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1. Physically diverse habitat, moderate disturbances, little variation in resources, middle stages of
succession and evolution
How have human activities affected global biodiversity?
1. __________- Habitat fragmentation, Invasive Species, human Population, Pollution and Overharvesting
How can we reduce biodiversity loss?
1. Preserve/restoring ecosystems
22-2 Species Extinction
What are three types of species extinction?
1. Local extinction- species no longer found in a particular area, Ecological extinction- species no longer
plays an ecological role in communities due to too few members, Biological extinction- no longer found
anywhere on Earth, gone forever
What are endangered and threatened species?
1. Endangered- has so few individuals, that species could become biologically extinct; Threatened- still
abundant in its natural range but declining in number and may become extinct
How do biologists estimate extinction rates?
1. Evolutionary biologists estimate 99.9% of all species that ever existed are extinct due to background
extinction rate, mass extinctions, and extinction spasms (mass extinctions in less than 1,000 years)
2. Mass extinctions can promote biodiversity- adaptation radiation- 5 million years, based on fossil record
for biological diversity to rebuild after a large loss
3. Estimating species extinction rate are based on observations, i.e. if 90% of habitat is removed, 50% of
all species will disappear; using population viability models through computer simulations and
minimum dynamic area
What effects are human activities having on extinction rates?
1. Before humans, background extinction was .0001% per year, humans have increased it to .1% (1000x
more); amounts to 5,000 species per year on a conservative basis; 50% of all species could be eliminated
by 2100
Bats are getting a bad rap
1. Vulnerable to extinction- reproduce slowly, and live in large groups (White Nose Syndrome); play an
important niches as pollinators and pest reducers (insects); bats need to be viewed as an ally not as
enemies
22-3 Why Should We Care About Biodiversity?
Why preserve wild species and ecosystems?
1. It will take 5 million years for a speciation to rebuild biodiversity; they have instrumental valueusefulness to us; intrinsic value- they exist, regardless of whether they have any usefulness to us
What are the instrumental values of biodiversity?
1. Economic goods-provide foods, fuel, fiber, lumber, paper, medicine
a. 40% of all medicines and 805 of the top 150 prescription drugs were derived from living organisms
in mainly tropical developing countries
1) World‟s flowering plants have alkaloids, a class of natural chemicals that are potent agents
against cancer and other diseases, i.e. Pacific yew- ovarian cancer, Cinchona- malaria treatment,
Rosy Periwinkle-, Hodgkin‟s disease and lymphocytic leukemia
2. Ecological Services- pollination, soil formation, nutrient recycling, pest control, climate regulation,
flood control, clean water, waste decomposition, clean air, etc.
3. Information- genetic information allows us to produce new foods, and vaccines
4. Recreation- Nature photography, nature walks, bird-watching; i.e. American spend 3x more to watch
wildlife than watching movies/professional sporting events
a. _________________- $500 billion industry; i.e. one male lion generates $515,000 in tourist dollars
over 7 years in Kenya but only $1,000 if killed for its skin
5. Nonutilitarain values- existence- we find value knowing that a redwood forest even we don‟t ever see
one; aesthetic- nature‟s beauty; bequest- people are willing to pay to protect natural capital