Transcript Biodiversity

Biodiversity
Biodiversity is the genetic,
species and ecological variation
of the organisms in a given area.
Charles Darwin
Diversity can be
explained by the
Theory of Evolution
Genetic diversity produces
phenotypic diversity
Niche specialization can lead to 
Species Diversity
leopard frog:
found in lakes, rivers, ponds,
streams, wetlands
tailed frog:
only in cold, clear mountain
streams sensitive to siltation,
warming
Giant kelp bed
Close to the surface
On the bottom
Tropical Rainforest
Deciduous
Forest
Artificial Selection has a Goal
Natural Selection does not
What is the relationship between
diversity and ecological stability.
Method of Study
Two test plots one with alot of diversity the other with
little diversity.
Monitor stability (interspecific competition) over time
in stress
without stress
Must ask question Is the type of species important
High Biodiversity implies many different
species
High Biomass has a lot of organisms
irregardless of type. If total weight taken it
could be quite high.
Biodiversity is due to or affects the
following
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Genetic Diversity: A measure of the variety of
different versions of the same genes within
individual species
Species Diversity: Describes the number of
different kinds of organisms within individual
communities or ecosystems
Ecological Diversity: Assesses the richness
and complexity of a biological community

A species is all the organisms of the same
kind able to breed in nature and produce
live, fertile offspring
How Many Species Are There?
There are about 2.1 million species
presently known, which is a small fraction
of the total that probably exists
 10-15% of the world’s species live in North
America and Europe
 The centers of greatest biodiversity tend to
be in the tropics

Drugs and Medicines

Certain anticancer alkaloids are derived
from the Madagascar periwinkle 13.5
Aesthetic and Cultural Benefits
Nature appreciation is economically
important
 Existence Value: The knowledge that a
species exists

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This may be reason enough to protect and
preserve it
What Threatens Biodiversity?
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Extinction: The elimination of a species
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This is a natural process
99% of all species that ever existed are now
extinct
Habitat Destruction
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Habitat fragmentation divides populations
into isolated groups that are vulnerable to
catastrophic events 13.8
Hunting and Fishing
Over harvesting is responsible for depletion
or extinction of many species
 Steam ships and explosive harpoons have
made it possible to catch and kill even the
fastest whales 13.11

Commercial Products and Live
Specimens
A variety of commercial products are
obtained from nature
 Smuggling of furs, hides, horns, live
specimens, and folk medicines amounts to
millions of dollars each year
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Predator and Pest Control
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Some animals have been greatly reduced
because they are regarded as dangerous to
humans or livestock or because they
compete with our use of resources
Exotic Species Introductions
Exotic species are considered to be among
the most damaging agents of habitat
alteration and degradation in the world
 Alien species from around the world now
threaten native species throughout the Great
Lakes 13.17
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Diseases
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Pathogens may also be considered predators
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To be successful, a pathogen must establish a
balance in which it can reproduce, but does not
destroy its host
Dutch elm disease caused towns to lose all of
their trees
Pollution
Toxic pollutants can have disastrous effects
on local population of organisms
 Lead pellets have been ingested by bottom
feeding waterfowl, which ultimately results
in lead poisoning
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Genetic Assimilation
Genetic Assimilation: The disappearance
of a species as its genes are diluted through
crossbreeding with a closely relate species
 Hatchery raised trout often are introduced
into streams and lakes where they
genetically dilute indigenous stocks

The Endangered Species Act
Endangered Species: Species considered to
be in imminent danger of extinction
 Threatened Species: Species that have
declined significantly in total numbers and
may be on the verge of extinction in certain
localities
 Vulnerable Species: Species that are
naturally rare or have been depleted by
human activities to a level that puts them at
risk
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Recovery Programs
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Species Recovery Plan: Describes how
species can be restored to numbers that
permit its delisting from the endangered
species list
Minimum Viable Populations
Island Biogeograghy: A species composed
of a small number of individuals can
undergo catastrophic declines due to
environmental change, genetic problems, or
random events when isolated in a limited
geographic range.
 Founder Effect: Occurs when a few
individuals establish a new population

Demographic Bottleneck: Arises when
only a few individuals survive some
catastrophe
 Genetic Drift: A reduction in gene
frequency in a population due to unequal
reproductive success
 Inbreeding: Mating of closely related
individuals resulting in recessive deleterious
mutations
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Habitat Protection
In Hawaii, where more than 50% of the land
is federally owned, many vegetation types
occur completely outside of natural
preserves 13.23
 Gap Analysis: Wildlife managers and
conservationists look for unprotected
landscapes that are rich in species
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Captive Breeding and Species
Survival Plans

Most mammals in North American zoos are
produced by captive breeding programs
instead of being captured in the wild