Biodiversity Flashcards
(30 cards)
Define biodiversity
The number and variety of genes, species and habitats in a particular area
Define Community
All the living organisms present in an ecosystem at a given time
Define population
Group of individuals of the same species which live in a particular area at a given time
Define habitat
Where a population lives and which is characterised by physical conditions and the types of other organisms present
Define ecosystem
All living and non living components of a particular area
Define niche
all the conditions and resources required for an organism to survive and reproduce (its ‘role’ in the ecosystem)
Describes how an organism fits into its environment. It describes what a species is like, where it occurs, how it behaves, it’s interactions with other species and how it responds to its environment
Define species diversity
The number of different species and the number of individuals of each species with any one community
Define genetic diversity
Number of different alleles of each gene
The variety of genes possessed by the individuals that make up a population of a species
Define ecosystem diversity
Range of different habitats from a small local habitat to the whole of the earth
How do you assess genetic diversity
Compare base sequences of DNA, base sequence of mRNA and Amino acid sequences in proteins
How do you assess ecosystem diversity
Assess the range of different habitats and investigate these by recording measures of aerobic characteristics.
Define species richness
(A measure of species diversity)
The number of different species in a particular area at a given time
How does biodiversity reflect how well an ecosystem is likely to function
The higher the species diversity index the more stable and ecosystem:
They’re less affected by change because there’s a higher chance of at least one species surviving and therefore can maintain community
Is species diversity high or low in extreme environments?why?
Low. Communities are dominated by climatic factors rather than by organisms within the community
natural habitat Factors affecting biodiversity
Climate change
Interactions of invasive and non invasive species
Natural disasters
Man made habitat factors affecting biodiversity
Deforestation
Pollution
Climate change
Weakness of Simpson species diversity index
Makes no allowance for difference in sizes of individuals
Strength of Simpson species diversity index
It is quantitive- provides a number that makes it easier to compare the variety in different habitats
Takes into account species evenness as well as species richness
Impact of agriculture on biodiversity (5)
Low diversity index
Number of species, genetic variety of alleles decreases as farmers select species that have desired features
Economics- prioritise land available for the species with desired features- other species have to compete for spaces and resources
Pesticides
All leads to decrease in species diversity
Practices that have directly removed habitats and reduced species diversity
Removal of hedgerows
Creating monocultures- (monocultures are where only one crop is grown)
Filling in ponds/draining marsh
Overgrazing land- prevents regeneration of woodland
Use of pesticides and inorganic fertilisers
Absence of crop rotation and lack of intercropping
What is intercropping
Planting 2 diff crops in the same field
Cultural methods of pest control
Weeding
Crop rotation
Growing crops at a particular time in the life cycle of pests
Removing remains of crops and badly damaged plants which might harbour pests
Creating physical barrier
Intercropping
Covering soil with organic material-prevents light reaching weeds
How does crop rotation increase species diversity
Discourages the build up of several potentially damaging pest species- only effective when a pest can’t attack successive crops
Define pest
Undesirable organism
