organisms in their environment - amazing world …...•organisms that cannot make their own source...
TRANSCRIPT
Organisms in their
Environment
Vocabulary
• An organism is a
living thing.
– E.g. a fish
Vocabulary
• A habitat is where
an organism lives
– E.g. a pond
Vocabulary
• A group of the same kind of organisms
living in the same habitat are called a
population.
Vocabulary
• All the populations of organisms together in
a habitat are called the community.
Vocabulary
• The habitat and the
community
together are called
the ecosystem.
Ecosystems
• A distinct, self-supporting system of
organisms interacting with each other and
with a physical environment..
The Composition of
Ecosystems
Components of Ecosystems
• Whatever the size, ecosystems usually
have the same components
– Producers
– Consumers
– Decomposers
– A physical environment
Producers
• Producers are green plants that “produce”
chemical energy from light energy.
• They do this by a process called
photosynthesis.
Consumers
• Organisms that cannot make their own
source of food (e.g. animals) to get energy
have to get it by eating or “consuming”
other organisms.
• As organisms eat each other, the energy is
passed from one organism to another.
• We can show this in a FOOD CHAIN.
Decomposers
• Decay dead material and help recycle
nutrients
Physical
• Non-biological components (abiotic)
– Water
– Soil
– Rocks
Ecosystems
• Complete the table of Biotic and Abiotic
organisms we have discussed.
Habitats
• Within each ecosystem there are a range of
habitats
– Grasses
– Ponds
– Trees
– Litter
Populations
Populations
• Within the ecosystem are organisms of a
particular species.
• These make up a particular population
Communities
• The population of all species in a particular
ecosystem at any one time form a
community
Factors Affecting Animals
• Water
• Food
• Space
• Predators
• Disease
• Seasons/Weather
Factors Affecting Plants
• Water
• Food
• Space
• Insects
• Disease
• Seasons/Weather
• Sun
Carrying Capacity
• The carrying capacity of a biological
species in an environment is the population
size of the species that the environment
can sustain indefinitely, given the food,
habitat, water and other necessities
available in the environment.
Population graphs
• The growth of a wild population can be
logged on a graph.
• The graph line looks like a flattened “S”. It
is called a sigmoid curve.
• This graph shows 4 phases of population
growth.
Population graphs
1. A slow start when
there are only a few
fertile members
2. Maximum growth
when birth rate
greatly exceeds
death rate.
Population graphs
3. Decelerating growth
as environmental
resistance starts
(e.g. lack of food)
4. Steady population
numbers when the
birth rate and death
rate is about equal.
Stages of Population Growth
• Stage 1 decrease in birth rates
• Stage 2 birth rates greater that death rates
• Stage 3 death rates begin to increase
• Stage 4 birth and death rates remain low
•
Population Growth
• All populations undergo three distinct
phases of their life cycle:
• growth
• stability
• decline
Interaction In An Ecosystem
Interaction in An Ecosystem
• Organisms in an ecosystem are continually
interacting with each other
– Feeding among the organisms
– Competing with each other
– Interaction between organisms and the
environment
Interaction in An Ecosystem
• As organisms eat each other energy some
energy is passed on
• Most energy is lost in the form of heat and
waste.
• All energy originates from the sun.
Interaction in An Ecosystem
• Plants trap solar energy to produce
chemical energy in the form of glucose
• Process called photosynthesis
Interaction in An Ecosystem
• Organisms that convert solar energy to
chemical energy are called producers
– autotrophic
• “They produce their own energy”
C6H12O6
Interaction in An Ecosystem
• Organisms that consume producers for
energy are called consumers
– Heterotrophic
• As organisms consume each other they will
transfer some of the energy. However,
most is lost in the form of heat.
Feeding Relations
• Feeding relationships are best illustrated
with food chains
Food Chains
Rabbits eat grass. Foxes eat rabbits.
Energy from the sun
is transferred to
chemical energy by
photosynthesis
When the rabbit
eats the grass, the
energy stored in the
grass is transferred
to the rabbit.
Rabbit
That’s what the
arrow is showing!
When the fox eats
the rabbit, the
energy stored in the
rabbit is transferred
to the fox.
Grass
Fox
Grass Rabbit Fox
• The arrow in the food chain means
“eaten by”
Primary and Secondary
consumers
• The primary consumer is the first consumer
in the food chain. These eat the plants
• The secondary consumer is the second
consumer in the food chain. These eat
other animals.
Producers and Consumers
Worm Leaf
Bird
Producer ________
consumer
________
consumer
Tropic Levels
• The different stages in a food chain
– Producer, consumer, consumer
Feeding Relations
• Herbivore
• Carnivore
• Omnivore
Food Chain
• Most food chains go up to only 5.
• Why is this?
Decomposers
• Decomposers are bacteria and fungi.
• They get their food by decomposing
(breaking down) dead plants and animals in
to simple substances like carbon dioxide,
nitrates and other minerals.
• They are very important because they
provide all the nutrients in the soil for plants
to grow.
The Circle of Life!!
Round and round
The nutrients go!!
Yum. Tasty
plant
Yum. Tasty
bug
Yum.
Tasty
nitrates!
Food webs
• Obviously, all organisms eat a variety of
food shown by many food chains.
• We can link these food chains together to
make food webs.
• Look at these food chains:
Food chains
• Leaves earthworm hedgehog
• Leaves earthworm fox
• Leaves rabbit fox
• Leaves caterpillar hedgehog
Link the food chains together to make a
food web
Leaves
rabbit
hedgehog
More!
• Blackbirds eat earthworms, Falcons eat
rabbits and blackbirds.
• Add Falcons and blackbirds to your food
web.
Ecological Pyramids
Ecological pyramids
• Diagrams that represent the relative
amounts of organisms at each trophic level
in a food chain
– Pyramid of numbers
– Pyramid of biomass
– Pyramid of energy
Key points
• Pyramids of number show the number of
living organisms at each stage of the food
chain (trophic level).
Key points
• Look at this food chain:
Wheat Mice Owl
50 10 2
• Complete the paragraph in your worksheet.
• Complete the pyramid 2 owls
10 mice
50 wheat
Pyramids of number are not always
pyramidal in shape…
• Grass Rabbit Fox
– 200 blades of grass
– 6 rabbits
– 1 fox
– 25 fleas
• Oak tree
Caterpillar
sparrow
– 1 oak tree
– 150 caterpillars
– 25 sparrows
Grass
Rabbit
Fox
Caterpillar
Tree
Sparrow
Key points
• We use Pyramids of Biomass to show the
amount of energy available at each trophic
level (level of the food chain).
Key Points
• If we draw a pyramid of Biomass it will always look like a pyramid:
• There is always less biomass as you go up the food chain because energy is always lost. – (Not all the energy in the plant is transferred to the
primary consumer and not all the energy in the primary consumer is transferred to the secondary consumer.)
Grain
Cow
Human
Energy Pyramid
Only 5 to 20% of energy is transferred
to the next trophic level due to:
• predator avoidance
• not all digestible
• not all accessible
• all organisms respire
• 10% used as a rule of thumb by
ecologists
Hmmm….
• Considering the energy gets less and less
as you move up the food chain, wouldn’t it
be better for humans to eat grain?
Wouldn’t we get more energy that way??
Grain
Cow
Human
Answer…
• However, energy isn’t the only reason to
eat food and other food is eaten to get a
balanced diet.
YES!!!!! There is more energy available in plant products compared to animal products. This is because there is always more energy the further down a food chain you eat.
Summary
• Energy is lost in a food chain due to:
– Movement
– Excretion
– To keep a warm blooded animal at the right temperature
• Useful energy is energy used to make an organism bigger. Only this energy can be passed on to another organism when it is eaten.