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Biodiversity
Variety of the earth’s species, the
genes they contain, the
ecosystems in which they live,
and the ecosystem processes
such as energy flow and nutrient
cycling that sustain all life.
Hot Spots
A
hotspot is an area where there are
many threatened and endangered
species
 There are currently 34 hotspots in the
world today
Species Diversity
 Number
and abundance of species
present in different communities
Ecological Diversity
 The
variety of terrestrial and aquatic
ecosystems found in an area or on the
earth
Functional Diversity
 The
biological and chemical processes
such as energy flow and matter recycling
needed for the survival of species,
communities and ecosystems

Food Chains & webs
Genetic Diversity
 The
variety of genetic material within a
species or a population
Theory of Natural Selection
 Explains
how life has evolved from a
common ancestor
Survival of the fittest
 Organisms
suited for the environment will
survive to reproduce, thus passing down
desirable traits.

Examples:
 Giraffes
 Camels
 Influenza
virus
 Venus fly trap
 NOTE
– fittest does not equal strongest!!!
Natural Selection and
Geological Processes
 Location
on the earth influences
biodiversity (rainforest vs. tundra)
 Continental movement

Earthquakes and volcanoes
 Climate

change
Cyclic cooling and heating of the earth
 Catastrophic

events
Asteroid impacts, major volcanic eruptions
Continental movement
 Theory
of Continental Drift
 The earth has large plates located
between the lithosphere and
asthenosphere
 These plates move very slowly (1-3cm/yr)
 This creates oceans, mountain ranges,
volcanoes, earthquakes, trenches
225 million years ago
65 million years ago
135 million years ago
Present
Fig. 4-5, p. 88
Continental Movement
Climate Change
Climate Change and Natural
Selection
 Changes
in climate throughout the earth’s
history have shifted where plants and animals
can live.
Figure 4-6
Catastrophic events
 Asteroid
impacts
 Super Volcanoes
 These
affect biodiversity locally and on a
world-wide scale
Speciation - formation of a
new species
 Two

Phases
1. Geographic isolation
A
population is removed from others of it’s
species for a long period of time

2. Reproductive isolation
 The
removed population becomes so
genetically different over time that it can no
longer interbreed with others of it’s species
Measurements of Biodiversity
 Species
diversity – the number of different
species in a community
 Species
evenness – the abundance of
species in a community
Richness and Sustainability
 Higher
species richness = higher
productivity = higher sustainability
 Reasons:


More likely to withstand droughts, disease,
climate change, nutrient shortages
Higher number of producers lead to a
higher biomass which leads to more carbon
and nitrogen cycling
Extinction – the loss of a
species
 Background
extinctions
extinction – low rate of
 Mass
extinction-high rate of extinctions
due to specific cause

Climate change
Three types of extinctions



Local: A species is no longer found in an
area it once inhabited but is still found
elsewhere in the world.
Ecological: Occurs when so few members
of a species are left they no longer play its
ecological role.
Global (biological): Species is no longer
found on the earth.
Global Extinction
 Some
animals have become prematurely
extinct because of human activities.
Figure 11-2
Steps to extinction
Background extinctions:
1.
2.
3.
4.
Rare
Threatened
Endangered
Extinct
Endangered and Threatened
Species: Ecological Smoke Alarms
 Endangered
species: so few individual survivors that
it could soon become extinct.
 Threatened species: still abundant in its natural
range but is likely to become endangered in the
near future.
Figure 11-3
Red lists
 ICUN
– International Union for the
Conservation of Nature and Natural
Resources
 Published
list of threatened species
 www. iucnredlist.org
Some species are more prone
to extinction:
 K-strategists
 Specialists
 Tertiary
consumers
 Fixed migratory patterns
 Narrow distribution
 Commercially valuable
 Large territories
Grizzly bear
Utah prairie dog
Kirkland’s
warbler
Knowlton
cactus
Florida
manatee
Swallowtail
butterfly
Humpback
chub
Golden lion
tamarin
African elephant
Siberian tiger
Fig. 11-3, p. 224
Giant panda Black-footed Whooping
crane
ferret
Mountain gorilla Florida
panther
California
condor
Northern
spotted owl
Hawksbill
sea turtle
Blue whale
Black
rhinoceros
Fig. 11-3, p. 224
Indian Tiger
Range 100 years ago
Range today
(about 2,300 left)
Fig. 11-8a, p. 230
Black Rhino
Range in 1700
Range today
(about 3,600 left)
Fig. 11-8b, p. 230
African Elephant
Probable range 1600
Range today
Fig. 11-8c, p. 230
Asian or Indian Elephant
Former range
Range today
(34,000–54,000 left)
Fig. 11-8d, p. 230
Extinction Rate
 The
percentage of species that go extinct
within a certain time period
 The
current extinction rate is increasing at
an alarming rate due to human activities
Endangered Species
History of Extinctions

Extinctions have existed long before humans had
an influence

The current extinction crisis is the first to be caused
by a single species- US!
. This is happening faster than ever; a few
decades versus thousands to millions of years.

Humans are eliminating not only the species but,
the environment. Ex. Tropical rainforest
Effects of Humans on
Biodiversity
 The
scientific consensus is that human activities are
decreasing the earth’s biodiversity.
Figure 4-13
Human Caused Extinction
 Causes
 HIPPO
include:
C
 Habitat
Destruction
 Invasive species
 Population Growth
 Pollution
 Over-harvesting
 Climate Change
Cenozoic
Era
Period
Millions of
years ago
Quaternary
Today
Tertiary
65
Mesozoic
Cretaceous
Jurassic
180
Triassic
Species and families
experiencing
mass extinction
Extinction Current extinction crisis caused
by human activities. Many species
are expected to become extinct
Extinction within the next 50–100 years.
Cretaceous: up to 80% of ruling
reptiles (dinosaurs); many marine
species including many
foraminiferans and mollusks.
Extinction
Triassic: 35% of animal families,
including many reptiles and marine
mollusks.
Bar width represents relative
number of living species
250
Extinction
345
Extinction
Permian
Paleozoic
Carboniferous
Devonian
Permian: 90% of animal families,
including over 95% of marine
species; many trees, amphibians,
most bryozoans and brachiopods,
all trilobites.
Devonian: 30% of animal
families, including agnathan and
placoderm fishes and many
trilobites.
Silurian
Ordovician
Cambrian
500
Extinction
Ordovician: 50% of animal
families, including many
trilobites.
Fig. 4-12, p. 93
Natural Extinctions
 Causes



include
Climate change
Change in ecosystem
Lack of adaptations to change
How do extinctions affect us?
 Use
value lost – medicinal use, recreation,
crops, lumber
 Economic value – ecotourism (African
safari)
 Genetic information – genetic diversity
lost
 Non-use values – appreciation
Case Study:
The U.S. Endangered Species Act
 Biodiversity
hotspots in relation to the
largest concentrations of rare and
potentially endangered species in Figure
the U.S.
11-18