Transcript Ecosystems and their Components

Ecosystems and their
Components
Chapter 3
Ecosystem Components
The Earth is divided into four
components that all interact
together.
atmosphere (air)
hydrosphere (water)
geosphere (rock, soil and
sediment)
biosphere (living things)
www.sws.uiuc.edu/nitro/biggraph.asp
Atmosphere
thin layer of gases surrounding earths surface.
layers of the atmosphere include:
troposphere
extends 11 miles above sea level at
equator and 4 miles above sea level at
poles.
contains all air we breathe, including
nitrogen (78%), oxygen (21%), and
greenhouse gases (natural greenhouse
effect)
where all weather occurs
stratosphere
next layer, extends 11-31 miles above
earth’s surface
contains ozone to help filter out UV
radiation (98%); “global sunscreen”
all water at or
near the earth’s
surface
founds as water
vapor, liquid
water, ice and
frozen in
permafrost
97% of the earths
water is found in
the ocean (cover
71% of earth’s
surface)
Hydrosphere
Layers of soil, rock and
sediment at the earths
surface and in layers below.
core: hot, molten inner
layer, mostly iron
mantle: thick rock middle
layer made of silicon, iron,
oxygen and magnesium
crust: outermost layer,
contains all nonrenewable
fossil fuels and minerals,
as well as renewable soil
nutrients and organisms
Geosphere
Biosphere
Parts of atmosphere,
hydrosphere and
geosphere where all
living components are
found
Ecology: study of
interactions between
organisms and their
environment
biotic and abiotic
components
Energy in Ecosystems
Ecosystems are driven by
1. interactions between organisms
2. the flow of high-quality energy (sun)
most energy is absorbed or reflected back into
space by the atmosphere
goes to generating winds (1%)
plants, algae and bacteria use to produce
nutrients (.1%)
natural greenhouse effect (warms earth to
sustain life)
3. cycling of nutrients
Within an Ecosystem...
Interactions happen
between organisms,
populations, and
communities
includes both biotic
and abiotic
components
all organisms
organized into trophic
levels depending on
source of food or
nutrients
Producers
Trophic levels and feeding
relationships
autotrophs. use photosynthesis (water + carbon dioxide + light ---> oxygen
and glucose)
includes plants, algae, phytoplankton and some bacteria (chemosynthesis)
Consumers
heterotrophs. obtain energy by feeding on other organisms.
primary consumers, secondary consumers, tertiary consumers.
herbivores, omnivores and carnivores.
Decomposers
consumers that release nutrients from the wastes of plants and animals and
return those nutrients to the soil, air or water for reuse.
mostly bacteria and fungi.
detritivores: feed on the wastes and dead bodies of other organisms and
break into smaller particles (detritus)
earthworms and insects; vultures (scavengers)
Cellular Respiration
producers, consumers, and decomposers within their
cells use chemical energy to fuel their life processes
aerobic respiration
glucose + oxygen ---> carbon dioxide + water +
energy
opposite of photosynthesis
anaerobic respiration
occurs in the absence of oxygen (fermentation)
end products include methane, ethyl alcohol,
acetic acid or hydrogen sulfide
Energy Cycling
Illustrated through food
chains and food webs
describes the flow of
energy from one trophic
level to another
photosynthesis,
feeding, and
decomposition
some energy lost to
the environment as
heat through these
processes
biomass: weight of all organic matter contain it its organisms
chemical energy in biomass is transferred from one
trophic level to another
energy is lost with each transfer, less is available to the
next trophic level
general rule is only 10% of available energy is passed
between trophic levels, the rest is lost (ecological
efficiency)
explains why there are rarely more than 4-5 trophic
levels (not enough energy to support), and why more
organisms are found in lower trophic levels (fewer top
carnivores)
biomass found in each ecosystem is determined by how much
solar energy the producers can capture and store.
varies greatly depending on the ecosystem
gross primary productivity (GPP): rate at which an
ecosystem’s producers convert solar energy into chemical
energy; total amount of energy captured by producers
net primary productivity (NPP): rate at which producers use
photosynthesis to produce and store chemical energy minus
the rate at which they use some of this stored chemical
energy through aerobic respiration
this ultimately limits the number of consumers that can
survive on earth
more productivity = more organisms supported
highest in estuaries and rainforests
Cycling of Matter in
Ecosystems
the elements and compounds that make up
nutrients move continually through air,
water, soil, rock, and living organisms.
This is illustrated through five
biogeochemical (nutrient cycles)
water, carbon, phosphorus, nitrogen and
sulfur cycles.
Importance of
Ecosystems