Transcript Describe

Ch. 10 - Biodiversity
Sect. 1 Objectives
• Describe the diversity of species types on
Earth, relating the difference between
known numbers and estimated numbers.
• List and describe three levels of
biodiversity.
• Explain four ways in which biodiversity is
important to ecosystems and humans.
• Analyze the potential value of a single
species.
Biodiversity(biological diversity) – the number of
different species in a given area
• Plants
– Trees, shrubs, flowers, weeds
• Animals
– Mammals, insects, fish, crustaceans
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Fungus
Insects
Bacteria
Etc.
How many are there?
• 1.7 million species are known
– Most are insects
• 10 million species are estimated to exist
Levels of Diversity
• Species diversity – number of different
species in an area
• Ecosystem diversity – variety of habitats,
communities
• Genetic diversity –
number of genes
contained in all
members of a
population
What makes everything
different?
• Genes (DNA) – code for different traits or
characteristics that can be inherited
– Everyone's is different (unless you are an
identical twin)
Why is Biodiversity Important?
• All species are dependant on other
species and are depended on by others
• Everyone fits in the food web/chain
• If you remove
one link, all the
others will fall
Keystone species – a species that is
critical to the functioning of the ecosystem
because it affects the survival and abundance of
many other species
• – one species that many others depend on
Ex: Sea Otters
• 1. Otters killed for fur
• 2. Sea urchin population grew
• 3. Kelp disapeared
Ex: Prairie dogs
Biodiversity and Survival
• More genetic diversity
means the population
has a greater chance of
surviving environmental
changes. (ie: global
warming)
• Ex: Hemophilia
Biodiversity and Humans
• More organisms the more things for us
– Food
– Antibiotics
– Clothing
– Shelter
– Chemicals
Ecotourism – tourism that supports the
conservation and sustainable development of
ecologically unique areas
• Has become very popular lately
Sect. 2 Objectives
• Define and give examples of endangered and
threatened species.
• Describe several ways that species are being
threatened with extinction globally.
• Explain which types of threats are having the
largest impact on biodiversity.
• List areas of the world that have high levels of
biodiversity and many threats to species.
• Compare the amount of biodiversity in the
United States to that of the rest of the world.
All species are considered one of
these: depending on their natural
numbers
• Extant
• Threatened
• Endangered
• Extinct
Extant – living animals
Threatened –
still abundant in its natural habitat but is
likely to become endangered because
of their declining numbers
Endangered – so few individuals
that they are likely to become
extinct
Extinct – no known individuals still
alive
Species most at risk
• Animals that are more likely to become
extinct are those that:
– Have small populations
– Migrate
– Need large or special habitats
– Are exploited by humans
• Currently humans are the greatest cause
of extinctions!
Species can be threatened by
• Humans
– Hunting
– Loss of habitat (75% of
current extinctions)
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Deforestation
Damming
Burning
Growing cities
Pollution
– Poaching
– Invasive species
• Natural Causes
– Interbreeding
– Natural Disaster
– Disease
Exotic – not native to an area
• When brought to a new area exotic
species can cause the extinction of other
species they out compete
• Ex: Fire Ant
– Horny Toads (Desert Horned Lizard) eat ants
– Fire ants (exotic species) kill horny toads.
– Horny toads are now threatened!
Generalist Species
• Species with a broad niche, can survive in
many different places
HUMANS
Often are invasive
species
Specialist Species
Species with a narrow niche. Only live in a
small range of environmental factors
Fewer if these
because they
can become
extinct more
readily
Critical Areas
• Tropical Rain Forests – over half the
worlds species live here
– Most species have not been named, yet
– But, lots of these are disappearing
• Due to habitat destruction by humans!
• Coral Reefs and Coastal areas
• Islands – why?
Biodiversity Hotspots – high number
of endemic species but are threatened by humans
Madagascar
• Biodiversity Hotspot
– Endemic Species
• 80% of plants
• 91% of reptiles
• 100% of lemurs (10% of worlds primate
population)
• Only 18% of the original forests remain!!
Sect. 3 Objectives
• List and describe four types of efforts to save
individual species.
• Explain the advantages of protecting entire
ecosystems rather than individual species.
• Describe the main provisions of the
Endangered Species Act.
• Discuss ways in which efforts to protect
endangered species can lead to controversy.
• Describe three examples of worldwide
cooperative efforts to prevent extinctions.
Ch. 10 Ecolog
• Read in your book, in Sect. 3, about the
following ways to save species. In your
Ecolog write a brief description of each!
– Captive-Breeding programs
– Preserving Genetic Material
– Zoos, etc.
– Conservation Strategies
• Write a paragraph about why it is
important to save species and the
biodiversity around the world.