Welcome to Ecology
What is Ecology?
Welcome to the Anthropocene…
Inquiry Activity
• In groups of 2-3, you have five minutes to
make a list of all of the types of organisms,
including plants, humans, animals, insects etc
that you have seen in a specific location.
• Rainforest
• Tundra!
Inquiry Activity
• Make a diagram that shows how the
organisms that you listed interact with each
other.
• Who eats who/what?
• Where do these organisms live?
Think About It
1. Which organisms on your list provide energy
or nutrients to the others?
2. What would you expect to happen if all the
plants in your diagram died? EXPLAIN your
answer.
3. Why is it difficult to make accurate predictions
about changes in communities of organisms?
1. Ecology Definitions
3.1: What is ecology?
• Ecology is the scientific study of interactions
among organisms and between organisms
and their environment
• Etymology (word Root): eco comes from the Greek
oikos which means house.
The Biosphere
The biosphere contains
the combined portions
of the Earth in which all
life exists, including
land, water and air or
atmosphere.
It extends 8 km above the
Earth’s surface and as
far as 11 km below the
surface of the ocean.
Within the Biosphere are levels of
organization
1. Ecology Definitions: Feeding
relationships
Autotrophs/ Producers/ (Trophic Level
1)
Food energy is most
commonly produced
from light energy
through photosynthesis
Some autotrophs can
produce food energy
without light, instead
using chemicals like
hydrogen sulfide. These
autotrophs use a
process called
chemiosynthesis.
Chemotrophs
Some autotrophs can
produce food energy
without light, instead they
use chemicals like
hydrogen sulfide. These
autotrophs use a process
called chemiosynthesis.
Let’s meet some…
Deep Sea Challenger
Compare chemosynthesis
with photosynthesis
Giant Amoeba
Heterotrophs/ Consumers (and
decomposers)
Organisms that rely on other organisms for
food are called heterotrophs or consumers.
Decomposers can be detrivores or
saprotrophs
• detritus 1
• detritus 2
Decomposers (bacteria
and fungi) recycle
nutrients (organic
matter and other
essential elements) in
an ecosystem
3. Feeding relationship: Food
webs and food chains
Food chains show how food passes
from one living thing to another
All food chains start with a Plant
Plants can make their own food,
using sunlight
FOX
RABBIT
An animal that eats
other animals
GRASS
An animal that
eats plants
A plant - makes its
own food
The arrows
show the
food chain
FOX
RABBIT
An animal that eats
other animals
GRASS
An animal that
eats plants
The plant is a
‘producer’
A plant - makes its
PRODUCER
own food
FOX
RABBIT
An animal that eats
other animals
GRASS
An animal that
CONSUMER
eats plants
A plant - makes its
PRODUCER
own food
The rabbit is a
‘consumer’ - a
herbivore or
plant-eater
FOX
RABBIT
An animal that
CONSUMER
eats
other animals
GRASS
An animal that
CONSUMER
eats plants
A plant - makes its
PRODUCER
own food
The fox is also a
‘consumer’ - a
predator or meateater
Food chains and food webs work in
the same way in the sea ...
… but the plants and animals look a
bit different!
FISH
COPEPOD
ALGAE
Out in the ocean, there
is no grass or trees
An animal that eats
other animals
The plants are tiny
animal
ALGAE A-tiny
you
need a
that eats plants
microscope to see them
Microscopic plants make their own food
This is a food
chain in the ocean
FISH
COPEPOD
ALGAE
Out in the ocean, there
is no grass or trees
CONSUMER
PRODUCER
CONSUMER
The food chain won’t stop there ...
In most habitats, there are several
food chains
These are linked together to form a
Food Web
Food webs can be quite complicated
Here is one from the ocean around
Antarctica …
Seals eat squid
Squid eat fish
and krilland fish
Fish eat krill and
copepods
A simple food chain
whale eats krill eats
algae
Copepods also eat
algae, and are eaten
This food web contains 7 types of living
things, and 9 food chains
by krill
1. Ecology Definitions: Pyramids of
energy/ biomass/ numbers
We often use BIOMASS in order to
evaluate changes in energy in food
chains/webs
Not all energy from food is turned into
tissue ‘growth’
• A lot of food energy is used to provide energy
for heat, warmth, cellular respiration…
• Some is indigestible, and is ‘lost’ (e.g.
cellulose, teeth, claws, skin…)
An example: krill feeding on algae
This leaves 10
grammes of food
that can be used
for growth
70 grammes of
algae eaten per day
50 grammes of food are
used to provide energy for
swimming and catching
more food
10 grammes - about
15% - is indigestible
10 grammes to
growth
= 15% of food
eaten
50 grammes
70 grammes
‘in’
= 100%
plus
10 grammes
‘to waste’
= 85% of food eaten
The same thing happens at every
step along the food chain
Look at the food web from Antarctica
...
A large blue whale will eat
3 tonnes of krill each day
The amount of growth will
be 120 kilogrammes -96%
of the food has ‘gone to
waste’
The rate at which animals grow is
often related to their body size
FOX
RABBIT
GRASS
On land,
herbivores and
predators are
often similar in
size
Making the krill 1000 timesMaking the whale
times bigger
bigger means
thatdifferences
it becomes1000
as
We can understand
the size
more easily if
means
that itare
is still
In
the
oceans,
both
and
herbivores
longthe
as plants
a small
bustheobjects.
we
match
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Here,
Making
alga
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1000size
times
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means
thatstretch
it
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-between
it would
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There
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we magnify
each
1000
times
is about
the
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across
herbivores and predators
Not all energy from food is turned into
tissue ‘growth’
• A lot of food energy is used to provide energy
for heat, warmth, cellular respiration…
• Some is indigestible, and is ‘lost’ (e.g.
cellulose, teeth, claws, skin…)
• This happens at EACH LINK in the food chain…
The shortest food chain in the
Antarctic food web has two links
LOSS
LOSS
For 100 TONNES of algal growth…
• You get 15 tons of new krill growth
• And only 600 kg of new whale growth
The longest food chain in the
Antarctic food web has five links
LOSS
LOSS
LOSS
LOSS
LOSS
Now, for 100 tonnes of algal growth
• There is 1 kg of seal growth
• Which means that 99.999% of the energy of
the algae eaten by the copepods has been
‘lost’
In the food chain with more links,
more producer growth is lost
You have seen that -
A food chain links plants
and animals in a habitat
All food chains start with a
plant = producer
You have seen that -
Food webs on land and in
the ocean are similar
In the ocean, plants and
herbivores are small
You have seen that -
Most food in a food chain
is turned into energy and
lost
Long food chains waste
more food than short
ones