Transcript Humans in the Biosphere

Humans in the Biosphere
Biodiversity

The variety of life in an area that is determined
by the number of different species in that area

Benefits
Increases stability of the ecosystem (more for food
chains!)
 Contributes to the health of the biosphere

3 types of Biodiversity
Genetic Diversity
 Species Diversity
 Ecosystem Diversity
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Genetic Diversity

The variety of genes or inheritable
characteristics that are present in a
population

Example: If a trait allows an insect to
survive a certain type of pesticide, it would
be beneficial for that insect to pass on that
trait that is found in its DNA

(survival of the fittest!)
Species Diversity
The number of different species and the
relative abundance of each species in a
biological community
 As you move from the polar regions to the
equator, species diversity increases
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Rainforests have the greatest amount of
species diversity
Ecosystem Diversity

The variety of ecosystems that are present
in the biosphere
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Remember the different ecosystems?
Different abiotic factors in each ecosystem
support different types of living things
 The Tundra is home to moose and wolves
while the Rainforest is home to exotic birds
and spider monkeys!
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So why is biodiversity important for us?

Economics

We’re able to cross different plants to get a new
better hybrid plant
 Teosinte
plant = genes that are resistant to viruses
 Corn = yummy food for us

Corn + Teosinte = Yummy food without viruses = more food!
So why is biodiversity important for us?
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Medicine

We use various plants for medicinal purposes!
 Quinine
plants for malaria
 Madagascar Periwinkle to treat Ovarian Cancer and
leukemias
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Has increased survival rates from 20% to more than 95%!!!
We’re still searching for more uses of plants and
animals that benefit humans
So why is biodiversity important for us?

How do other organisms supply humans?
Plants = Oxygen
 Tiny Plankton = food for small fish = food for us!
 Healthy Ecosystems can help to provide us with
clean drinking water
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We just have to keep them clean!
Threats to Biodiversity
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Review!
Extinction – a species is COMPLETELY gone!
 Endangered – a species is almost extinct!
 Threatened – a species is almost endangered!
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These things are not always humans fault,
however they have been recently!
Mass Extinctions

An event in which a large percentage of all
living species become extinct in a relatively
short period of time.

The last mass extinction occurred about 65
million years ago – remember the dinosaurs?
Causes of Extinction
Aside from natural disasters,
actions by humans such as:
 Habitat destruction
 Poaching
 Pollution and
 Introducing an exotic species
can cause extinction.
Estimated # of Extinctions Since 1600
Group
Main
land
Island Ocean
Total
Approximate # of
species
% of Group
Extinct
Mammals
30
51
4
85
4000
2.1
Birds
21
92
0
113 9000
1.3
Reptiles
1
20
0
21
6300
0.3
Amphibians
2
0
0
2
4200
0.05
Fish
22
1
0
23
19,100
0.1
Invertebrates
49
48
1
98
1,000,000+
0.01
Flowering
Plants
245 139 0
384 250,000
0.2
How do humans impact the Earth?
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Habitat Disruption

Deforestation – removal of trees and
destruction of forests
 Why
is this bad?
 Less trees = less species diversity, habitat loss,
disruption of carbon cycle
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Desertification – over-farming and overgrazing turn productive farm land into a desert
Erosion

Wearing away of surface soil by wind and
water
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Caused by humans removing too many
trees which serve as a buffer for erosion
Pollution
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Greenhouse Effect
A natural phenomenon where gases reflect
heat back toward the Earth, keeping it warm
 Caused by an accumulation of greenhouse
gases (such as CO2)
 CO2 is released by burning fossil fuels and
breathing!
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Effects of Greenhouse Gases

Greenhouse gases create a heat blanket
in the atmosphere increasing the Earth’s
temperature
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Most people believe this is causing Global
Warming!
Can be helped by planting more trees
which convert CO2 to O2 during
photosynthesis
Acid Rain
Nitric Oxides and Sulfur Dioxides
accumulate in the atmosphere and
contribute to precipitation being acidic
 Causes damage to plants and also manmade structures

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The Ozone Layer
Protects us from harmful UV Rays

Which cause sunburns (ouch!), eye damage,
and even cancer (yikes!)
Made of Ozone Molecules (O3)
 Destroyed by CFC’s (chloroflourocarbons)

Released from aerosol spray cans (banned in
the 1980s)
 Have caused a major hole in the ozone layer
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Resource Use
 Renewable
Resources - natural
resources that can be replaced
in a relatively short amount of
time (sun, wind, rain …)
Nonrenewable Resources - those
that either take a very long time
to replace or cannot be replaced
at all (coal and oil)
Global Warming
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An increase in Earth’s average
temperature

The Earth is getting warmer, however it
fluctuates between warm and cool periods
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Do your part to keep the Earth clean and
to decrease your carbon footprint!
How do you decrease your carbon
footprint?
Use renewable sources of energy
 Take quicker showers (water
conservations)
 Plant trees and shrubs
 Turn off the lights when you’re not in the
room
 Can you think of any others?
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