Transcript Ecology and Energy Movement...an overview

© Weston, 2010
ECOLOGY in 45 minutes!
The diversity of life on Earth is a beautiful thing. Otherwise, what a boring world we’d
have to observe around us…
#1 What’s Ecology?
Ecology is a branch of biology (the science of living things). Ecology focuses on how
organisms relate to each other and their environment to survive. Ecology is the science
highlighted by shows you’ve probably seen on TV…
#2 Write.
Write.your.name
Notes – Ecology & Energy
I. Ecology – the study of how organisms relate to each
other and their environments.
This ecologist is prepared to collect samples that will
determine how diverse & healthy this ecosystem is.
#3 Food Chains
You’ve probably learned food chains in prior years. The thing to remember is that a food
chain shows energy flow. In other words, the arrows need to show where energy is going
to, not where it is coming from.
There are different roles in the food chain. Let’s review them here.
Question: What one object allows for life on Earth to continue on?
Did you really say that? You meant to say:
The Sun is the primary energy source for almost all
food chains on Earth. The only exception is in ecosystems at the bottom of oceans near tectonic vents.
The Sun’s energy, converted into food during
photosynthesis, is the PRIMARY ENERGY SOURCE
for all practical food chains.
#4 Producers
Animals can’t do squat with the Sun’s energy for food purposes—it just warms us up and
makes us feel nice n’ toasty.
Plants have an absolutely fascinating ability to convert sunlight into sugar. Sugar CAN be
useful to animals, which is good news for everyone in the food chain (except for the plants
about to be eaten, of course).
Plants are called PRODUCERS because they “produce” a usable form of energy from an
unusable form. You may not think plants are cool and may hate eating your veggies, but
you should hug a tree or a shrub or a weed the next time you see one, because without
plants, there’d be no animals on Earth.
#5 Primary Consumers
What’s it mean to consume?
Once producers have worked their photosynthetic
magic and made usable sugar, certain animals
will be right there ready to gobble it up.
PRIMARY CONSUMERS eat plants. In other
words, we’re talking about herbivores here.
Primary means “1st” so that probably gives you a
hint as to what comes next.
Um, yeah…pretty much.
#6 Secondary Consumers
A grasshopper has chewed up a whole bunch of grass. Yum. Suddenly, a turkey runs
over and destroys the insect with its beak, then eats it. Yum.
The turkey acts as a SECONDARY CONSUMER here. We’re talking about carnivores
or omnivores—animals that get their energy by mainly eating other animals.
Secondary consumers can then be eaten by other consumers (called tertiary
consumers), such as if a human kills and eats the turkey in late November. Scavengers
count as secondary consumers, too—there’s no difference in energy flow if a vulture
first kills a squirrel then eats it or if the vulture waits til it dies of old age.
#7 Decomposers
Once a tree dies and becomes a log, or armadillo roadkill has been picked-clean by
vultures, there’s bound to still be nutrients remaining in the carcass. Here’s where
decomposers come into play.
DECOMPOSERS decay dead organic matter. We’re talking about fungi and bacteria.
Scavengers just eat leftovers. Decomposers actually finish the process off. Decomposers
play a very important role in ecosystems, as they release stored-up nutrients in dead
carcasses which get used by living plants in the area. If this helps plants get healthier,
then it helps the consumers that eat the plants get healthier, and so on and so on. 
#8 A Sample Food Chain
Sun
Seaweed (Producer)
Seal (Secondary Consumer)
Carp (Primary Consumer)
Bacteria (Decomposer)
Gotta start with the Primary Energy Source.
Arrows show where energy goes to.
Just because the bacteria take energy
from the seal doesn’t necessarily imply
that they killed the seal. Nope, they
just had to eat it for the arrow to make
sense. The seal could’ve drowned or
been killed in a storm…who knows?
Moreover, if we had fit in a Killer Whale between the Seal and Bacteria, the Killer Whale
would’ve acted as a tertiary consumer in this food chain. Simple stuff, so you just need
to remember the basics.
#9 Food Chain, Summarized
Sun
Seaweed (Producer)
Seal (Secondary Consumer)
Carp (Primary Consumer)
Bacteria (Decomposer)
Remember, a food chain shows the flow of energy from one object or organism to
the next.
That’s why the arrows don’t point at what gets eaten…the arrows point at what is
DOING the “eating.” The arrows show where the energy goes to. The food chain in
blue could be read like this:
•The Sun gives its energy to seaweed, a producer.
•The seaweed gives its energy to a carp, a consumer.
•The carp gives its energy to a seal, another consumer.
•The seal (or carp or seaweed) gives its energy to bacteria, which decompose all the
dead organisms in the area.
#10 Write!
Ecology – the study of how organisms relate to each
other and their environments.
II. Food Chain – a diagram showing how energy flows
in an ecosystem. Arrows show where energy goes to.
I.
Example: Sun  grass  cricket  chicken
A. Roles
i. producers – use sunlight to produce useable
food energy (plants!)
ii. consumers – get energy by eating producers or
other consumers (animals!)
iii. decomposers – break down formerly living
matter into useable nutrients (fungi/bacteria!)
#11 Taking advantage of
decomposers
How does a bird egg stay warm enough so that the chick doesn’t die of cold?
Alligators don’t sit on their eggs—they just leave
‘em. So how do those eggs not die?
The mama alligator piles up leaves and twigs all
above the eggs. These no-longer-alive plant bits
will start decomposing, thanks to bacteria.
As the leaves decompose, the temperature of the
nest increases, which keeps the eggs at the proper
temperature for development.
People can take advantage of decomposition in a similar way—not to keep our eggs
warm, because most people don’t lay eggs—but rather in a compost heap. Compost
describes storing formerly living matter (leaves & twigs, leftover food, animal manure,
etc.) to let the decomposition process begin. After a while, much of this material will
have decomposed, which frees up valuable nutrients to be spread in gardens and
lawns. It’s an easy way to avoid the use of harsh chemical fertilizers while helping to
avoid making too much waste. More and more people are composting…will you?
#12 Write
A. Roles
i. producers – use sunlight to produce useable
food energy (plants!)
ii. consumers – get energy by eating producers or
other consumers (animals!)
iii. decomposers – break down formerly living
matter into useable nutrients (fungi/bacteria!)
•Compost – using decomposition to turn
formerly-living matter into fertilizer
#13 Energy Pyramids & the
10% Rule
An Energy Pyramid shows
the flow of and amount of
energy at different levels in an
ecosystem. Think of it as an
alternate way to draw a food
chain. They almost always
leave out the Sun and
decomposers, and focus on the
entities in the middle.
The shape of the pyramid
suggests there are more insects
than owls in this food chain.
There’s more grass than there
are rodents by a lot, too. The
10% Rule describes how only
about 10% of the energy makes it from one level to the next. Where is the 90% of energy
then? The majority of eaten (consumed) energy is lost as heat to the environment during
metabolism—it’s not saved as stored-up energy to be eaten by the next higher-level.
#14 Write
A. Roles
i. producers – use sunlight to produce useable
food energy (plants!)
ii. consumers – get energy by eating producers or
other consumers (animals!)
iii. decomposers – break down formerly living
matter into useable nutrients (fungi/bacteria!)
•Compost – using decomposition to turn
formerly-living matter into fertilizer
B. Energy Pyramid – diagram that shows much
more energy exists early in food chain. Less is
available for consumers at the end.
#15 Add a sample Energy
Pyramid
Energy in Consumers
Energy in Producers
SUNLIGHT ENERGY
This type of energy pyramid describes what you may have noticed while watching
nature shows on TV.
In this picture, what is the most abundant
type of living things?
PLANTS!
Then there are lots of herbivores, and
very, very few top predators.
For every lion or cheetah in Africa, there
may be hundreds of zebra or wildebeest.
That’s the energy pyramid.
#16 And That’s…