Biodiversity and natural resources Flashcards
4.1 Human activities that threaten biodiversity?
Land development (habitat destruction, fragmentation, degradation)
Over-exploitation
Introduction of alien species
Pollution
4.2 Define biodiversity
Variety of living organisms
4.2 Define endemic
The state of a species being unique to a particular geographical location, such as an island, and not found anywhere else
4.2 Equation of heterozygosity index
H = number of heterozygotes/number of individuals in the population
4.2 Equation of index of diversity
D = N (N - 1) / sum of [n(n-1)]
N is total number of organisms
n is total number of organisms in each species
4.3 Define niche
The way an organism exploits (uses) its environment
4.3 Give an example of niche
Mirror orchids exploit behaviour of insects by pretending to be female wasps and attracting male wasps to pollinate the flowers as they try to mate
4.3 Define adaptations
Features that enable organisms to survive
4.3 Behavioural adaptation example
Changes in behaviour
Explosive seed dispersal of balsam and bitter crass
Herring gull chicks peck at red spot on parents’ beak causing them to regurgitate food
4.3 Physiological adaptation example
Changes in processes
Danish scurvy grass has adaptation allowing it to tolerate high salt concentrations, so they could occupy roadsides
Thermophilic bacteria are adapted to tolerate high temperatures in hot springs
4.3 Anatomical adaption example
Physical adaptations both internal and external
Bumblebees have long tongues to collect nectar, and have pollen baskets on their hind legs so pollen could be carried back for food for larvae
4.4 Define natural selection
The mechanism by which species change over time as they adapt to their environment
4.4 Define evolution
A change in allele frequency in a population over time (generations)
4.4 Process of evolution
Naturally occuring random mutations cause genetic variation in population
Environment change causes new selection pressures
Allele previously of no advantage now becomes advantageous
Organisms with advantageous allele more likely to survive and reproduce
Allele passed on to offspring
Allele frequency increases
4.4 Define gene pool
All the alleles present in a population
4.4 Define selection pressure
Any cause which reduces reproductive success
4.5 Hardy-Weinberg equation
p^2 + 2pq + q^2 = 1
p is frequency of dominant allele
p^2 is frequency of homozygous dominant individuals
q is frequency of recessive allele
q^2 is frequency of homozygous recessive individuals
2pq is frequency of heterozygous individuals
Always calculate recessive first
4.5 Process of reproductive isolation leading to speciation
A part of the population isolated by geographical features (e.g. high mountain range, river, ocean)
Prevents the group from breeding with the rest of the population
Different selection pressures lead to expression of different alleles
Random mutations accumulate
Eventually they are too different to interbreed and produce fertile offspring
A new species is formed
4.6 Define taxonomy
Placing organisms into groups based on shared features (differences and similaries in phenotypes and genotypes)
