Transcript ecossytem ppt 1 - Bioenviroclasswiki

Chapter 3
Ecosystems: What Are
They and How Do They
Work?
Chapter Overview Questions
• What is ecology?
• What basic processes keep us and other
organisms alive?
• What are the major components of an
ecosystem?
• What happens to energy in an ecosystem?
• What are soils and how are they formed?
• What happens to matter in an ecosystem?
• How do scientists study ecosystems?
Core Case Study:
Have You Thanked the Insects
Today?
• Many plant species depend on insects for
pollination.
• Insect can control other pest insects by
eating them
Figure 3-1
Core Case Study:
Have You Thanked the Insects
Today?
• …if all insects disappeared, humanity
probably could not last more than a few
months [E.O. Wilson, Biodiversity expert].
– Insect’s role in nature is part of the larger
biological community in which they live.
THE NATURE OF ECOLOGY
• Ecology is a study
of connections in
nature.
– How organisms
interact with one
another and with
their nonliving
environment.
Figure 3-2
Universe
Galaxies
Solar systems
Biosphere
Planets
Earth
Biosphere
Ecosystems
Ecosystems
Communities
Populations
Realm of ecology
Organisms
Organ systems
Communities
Organs
Tissues
Cells
Populations
Protoplasm
Molecules
Atoms
Organisms
Subatomic Particles
Fig. 3-2, p. 51
Organisms and Species
• Organisms, the different forms of life on
earth, can be classified into different species
based on certain characteristics.
Figure 3-3
Other animals
281,000
Known species
1,412,000
Insects
751,000
Fungi
69,000
Prokaryotes
4,800
Plants
248,400
Protists
57,700
Fig. 3-3, p. 52
Case Study:
Which Species Run the World?
• Multitudes of tiny microbes such as
bacteria, protozoa, fungi, and yeast help
keep us alive.
– Harmful microbes are the minority.
– Soil bacteria convert nitrogen gas to a usable
form for plants.
– They help produce foods (bread, cheese,
yogurt, beer, wine).
– 90% of all living mass.
– Helps purify water, provide oxygen,
breakdown waste.
– Lives beneficially in your body (intestines,
Populations
• A population is a
group of interacting
individuals of the
same species
occupying a specific
area.
– The space an
individual or
population normally
occupies is its
habitat.
Figure 3-4
Populations
• Genetic diversity
– In most natural
populations
individuals vary
slightly in their
genetic makeup.
Figure 3-5
THE EARTH’S LIFE SUPPORT
SYSTEMS
• The biosphere
consists of several
physical layers that
contain:
– Air
– Water
– Soil
– Minerals
– Life
Figure 3-6
Biosphere
• Atmosphere
– Membrane of air around the planet.
• Stratosphere
– Lower portion contains ozone to filter out most
of the sun’s harmful UV radiation.
• Hydrosphere
– All the earth’s water: liquid, ice, water vapor
• Lithosphere
– The earth’s crust and upper mantle.
What Sustains Life on Earth?
• Solar energy,
the cycling of
matter, and
gravity sustain
the earth’s life.
Figure 3-7
What Happens to Solar Energy
Reaching the Earth?
• Solar energy
flowing through
the biosphere
warms the
atmosphere,
evaporates and
recycles water,
generates winds
and supports
plant growth.
Figure 3-8
Animation: Sun to Earth
PLAY
ANIMATION
ECOSYSTEM COMPONENTS
• Life exists on land systems called biomes
and in freshwater and ocean aquatic life
zones.
Figure 3-9
Average annual precipitation
100–125 cm (40–50 in.)
75–100 cm (30–40 in.)
50–75 cm (20–30 in.)
25–50 cm (10–20 in.)
below 25 cm (0–10 in.)
4,600 m (15,000 ft.)
3,000 m (10,000 ft.)
1,500 m (5,000 ft.)
Coastal
mountain
ranges
Sierra
Nevada
Mountains
Great
American
Desert
Coastal chaparral Coniferous
and scrub
forest
Rocky
Mountains
Desert
Great
Plains
Coniferous
forest
Mississippi
River Valley
Prairie
grassland
Appalachian
Mountains
Deciduous
forest
Fig. 3-9, p. 56
Nonliving and Living
Components of Ecosystems
• Ecosystems consist of nonliving (abiotic)
and living (biotic) components.
Figure 3-10
Animation: Roles of Organisms
in an Ecosystem
PLAY
ANIMATION
•
Factors That Limit Population
Growth
Availability of matter and energy resources
can limit the number of organisms in a
population.
Figure 3-11
Factors That Limit Population
Growth
• The physical
conditions of
the
environment
can limit the
distribution of a
species.
Figure 3-12
Producers: Basic Source of All
Food
• Most producers capture sunlight to
produce carbohydrates by photosynthesis:
Producers: Basic Source of All
Food
• Chemosynthesis:
– Some organisms such
as deep ocean bacteria
draw energy from
hydrothermal vents
and produce carbohydrates
from hydrogen sulfide (H2S)
gas .
Consumers: Eating and Recycling
to Survive
• Consumers (heterotrophs) get their food
by eating or breaking down all or parts of
other organisms or their remains.
– Herbivores
• Primary consumers that eat producers
– Carnivores
• Secondary consumers eat primary consumers
• Third and higher level consumers: carnivores that
eat carnivores.
– Omnivores
• Feed on both plant and animals.
Decomposers and Detrivores
– Decomposers: Recycle nutrients in ecosystems.
– Detrivores: Insects or other scavengers that feed
on wastes or dead bodies.
Figure 3-13
Two Secrets of Survival: Energy
Flow and Matter Recycle
• An ecosystem
survives by a
combination of
energy flow and
matter recycling.
Figure 3-14
Animation: Matter Recycling
and Energy Flow
PLAY
ANIMATION
BIODIVERSITY
Figure 3-15
Biodiversity Loss and Species
Extinction: Remember HIPPO
• H for habitat destruction and
degradation
• I for invasive species
• P for pollution
• P for human population growth
• O for overexploitation
Why Should We Care About
Biodiversity?
• Biodiversity provides us with:
– Natural Resources (food water, wood, energy,
and medicines)
– Natural Services (air and water purification,
soil fertility, waste disposal, pest control)
– Aesthetic pleasure
Solutions
• Goals, strategies
and tactics for
protecting
biodiversity.
Figure 3-16
ENERGY FLOW IN
ECOSYSTEMS
• Food chains and webs show how eaters, the
eaten, and the decomposed are connected to
one another in an ecosystem.
Figure 3-17
Food
Webs
• Trophic levels are
interconnected
within a more
complicated food
web.
Figure 3-18
Animation: Rainforest Food
Web
PLAY
ANIMATION
Energy Flow in an Ecosystem:
Losing Energy in Food Chains
and Webs
• In accordance with the 2nd law of
thermodynamics, there is a decrease in
the amount of energy available to each
succeeding organism in a food chain or
web.
Energy Flow in an Ecosystem:
Losing Energy in Food Chains
and Webs
• Ecological
efficiency:
percentage of
useable energy
transferred as
biomass from
one trophic level
to the next.
Figure 3-19
Animation: Energy Flow in Silver
Springs
PLAY
ANIMATION
Productivity of Producers:
The Rate Is Crucial
• Gross primary
production
(GPP)
– Rate at which
an ecosystem’s
producers
convert solar
energy into
chemical
energy as
biomass. Figure 3-20
Net Primary Production (NPP)
• NPP = GPP – R
– Rate at which
producers use
photosynthesis to
store energy minus
the rate at which they
use some of this
energy through
respiration (R).
Figure 3-21
• What are nature’s three most productive and
three least productive systems?
Figure 3-22
SOIL: A RENEWABLE
RESOURCE
• Soil is a slowly renewed resource that
provides most of the nutrients needed for
plant growth and also helps purify water.
– Soil formation begins when bedrock is broken
down by physical, chemical and biological
processes called weathering.
• Mature soils, or soils that have developed
over a long time are arranged in a series of
horizontal layers called soil horizons.
SOIL: A RENEWABLE
RESOURCE
Figure 3-23
Layers in Mature Soils
• Infiltration: the downward movement of
water through soil.
• Leaching: dissolving of minerals and
organic matter in upper layers carrying
them to lower layers.
• The soil type determines the degree of
infiltration and leaching.
Some Soil Properties
• Soils vary in the
size of the particles
they contain, the
amount of space
between these
particles, and how
rapidly water flows
through them.
Figure 3-25
Soil Profiles of the
Principal
Terrestrial Soil
Types
Figure 3-24
Mosaic of
closely
packed
pebbles,
boulders
Weak humusmineral mixture
Desert Soil
(hot, dry climate)
Dry, brown to
reddish-brown
with variable
accumulations
of clay, calcium
and carbonate,
and soluble
salts
Alkaline,
dark,
and rich
in humus
Clay,
calcium
compounds
Grassland Soil
(semiarid climate)
Fig. 3-24a, p. 69
Acidic
light-colored
humus
Iron and
aluminum
compounds
mixed with
clay
Tropical Rain Forest Soil
(humid, tropical climate)
Fig. 3-24b, p. 69
Forest litter leaf
mold
Humus-mineral
mixture
Light, grayishbrown, silt loam
Dark brown
firm clay
Deciduous Forest Soil
(humid, mild climate)
Fig. 3-24b, p. 69
Acid litter
and humus
Light-colored
and acidic
Humus and
iron and
aluminum
compounds
Coniferous Forest Soil
(humid, cold climate)
Fig. 3-24b, p. 69