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Flashcards in Conservation Biology Deck (11):

what is conservation biology?

scientific discipline developed to deal with current biodiversity crisis


what is the dominant ecological force on the planet?



what is an invasive (alien) species?

an organism that causes ecological or economic harm in an area where it is not native

often thrives on relaxed selection pressures


what is overharvesting

some is legal and others are illegal and wildlife forensic techniques can identify perpetrators


when is a population in trouble?

small populations are vulnerable for a variety of factors

1) more genetic drift = less ability to adapt

2)more interbreeding depression

3) population more subdivided by fragmentation

4)more demographic variation

all cause lower effective population size which leads to extinction!!


what leads to lower effective population size? (Na)

- environmental variation
- catastrophic events
- habitat destruction
- environmental degradation
- habitat fragmentation
- overharvesting
- effects of exotic species
- environmetal variation
- catastrophic events


genetic drift and small populations

genetic drift is higher in small populations

leads to fixation of alleles and loss of heterozygosity


why is loss of heterozygosity such a bad thing?

interbreeding depression
1) inability to maintain heterozygosity at loci where there may be a heterozygote advantage
2) increased occurrence of deleterious recessives


effects of interbreeding depression

interbreeding depression affects different species in different way but is usually deleterious



by the 90's there were only 20-30 cougars in florida and there was low sperm counts, heart defects, and low kitten survival rates

so in 1995 8 female texas panthers were released into florida panther habitat that lead to the genetic restoration of the florida panther

the new females increased depleted genetic diversity, improved population numbers and reversed indications of inbreeding depression

heterzygosity doubled, survival and fitness measures improved, and interbreeding correlates declined


loss of sharks

due to overfishing

causing increased numbers of rays --> in the past scallops survived ray predation but increasing numbers of rays were enough to destroy all the scallops in some areas

also harming coral reefs because there is decrease in the herbivorous fishes which promote reef health

there is also an increase in mesopredators (smaller predators) --> usually lead to declining prey populations which can destabilize communities and drive local extinctions