Biodiversity Flashcards
Biodiversity
The number of species and the number of individuals of each species in a given environment
The Binomial system
Gives organisms a unique name with two parts, the genus and the species
-Genus always begins with a capital and species is always lowercase
Biodiversity varying over time
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
Agriculture/misuse of land
Reduces biodiversity:
- Land is dominated by one species
- There is less space for other species
- Hedgerows are removed which have high biodiversity
Deforestation
Reduces biodiversity:
-Forests provide a variety of different habitats
Overfishing
Reduces biodiversity:
- Fish removed from water at a faster rate than they can replenish
- Trawlers dredging ocean floors disrupts habitats
Pollution of rivers
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
Diversity index formula
Species Diversity index = 1 - [Sum of n(n-1)] / N(N-1)
Simpson’s diversity index
- Used to investigate the biodiversity of a habitat
- All values between 0 and 1
- Low values suggest low diversity
- High values suggest higher diversity
Polymorphism
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
Molecular Assessment of Biodiversity
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
Natural Selection
Only the best adapted organisms tend to survive and transmit their genes to succeeding generations, while the less adapted are eliminated.
Adaptive traits
All species are adapted to the environment they inhabit, including anatomical, physiological and behavioural adaptions
Anatomical traits
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
Physiological traits
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
