Transcript CHAPTER 42 Earth`s Ecosystems and the Biosphere

p. 728-740 or Chap. 42
Earth’s Ecosystems and the Biosphere
1. Temperature and water -major climatic factors
determining the distribution of organisms...
2. Climate -the prevailing weather conditions in an area.
• Weather -short term
• climate –avg. over long term (year/season).
• Both are mainly temperature, water, light, and wind.
3. Climate and biomes.
• Climate determines makeup of biomes, the main
types of organisms living in an area.
Mean
temperature
and rainfall
are correlated
with the
biomes.
Factors Influencing Climate Patterns:
1. Largely determined by sunlight and the planet’s
movement in space (affects the season).
• The sun’s effect on the atmosphere, land, & water
establishes the temperature variations, cycles of air
movement, & evaporation of water … responsible
for latitudinal variations in climate.
2. Also determined by latitude, air currents, ocean
currents, the presence of bodies of water, mountains
and continents.
• Latitude -degrees north or south of equator.
• Mountains & continents change air & ocean
currents.
Link to Animation1 & 2
• The angle of the Earth’s axis is responsible for seasonal
variations on the Earth.
Review of Air Circulation
• The tropics experience the greatest input and least
seasonal variation in solar energy of any region.
• Solar energy especially near the equator initiates a
global circulation of air, creating precipitation and
winds.
• Local and seasonal effects on climate.
• Bodies of water (oceans) and topographic features such
as mountain ranges can affect local climates.
• Mountains affect temperature & rainfall greatly.
• This creates prevailing air currents.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Four Resources Required by Life
(these resources are not evenly distributed)
1. Chemical nutrients to feed and build cells.
2. Energy to power the building of cells.
•
light for plants & photosynthetic organisms.
•
food for animals & decomposers.
3. Water(l) to serve as a medium for metabolism.
4. Appropriate temperatures.
Earth’s Biomes
• Biomes –land/sea areas w/ similar env/similar
communities of vegetation.
• Plants dominate all land communities and define
their biome. Which plants … determine which
animals live in the biome.
• Land biomes: desert, grassland, tropical rain
forest, taiga (tĪ-guh), tundra, temp. rain forest, etc.
(bold we will cover)
• Aquatic biomes: open ocean, coral reefs, deep
sea vents, rivers, etc.
Student Presentations on Earth’s Biomes
1. Name the biome
2. Provide its characteristics, what defines it
3. Discuss if the vegetation is lush or sparse,
whether diversity of life is great or small
4. Name the major plants and animals (if more than
3 each, just say and many others)
5. Describe some plant and animal adaptations to
living in the biome
6. If there is something special, provide it.
Deserts
• -low rainfall (< 10 inches/yr), often but not always hot.
• Vegetation -usually sparse, includes cacti and succulents.
Also horned lizards, snakes, kangaroo rat, bighorn sheep,
burrowing owl.
• Plant Adaptations:
shallow roots to quickly
absorb H20, waxy coat
to prevent water loss
• Animal Adaptations:
many nocturnal, avoid
the heat/water loss.
How are snakes adapted to living in the
desert?
Grasslands
• Fertile soils … decomposition of grass over eons. U.S.A.
grasslands converted into farmland, the breadbasket of
America. Only ~1% of the USA grasslands exist.
Adaptations:
• Plant germination/growth in
the moist spring/fall, dies in
dry summer. Too dry for
anything but grasses. Plants
able to survive fire (roots).
• Herbivores must live off dry
grass or seeds in summer.
Prairie dogs, bison, hawks.
Tropical Rain Forests
• Near equator, lots of rain, temp. hardly varies, great variety of
life forms. Highest biodiversity on the planet! (Number of types
of organisms/area.)
Adaptations:
• Organisms tend to fly or dwell in trees.
• When decomposers
release nutrients, plants
quickly absorb them.
• The soil is infertile from
this & the rain, why
turning it into farmland
is very risky.
Taiga (Northern Coniferous Forest)
• Taiga (tĪ-guh) -largest terrestrial biome on Earth. Long
cold winters and short wet summers.
• Conifers are adapted to the short growing season,
evergreen leaves never drop, ready to go at start. Also
waxy coat & small needle size to prevent water loss.
• Low biodiversity.
• Conifer forests
home to various
animals, some of
which adapt by
hibernating.
Tundra
• Very short growing season. The climate is windy and cold.
A layer of permafrost (ground that does not thaw) found
below ~1.5 feet, preventing root growth.
• Plant adaptations:
Low growing plants and shallow roots to avoid wind and
permafrost (dwarf willow, dwarf clover).
• Animals adapted to the cold (caribou, lemmings, and artic
foxes).
• Two types of tundra, arctic, found around the Arctic circle,
and alpine, found on very high mountaintops.
The Open Ocean
Includes most of the world’s water & most of the Earth!
• Is the desert of the oceans, very
little primary production.
• Plankton (the producers)
adapted to live only at the top
(light) and deplete the water’s
nutrients.
• A great variety of fish,
mammals & zooplankton
(consumers).
Coral Reefs
• Dominated by coral and
include a very diverse and
rich assortment of
organisms.
• Very high biodiversity
(number of types of
organisms/area) & primary
production.
• Extremely sensitive to
disturbance.
Deep Sea Vents (hydrothermal vents)
• Only biome not dependent on the
sun! Energy comes from the magma
heating water that dissolves sulfur.
• Chemosynthetic bacteria obtain
energy from hydrogen sulfide to
build sugar. Most bacteria adapted
to live in nearly boiling water!
• All consumers (white clams,
mussels, blind crabs, tube worms,
fish) depend on chemosynthetic
bacteria.
• There are other fresh & salt water biomes.
• How are fish and ducks adapted to live in a
water biome?
• What relationship exists between predatory
fish and a baby duck?
• Next lesson: Ecosystems (p717-728 or ch 41)