Conservation biology Flashcards
What is conservation biology?
Multidisciplinary science developed to deal with alarming loss in biodiversity
What are the 2 major goals of conservation biology?
> Investigate human impacts on biodiversity
>Develop approaches to prevent biodiversity loss
What are the 3 levels of biodiversity loss?
> loss in genetic diversity
loss in species diversity
ecosystem loss
(loss in levels affects one another)
What are the 2 patterns of extinction in the geological record?
Background extinction
= long pattern of ecosystem change that leads to some species going extinct
= normal extinction rate
Mass extinction
= catastrophic spikes of extinction with sudden widespread ecosystem change
What is the opposing argument to us being in the 6th mass extinction?
No. of genera increasing over time
BUT this is due to finding new orgs and making a new genera to describe them
What is the current extinction rate?
1 species an hr
27000 species a yr
100-10,000x background rate
How is genetic diversity within species lost?
Reduction in effective population sizes
-> smaller no. of alleles in population
= higher chance of going extinct
What are the 4 major threats to species loss?
> Habitat loss/degradation (incl. pollution)
> Introduced species (incl. disease)
> Overexploitation (harvesting/hunting)
> Climate change
Which is the biggest threat to species?
Habitat loss + degradation
98% of land suitable for agri has been transformed
What affect does fragmentation have?
Causes reduction in population sizes + genetic diversity
-> increases likelihood of local extinction
+ eventually global extinction
What are the 3 types of pollution?
Land
- release of chemicals leaves areas unusable by orgs
Air
Water
- eutrophication + dead zones
Why are introduced specie a problem?
>Displace native species >Have fewer predators/pathogens >Disrupt ecosystem function >Reduce overall diversity >Transmit disease
What is overexploitation?
Humans taking wild plants + animals at rate that exceeds system’s ability to replace them
Which orgs are most susceptible to overexploitation?
Large orgs with slow reproductive rates
What limits a species’ distribution?
Energetic costs
Resource availability
Fitness higher under optimal conditions
What are the possible outcomes if climate conditions change?
> Range shifts = ranges where species are present
Plastic responses = change response to environment w/out changing genetic make-up
Adaptation = change eugenic make-up
Extinction
What are the 3 mechanisms of extinction categories for single populations?
Demographic uncertainty
Environmental uncertainty
Loss of genetic diversity
What is a metapopulation?
Who introduced this concept?
a group of populations that are separated by space but consist of the same species
Levins
What is the source/sink model of metapopulations?
What is the landscape model?
Source populations provide excess individuals which emigrate to + colonise subpopulations
Matrix varies in permeability
What does metapopulation survival depend on?
Local population survival
-> increases w/ patch size
Unoccupied sutabale habitat at suitable distances
Sufficient migration for colonisation of unoccupied habitat to occur
-> increases w/ small distances + corridors
What are the 4 genetic factors affecting small populations?
Genetic drift
Founder effects
Bottleneck effects
Inbreeding depression
What is genetic drift?
Change in freq of an allele in a population due to random sampling
- increases chance of alleles being lost
- significant in small populations
What is the equation for effective population size?
Ne = (4Nf x Nm) / (Nf + Nm)
What is the founder effect?
When few individuals become isolated from the larger population to form new one
-> allelic diversity
What is the bottleneck effect?
Sudden reduction in population size due to change in environment
What is inbreeding depression?
Relative reduction in fitness of inbred progeny in comparison to an equivalent outbred progeny
