhabit, including anatomical, physiological and behavioural adaptions

Question 14

Anatomical traits

Answer 14

Animals:

• Sharks and penguins have streamlined bodies
• Makes them efficient at catching food

Plants:

• Some plants have honey or nectar guides called beelines
• They indicate the centre of the flower and attract more pollinators

Question 15

Physiological traits

Answer 15

Animals:

• Mammals and birds are endothermic
• They must avoid wasting energy when it is cold
• Some hibernate or migrate

Plants:

• Deciduous tress lose their leaves when the temperature and light intensity decrease in autumn
• This prevents water loss through transpiration and risk of dehydration from frozen water

Question 16

Behavioural traits

Answer 16

Animals:
-Some perform mating rituals to increase their chances of reproducing e.g. Peacocks displaying feathers

Plants:
-Many flower in spring when pollinating insects emerge, so they are pollinated