Biodiversity,
Human Impact,
and Conservation
Lecture 1: Biodiversity
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Biodiversity is the variation of lifeforms within a given
ecosystem.
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Genetic Diversity: individual genetic variation within a population
and the genetic variation between populations
Species Diversity: the variety of species in an ecosystem
Ecosystem Diversity: the variety of the biosphere’s ecosystems
An Ecosystem is the sum of all the organisms in a given
area as well as the abiotic factors with which they interact.
A Biodiversity Hotspot is a relatively small area with an
exceptional concentration of endemic species and a large
number of endangered or threatened species.
Endemic Species: A species only found in one region or
part of the world
Ecology is the study of the interactions between
organisms and the environment.
Understanding Ecology
• Studying ecology will reveal the richness of the biosphere.
• Ecological interactions can determine both the distribution
of organisms and their abundance.
• With this understanding, one will be able to help conserve
and sustain biodiversity.
Determining Species Distribution
and Abundance
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1) Environmental Factors
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Temperature
Seasonality
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2)Amount and Variability of
Precipitation
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Dispersal contributes to this
global distribution of
species.
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Above: Biogeographic
realms indicating
distribution patterns due
to continental drift and
topographic land barriers
Flowchart of Factors Limiting
Geographic Distribution
Understanding the Flow Chart:
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Behavior Limits: refer to habitat selection
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Biotic Factors: mainly refer to predation
and the presence or absence of food
resources but may also include parasitism,
disease, or competition
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Abiotic Factors: include temperature, water,
sunlight, wind, and climate conditions
Climate mainly determines the
Distribution and Structure of
Ecosystems
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Temperature and
precipitation in
addition with physical
geographic features
determine the
structure of terrestrial
Biomes
Introduction to The Tropics
Tropics are the location of many biodiversity
hotspots because of their unique structure and
history that resulted in species diversity.
50% of the worlds species are found in the tropical
rainforests.
Tropical Rainforests as Hotspots
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There are 3 main regions of
tropical rainforests
• 1)The Americas
• 2)Africa
• 3)Australasia
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The Conservation
International has
established global hotspots.
• An interactive map can be found
here:
http://www.biodiversityhotspots.
org/Pages/default.aspx
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Biodiversity is not limited to
animal species but plant
species as well.
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Tropical Rainforests are
comprised of 100-300+
species of trees pre hectare.
And few trees are common,
while many are rare
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The Tropical Rainforests
have increased faunal
diversity and density
Effects of Faunal Groups
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Direct contribution to species richness
Indirect effects on plant and animal diversity
Contribute substantially to total biodiversity
of Rainforests
Contribute irreplaceable services such as
seed dispersal, seed predation, and seed
pollination
In summary, the faunal composition effects
how ecosystems function
Like faunal groups effect Tropical
Rainforests, marine ecosystems
are affected by Coral Reefs
Coral Reefs are among the most
Diverse Ecosystem
• Coral Reefs are the richest in species of any
marine environment
• Coral Reefs are the keystone species of the
marine environment
– Note a keystone species is a species whose
presence has a disproportionate effect on the
ecosystem and contributes to the diversity of the
ecosystem. Without this species, there is a
direct correlation to extinction in other species
Coral Reefs, The Hotspot
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Coral Reefs only comprise 0.2%
of the Earth’s Ocean Surface and
they almost exclusively occur
within the Tropics
Abundance and Distribution is
strongly affected by temperature
The Current Distribution of
Coral Reefs is shown to the right.
-Caribbean
-Coast of Central America
-Indo-Pacific Waters
-East Coast of Australia
Biodiversity is Effected
by Several Biotic and
Abiotic Factors, but
the Greatest Threat to
Biodiversity is Human
Impact