Conservation Biology Flashcards
What does the History fo RCW reflect?
species that require specific habitat that is degraded via human activity will continue to shrink, in some cases, they vanish altogether
What is conservation biology?
the scientific study of
- biodiversity
- how human activities impact diversity
- how to maintain and prevent its loss
- how to reverse course
Why protect biodiversity?
- we, as humans, rely of biodiversity (food, fuel fibre, medicine, building materials, spices)
- moral obligation
Extinction
is a natural part of the evolutionary process
- evolution occurs from a balance of the end of species (via extinction) and the birth of new ones (speciation)
How do we quantify extinctions occurring periodically
“background rate of extinction”
- 10% of species are lost every 1 million years
- 30% every 10 million years
- 65% every 100 million years
Define Mass Extinction
a loss of over 75% of species within a geographically short period of time
-i.e., less than 2 million years
Name the ‘Big Five’ mass Extinctions
- end of the Ordovician
- Late Devonian
- End permian
- End Triassic
- End Cretaceous
End of the Ordovician
- 444 MYA
- 86% of species lost
- intense glacial and interglacial periods created large sea-level swings and moved shorelines dramatically
- the tectonic uplift of the Appalachian mountains created lots of weathering, sequestrian of CO2 and with it changes in climate and ocean chemistry
Late Devonian
- 360 MYA
- 75% species lost
- rapid growth and diversification of land plants generated and severe global cooling
Early Permian
- 250 MYA
- 96% of species lose
- intense volcanic activity in Siberia
- this caused global warming
- elevated CO2 and sulfur levels from volcanoes caused ocean acidification, acid rain, and other changes in ocean and land chemistry
End Triassic
- 200 MYA
- 80% of species lost
- underwater volcanic activity in the central atlantic magmatic province (CAMP) caused global warming and dramatic change in the chemical composition of the oceans
- often mistaken as the even that led to the extinction of the dinos
End Cretaceous
- 65 MYA
- 76% of species lost
- asteroid impact in Yucatan, Mexico
- caused a global cataclysm and rapid cooling
- some changes may have already pre-dated this asteroid, with intense volcanic activity and tectonic uplift
How many Species are on the 2022 IUCN Red list of threatened species?
42 108, at a minimum are at-risk
Biodiversity Crisis
when one species goes extinct, it affects other species and the ecosystem as a whole
What does it mean that Earth’s biota is becoming Homogenized?
the worldwide reduction in biodiversity due to spread of non-native and native generalists coupled with declining abundances and distributions of native specialists and endemics
How do non-native species have negative effects on native species diversity?
- range contractions
- small population size
Specialists vs. Generalists in native species?
- the biggest “losers” tend to be specialists
- the “winners” are generalists and cope with invasives
Fish in the US
fish species across the US are becoming more similar, largely due to the introduction of game fish across state lines
Threats to Biodiversity
- habitat
- invasive species
- Humans
- overexploitation
- pollution
- climate change
Habitat loss
- outright conversion of habitat into something else
- earth has been modified across 60% of its land surface
- one species, homo sapiens, appropriates approx. 25% of earths primary production
Habitat fragmentation
breaking up of once continuous habitat into a series of patches amid a human dominated landscape
Habitat Degradation
changes that reduce the quality of habitat for many, but not all species
What are Invasive Species
non- native, introduced species that sustain growing populations and have large effects on communities
Example of Invasive Species
Kudzu - “the plant that ate the south”
- climbing deciduous perennial vines
- vines grow so quickly that it smothers and kills them by blocking out most of the sunlight and taking up root space
- makes leaf little more labile, lessening carbon sequestration ability of the soil
Humans as a threat to biodiversity
- consumption of rare animals is linked to cultural traditions and/or considered a delicacy
- e.g., four species of sea turtle are traded off the gulf of venezuela for consumption purposes and are culturally significant to indigenous communities
Overexploitation as a threat to biodiversity
- collapse of the cod fishery in the Atlantic
- affects the pop. abundance and organism size (length of fish declined 50%)
Pollution as a threat to Biodiversity
pollution can exacerbate declines in species that are already reduced by habitat loss, invasive species, overexploitation
Bioaccumulation
an increase in the concentration of a chemical in an organism over time because the chemical is not metabolized or excreted
Biomagnification
increasing tissue concentrations of chemicals in successively higher trophic levels as animals at each trophic level consume prey with higher concentrations
What is DDT
- first of the modern synthetic insecticides in the 1940s
- was initially used with great effect to combat malaria, typhus, and other insect borne human disease
- was also effective for insect control in crop and livestock production, institutions, homes and gardens
What kind of effect does DDT result in?
- shell-thinning due to bioaccumulation up the food chain
- bird shells would unable to support the weight of the incubating bird; when mother would sit on the eggs, they would break
- bird pop. rebounded after DDT was banned (1972), but DDR also lasts for a long time in environments
Why are small populations more prone to extinction?
small population are more prone to extinction than large ones due to drift , inbreeding and/or increased frequency of deleterious alleles
“genetic rescue” of the Florida Panther
- pop. down to 25 in early 90’s
- had low genetic diversity and a high frequency of problems such as heart defects, kinked tails, poor sperm quality and adult males in which one or both testes failed to descend properly
- 8 female pumas from texas were released into florida (resulted in pop size tripling, genetic variation double, genetic abnormalities overall decreased)
what is Population Viability Analysis?
- demographic model
- projection of the potential future status of a pop
- often used to estimate the likelhood that a population will persist under different management scenarios
Ex Situ Conservation
- a last resort measure to rescue species on the brink of extinction
- taking animals out of original habitat, allowing them to multiple in sheltered conditions under human care
- ex. california condor
Where do Ex situ programs take place?
zoos, special breeding facilities, botanical gardens and aquaria throughout the globe
What kind of problems do Ex situ programs introduce?
- very expensive
- do not always result in restoration of self-sustaining wild pop.
- captive animals may be: exposed to novel diseases, genetic adaptation to captivity, behavioral changes
How are species ranked for protection?
- distinctiveness/ irreplaceability
- vulnerability
- utility
How does a species serve as a surrogate species?
- flagship species - species that capture public attention, have symbolic value, and/or are important for ecotourism
- umbrella - protecting a species’ habitat will serve to protect the habitat requirements for many other species
