Download SHOW-4-2005

How do plants
affect the climate?
How do plants affect our climate?
1) Plants purify & replenish our air & water (e.g.
recycling CO2, O2 & soil/water nutrients)
2) Earth’s temperatures are influenced by plants
due to absorption of solar radiation (photosynthesis).
3) Plants increase humidity by absorbing water that is
way below ground level and releasing it (by
transpiration) to the atmosphere.
How do plants affect our climate?
4) Plants reduce flooding and desertification
(erosion).
5) Plants influence microclimates (climates in a
small area) by cooling, shading, etc.
How do plants affect our climate?
6) Plants can emit volatile organic molecules.
…affects
Precipitation
patterns
4) Plants influence the microclimate (climate of small area)
How do plants affect our climate?
7) Fires
Discussion Question #1:
Which biomes are the most popular
with people? Why?
Average
number of
plant species:
Biome:
Tropical Rainforest
3200
Savanna
1000
Chaparral
2300
Desert
1100
Temperate Grassland
1400
Temperate Deciduous
Forests
1900
Temperate Evergreen
Forests
1600
Taiga
800
Tundra
400
July, 2005
60oN
30oN
Equator
30oS
Rainforest
Desert
!Kung of Kalahari Desert
Sherenti of Amazon Forest
Average
number of
plant species:
Biome:
Tropical Rainforest
3200
Savanna
1000
Chaparral
2300
Desert
1100
Temperate Grassland
1400
Temperate Deciduous
Forests
1900
Temperate Evergreen
Forests
1600
Taiga
800
Tundra
400
July, 2005
What is the source of all
this biodiversity?
Discussion Question #2:
What basic assumption (or philosophy or
attitude) is at the core of scientific research?
Two Important Questions:
“ Did life on earth always
look the same as it does now? ”
“ What generated all the
diversity of life we currently
see on earth? ”
3 Basic Explanations for Earth’s Biodiversity:
No Evolution (Creationism)
Microevolution = relatively small
changes over time...that’s all
(Intelligent Design)
Macroevolution = speciation
(Charles Darwin et al. )
Charles Darwin
Theory of Natural Selection
Resources that organisms compete for:
• Energy
• Nutrients
• Water
• Proper Temperature
• Space to live
• Reproduction (a mate)
• Safety
Ecological Niche:
“how an organism attains and utilizes
the resources of the environment”
OR
“The job, or profession, of an organism”
A brief description of Natural Selection:
1) Organisms within a population contain numerous
natural variations for most characteristics
(Morphological, Biochemical, Behavioral)
2) This variation is genetic (heritable)
Fuchsia
Holly
Tomato
Potato
3) Individuals within any population will produce more
offspring than can survive on the resources available
to them. The offspring will compete with each other,
and with other species.
Darwin and his wife had 10 children (3 died)
4) Offspring that have genetic variations that are more
favorable in a certain environment will survive and
reproduce more than those that have less
favorable variations. The genetic makeup of the
population changes (evolves)…...
Microevolution (and eventually Macroevolution) occurs.
5) All of this variation is random. Also, changes in the
environment are chaotic. So, natural selection
yields exquisite adaptations that are quite independent
of any ‘design’ process.
3 relevant examples
We can see microevolution taking place:
1) The emergence of new strains of Influenza
viruses every winter.
2) Evolution of new strains of HIV (AIDS)
and Hepatitis viruses.
3) The advent of antibiotic-resistant strains
of bacteria (like for tuberculosis).
4) Insects and weedy-plant species that have
evolved the ability to resist chemical
treatments designed to kill them.
Artificial Selection
Age of the Earth….
Gideon Society says earth was created in 4004 BC...
Radioactivity dating says its 4.5 billion years old.…
If we can develop different kinds of animals and crops
in just a few thousand years, isn’t it hard to believe
that nothing would change over millions of years?