APES Chapter 11: Biodiversity and Conservation Biology
What are the trends in biodiversity? What areas tend to have more biodiversity? What
leads an area towards more diversity?
● Some groups of organisms include more species than others
○ Ex. insects show predominance over all other forms of life
■ 40% are beetles; beetle species alone outnumber all non-insect
animal species and all plant species
● Large numbers of species formed rapidly as populations spread into a variety of
environments and adapted to local conditions
● Other groups diversity because of a tendency to become subdivided by barriers
that promote speciation
● Other groups accumulated species through time because of low rates of
extinction
● Biodiversity greater in some places than in others
○ Ex. species richness generally increases as one approaches the equator;
latitudinal gradient in species richness
○ Some scientists argue that the tropics provide more room for speciation
○ Some scientists argue that solar energy promotes more plant growth,
making the areas near the equator more productive
○ Some scientists argue that the relative stability of tropical climates
discourages small numbers of generalist species from dominating
ecosystems and instead allows numerous specialist species to coexist
○ Some scientists argue that polar and temperate regions are relativelyspecies poor because glaciation events repeatedly forced organisms out
of these regions toward tropical latitudes
○ Tropical dry forest and rainforest support far more species than tundra
and boreal forests
○ Tropical biomes typically show more evenness; whereas high-latitude
biomes with low species richness, particular species greatly outnumber
others
■ Ex. Canada’s boreal forest dominated by immense expanses of
black spruce
■ Ex. Panama’s tropical forest contains hundreds of tree species,
none which greatly outnumber others
○ Species diversity tends to increase with diversity of habitats for the reason
that each habitat supports a somewhat different set organisms
○ Ecotones tend to support high biodiversity
■ Human disturbance often creates ecotones or patchwork
combinations of habitats
■ Increases habitat diversity locally
■ In moderately disturbed areas; species diversity tends to rise
■ At larger scales, human disturbance decreases diversity because it
replaces regionally unique habitats with homogenized disturbed
habitats, causing species reliant on the regionally unique habitats
to disappear
○ Structurally diverse habitats tend to allow for more ecological niches,
thereby supporting great species richness and evenness
■ Ex. forests generally support more diversity than grasslands
■ Ex. coral reefs support more diversity than open ocean
What are the benefits of biodiversity?
● Provides the food we eat
○ Humans have used at least 7000 plant species and several thousand
animal species for food
○ Modern industrial agriculture has narrowed diet
■ 90% of our food from just 15 crop species and eight livestock
species
■ Lack of diversity leaves humans vulnerable to crop failures
■ Can improve food security (the guarantee of an adequate, safe,
nutritious, and reliable food supply) by finding sustainable ways to
harvest or fam wild species and rare crop varieties)
■ New/underused food sources exist worldwide
● Ex. babassu palm of the Amazon produces more vegetable
oil than any other plant
● Ex. serendipity berry generates a sweetner 3000 times
sweeter than table sugar
● Some tolerant grasses and trees are so fardy that farmers
can irrigate them with salt water to produce animal feed
● Wild relatives of our crop hold reservoirs of genetic diversity
that can help protect the crops we grow in monocultures by
providing helpful genes for cross breeding or genetic
engineering
● Already received tens of billions of dollars worth of disease
resistance from wild relatives of potatoes, wheat, corn,
barely, and other crops
List potential food sources
● Amaranths (three species of Amaranthus)
○ Grain and leafy vegetable; livestock feed; rapid growth, drought resistant
● Buriti palm (Mauritia exuosa)
○ “Tree of life” to Amerindians; vitamin-rich fruit; pith as source for breath;
palm heart from shoots
● Maca (Lepidium meyenii)
○ Cold-resistant root vegetable resembling radish; with distinctive flavor;
near extinction
● Capybara (Hydrochoeris hydrochaeris)
○ World’s largest rodent; meat esteemed; easily ranched in open habitats
near water
● Vicuna (Lama vicugna)
○ Threatened species related to llama; source of meat, fir, and hides; can be
profitably ranched
● Chachalacas (Ortalis, many species)
○ Tropical birds; adaptable to human habitations; fast growing
List potential plant pharmaceuticals and their application
● Pineapple (Ananas comosus)
○ Drug: Bromelain
○ Application: Controls tissue inflammation
● Autumn crocus (Colchicum autumnale)
○ Drug: Colchicine
○ Application: Anticancer agent
● Yellow cinchona (several species of Cinchona)
○ Drug: Quinine
○ Application: Antimalarial agent
● Pacific yew (taxus brevifolia)
○ Drug: Taxol
○ Agent: Anticancer agent (especially ovarian cancer)
● Velvet bean (Mucuna deeringlana)
○ Drug: L-Dopa
○ Application: Parkinson’s disease suppression
● Common foxglove (Digitalis purpurea)
○ Drug: Digitoxin
○ Application: Cardiac stimulant
List potential animal pharmaceuticals and their application
● Amphibians
○ 30% of all species are threatened with extinction
○ Potential Medical Uses:
■ Antibiotics; chemicals for painkillers, heart disease, and high blood
pressure
■ Natural adhesives for treating tissue damage
■ Ability to regenerate organs and tissue could suggest how we
might too
■ “Antifreeze” compounds that allow frogs to survive freezing might
help us preserve organs for transplants
● Sharks
○ Overfishing has reduced populations of most species; some risk
extinction
○ Potential Medical Uses:
■ Squalamine from sharks’ livers could lead to novel antibiotics,
appetite-suppressants, drugs to shrink tumors, and drugs to fight
vision loss
■ Study of salt glands is helping address kidney diseases
● Horseshoe crabs
○ Overfishing is sharly diminishing populations
○ Potential Medical Uses:
■ A number of antibiotics are being developed
■ The compound T140 may treat AIDS, arthritis, and several cancers
■ Cells from blood can help detect cerebral meningitis in people
● Bears
○ Nine species are at risk of extinction
○ Potential Medical Uses:
■ An acid from bears’ gallbladders treats gallstones and liver disease,
and prevents bile buildup during pregnancy
■ While hibernating, bear build bone mass. If we learn how, we might
apply this knowledge to treat osteoporosis and hip fractures.
■ Hibernating bears excrete no waste for months. Learning how
could help treat renal disease.
● Cone snails
○ Most live in coral reefs; threatened ecosystems
○ Potential Medical Uses:
■ One compound may prevent death of brain cells from head injuries
or strokes
■ Another is a painkiller 1000 times more potent than morphine
Review ecosystem services and ethics
● Forests provide clean air and water, bugger hydrologic system against flooding
and drought
● Native crop varieties provide insurance against disease and other stresses
● Wildlife attracts tourism and boosts economies
● Biodiversity helps to:
○ Provide food, fuel, fiber, and shelter
○ Purify air and water
○ Detoxify and decompose wastes
○ Stabilize Earth’s climate
○ Moderate floods, droughts, and temperatures
○ Cycle nutrients and renew soil fertility
○ Pollinate plants, including crops
○ Control pests and diseases
○ Maintain genetic resources for crop varieties, livestock, breeds, and
medicines
○ Provide cultural and aesthetic benefits
● Economic value of 17 of the world’s ecosystem services estimated at more than
$143 million per year
○ More than GDP of all national economies combined
● Biophilia: human beings share an instinctive love for nature and feel an emotional
bond with other living things
● People believe that living organisms have inherent right to exist (intrinsic value)
What are the characteristics of winners and losers?
● Creatures that benefit from changes we make in biodiversity, and those harmed,
each tend to show predictable sets of attributes, because impacts share
common themes
● Humans shape diverse environments to our own needs and tastes
○ More open in structure; make room for farms, pastures, towns, and cities
○ Leave pollution in our wake
● Winners tend to be…
○ Generalists
○ Geographically widespread
○ Users of open, early successional habitats
○ Able to cope with rapidly changing conditions
○ Small and fast-reproducing (r-selected)
○ Low on the food chain
○ Not in need of large areas of habitat
○ Mainland species
○ Ex. house mouse
● Losers tend to be…
○ Specialists
○ Limited to a small range
○ Users of mature, dense habitats
○ Needing stable unchanging conditions
○ Large and slow reproducing (K-selected)
○ High on the food chain
○ Needing large areas of habitat
○ Island species
○ Ex. tiger
What are extinctions?
● Occurs when the last member of a species dies and the entire species ceases to
exist
● Local extinction/extirpation: Disappearance of a particular population from a
given area, but not the entire species globally
○ Can lead to extinction over time
○ Ex. black rhinoceros in Africa
■ Three subspecies extinct
How often have major extinction events occurred, what was affected, and what are
some causes? Know the Permo-Triassic and Cretaceous-Paleogene extinctions.
● In the past 440 million years, five major mass extinctions
○ Eliminated more than one-fifth of life’s families; at least half of species
● Most severe episode: end of Permian period
○ 250 million years ago, close to 90% of species went extinct
● Best-known episode: end of Cretaceous period
○ Evidence points to an asteroid impact (possibly volcanism)
○ Brought an end to dinosaurs
What is the 6th mass extinction and what is causing it?
● If current trends continue, modern era, known as Quaternary period, may see
extinction of more than half of all species
●
What are major causes of biodiversity loss? List and describe 5.
Class project on invasive species
Describe Conservation Biology
Endangered Species Act what is it, what has it done and what are the pros and cons?
1973 Convention on International Trade in Endangered Species of Wild Fauna and Flora
(CITES)
1992 Convention on Biological Diversity
Captive Breeding
Forensic Science Role?
Strategies for protection
Umbrellas and Flagships
Biodiversity Hotspots (more in January)
Parks and protected areas
Ecological restoration