Download Chapter 3 Ecosystems Notes 1

Ecology
Is the study of the interactions
of living organisms with one
another and their physical
environment (soil, water,
weather, shelter).
Ecosystems
Ecosystems are complex, interactive
systems that include both living (biotic)
and non-living (abiotic) components of the
environment. Populations of organisms
are dependent on their interactions with
both the biotic and abiotic factors that
make up the environment. All the
different ecosystems on Earth make up the
Biosphere.
Ecosystems
Ecosystems have a structure that groups the
organisms in an order of least to most complex.
1. Individual organisms (species=organisms
interbreed an produce fertile offspring)
2. Populations- 2 or more species living together
3. Communities- 2 or more populations living
together
4. Ecosystems- community with all physical
aspects of its habitat
5. Biosphere- All the different ecosystems joined
Ecosystems
Populations are species that live an interact in
a particular area. There are several ways to measure
the numbers of species in a population:
1. Density dependent factors- these are limiting
factors that affect large population more than small
ones. They include competition (for food, water,
shelter, and space), predation, parasitism, and
disease. The larger the population the more these
factors affect the numbers and health of the
population.
Ecosystems
2. Density independent factors- are factors that
occur regardless of how large or small the
population. They are mostly abiotic; weather
changes, natural pollution, natural disasters.
3. Abiotic and Biotic factors- affect population size
and balance
abiotic- water, shelter, oxygen, food, temperature,
amount of sunlight, and precipitation.
biotic- bacteria, fungi, plants, and animals.
Ecosystems
Carrying Capacity- Is the
largest population of organisms
that an area can support with
food, water, and shelter.
Ecosystems
The interactions of more than one
population form communities (all the
organisms that live in a given area and
the abiotic factors such as water, soil, air,
and climate) and several communities
interaction with each other form
ecosystems, and all the ecosystems on
Earth form the Biosphere.
Ecosystems
Organisms in an ecosystem constantly interact with
each other an these actions tend to
1. Generate stability within the ecosystem
2. Facilitate growth or restrain growth
3. Maintain the balance of resources and who uses
or consumes them
4. Change both the abiotic and biotic characteristics
of the environment
Symbiosis
Symbiosis means two or more species
live together in a close long term
association. Cooperation is the
hallmark relationship seen in any
symbiotic relationship. There are three
types of symbiotic relationshipsparasitism, mutualism, and
commensalism.
Predation
Predation is the interaction
between predator and prey. When
prey is plentiful the population of
the predator increases and when
prey is small the predator
population decreases. There is a
constant balancing of prey and
predator.
Competition
Competition is the relationship that
occurs when two or more organisms
need the same resources at the same
time. Competition usually results in a
decrease in population of the organism
less adapted to compete for a particular
resource.
Commensalism
Commensalism is the
interaction between two species
where one benefits from the
association and the other is
neither benefitted or harmed.
Parasitism
Parasitism is a relationship where one
organism benefits at the expense of the
other organism. Examples are tape worms,
bacteria, ticks, fleas, mistletoe. Parasitism
must be kept in balance or the parasite
puts its own existence in jeopardy if it
overly weakens its host.
The organism that a parasite lives on or in
is
called a host.
Mutualism
Mutualism is the relationship
where both organism benefit.
Example bacteria in our intestinal
tract, bird on cows back, bird in
crocodile's mouth. Working
together they both have a better
opportunity to survive.
The ultimate source for all
energy on earth with the
exception of hydrothermal
vents (chemosynthesis) is the
sun through photosynthesis.
6CO2 + 6H2O + sunlight =
C6H12O6 + 6O2
Food Chain
A food chain is a diagram that shows
how energy flows from one organism
to the next. Usually no more than 4
tropic levels because the energy runs
out, (producers, primary consumers,
secondary consumers, tertiary
consumers, and decomposers at each
level). Can be either terrestrial or
aquatic or a combination of both.
Food Chain
The arrows show energy flow; arrows always
flow from the lowest level to the higher
level. What is eaten → to who eats it.
snake
↑
rat
↑
wheat
Energy Levels
Autotroph- obtains its energy from
sunlight through the process of
photosynthesis.
Heterotroph- Cannot make its own
energy. Must eat something to obtain
energy.
Detritivores- obtains their energy from
eating dead organisms and returning
nutrients to the soil.
Food Chain Bottom
At the very bottom of the food chain are the
producers. They include plant, algae, and
phytoplankton. They use sunlight to make their own
energy through photosynthesis (autotrophs). They
in turn are eaten by other organisms for food energy
(heterotrophs). The matter is transferred from one
organism to the next repeatedly and finally back to
the physical environment. Total matter remains
constant, cannot create or destroy matter
but can change its form and location.
Producers
Producers make their own energy
through photosynthesis. All other
organisms depend on the
producers in one way or another
for energy. They are on the lowest
trophic level of any ecosystem ( grass,
herbs, algae, phytoplankton, trees, and shrubs).
Primary Consumers
Primary consumers eat
producers. They are organisms
of the second trophic level.
They are often called herbivores
( cows, mice, horses, caterpillars).
Secondary Consumers
Secondary consumers are meat
eaters and are often called
carnivores. They are organisms of
the third trophic level. Some
secondary consumers are
omnivores because they eat both
meat and plants (raccoons, snakes,
wolves, tigers, seals).
Tertiary Consumers
These are the top consumers.
They are carnivores that eat
other carnivores. Because they
require so much energy there
are very few of these organisms
in an ecosystem (humans, hawks, bears,
lions, osprey, killer whales)
Detritivores/Decomposers
This a special class of consumers
that break down dead organisms
or material and recycle it into
the ground to become nutrients
for future producers ( vultures,
bacteria, fungi, worms).
Food
Web
Food web is a diagram that shows the
feeding relationships in an ecosystem.
Arrows in a food web point in the
direction showing where the energy
flows to (organism eaten starts the arrow
and the eater ends the arrow).
Two food webs: Terrestrial and Aquatic
Humans are the top consumers in both
Food Web
Energy Pyramids
Energy pyramids show how energy
flows from one trophic level to the
next trophic level. There are normally
no more than 4 trophic levels because
the energy runs out. Decomposers at
each level are responsible for
recycling the dead materials back in
to the soil.
Energy Transfer
Only 10% of the energy transfers
from one trophic level to the next.
90% is lost due to heat
requirements of metabolism of the
organism in that trophic level. This is
why there are so few trophic levels in
nature;
The energy runs out.
Energy Pyramids
Energy Trophic Levels
st
1
Producers- Make energy through
Photosynthesis
2nd Primary Consumers- Herbivores
rd
3 Secondary ConsumersCarnivores
4th Tertiary Consumers- Omnivores
Pyramid Types
Energy Pyramid- shows the transfer of
energy through trophic levels.
Number Pyramid- the bottom is the
number of producers for this trophic level
and counts the number of organisms in
each trophic level. Numbers of organism
decrease up the pyramid.
Biomass Pyramid- the biomass of all
organisms at different trophic levels
Types of Communities
Marine or Aquatic- shallow
ocean, open ocean, deep
ocean
Fresh water- swamps, lakes,
bogs, rivers
Terrestrial- seven different
types
Aquatic Communities
Shallow Ocean- Most of the ocean
creature can be found here. Sunlit
waters usually no more than 300
meters deep. Filled with sea
creature and plants. Plankton
floats freely on the surface.
Aquatic Communities
Open Ocean- generally begins at
the start of the continental slope.
Water temperature and sunlight
decrease really fast. Giant Sea
Urchins, Whales, and Sharks.
Plankton floats freely on the
surface.
Aquatic Communities
Deep Ocean- Extreme pressures,
very low temperature, and no
sunlight. The life that exist here
are normally found around
hydrothermal vents and get their
energy through Chemosynthesis.
Terrestrial Communities
1. Tropical Rain Forest- 80”-180”
rain per year. Large variety of species,
probably ½ of all Earth’s species live
here. Rather infertile soil (rain washes
most of the minerals away). Most of
the nutrients of the rain forest are in
the plants.
Terrestrial Communities
2. Savannas- Dry tropical
grasslands. 35”-60” of rain
per year. Widely sparse
trees. Large herds of grazing
animals and predators.
Terrestrial Communities
3. Deserts- Arid lands, less
than 10 “ of rain per year.
Vegetation very sparse.
Mostly found in Africa
(Sahara), Asia, and Australia.
Common plant is the cactus.
Terrestrial Communities
4. Temperate Grasslands- Seas
of Grass- Highly productive soil,
prairie land, deep grass roots to
hold the soil and absorb water.
Mostly North America, Central
Eurasia, and South America. Bison
or Buffalo
Terrestrial Communities
Temperate Deciduous ForestRich Hardwoods- Plenty of rain
30”-100” rain per year. Warm long
summers, and cold winters. Eastern
USA, Southeastern Canada, Europe,
and Western Asia. Animals are deer,
bear, squirrels, beavers. Beech,
Hickory, and Oak trees are plentiful.
Terrestrial Communities
6. Taiga Forest- Great Conifer
Forest of the North- Cold, wet, long
snowy winters . Most of rain in the
summer. Leached out soil. Lots of
marsh land, lakes, huge forest of
spruce and fir trees. Mostly Eurasia
and North America. Deer, elk, moose,
wolves, and bears are common.
Terrestrial Communities
7. Tundra- Cold Plains of the
Far North- Few trees and covers
20% of Earth’s surface. 10” of
rain or less per year. Water that
falls is usually frozen. Land is
boggy permafrost