Tuesday October 6th
In Notebook:
What is the difference between
primary and secondary
succession?
Today’s Learning Targets
Agenda:
1. Succession Review
2. Trophic Levels / Food Web
3. Quiz Tomorrow: Cycles & Levels of Organization
On a bright spring day the sun shines onto the forest floor. The warm weather and the moist
soil cause plants to sprout. Up through the dead and decomposing leaves (humus) come
spring beauties, larkspurs, and other spring flowers. The old oak trees unfold their new
leaves, and within a matter of days the leaves begin to produce food by photosynthesis.
Mushrooms pop up around rotting logs, and beetle larvae (tiger beetle) feast on the
mushrooms and decayed wood. Soon the spring warmth triggers the hatching of linden
looper caterpillar eggs, and these young caterpillars crawl onto the tender oak leaves and
begin feeding. The new tree and understory foliage allow a female deer to eat well; in turn,
she provides food to her fawn in the form of milk. The doe rubs her leg against a rough tree
because a flea has just bitten her.
Earthworms tunnel through the moist earth, leaving behind little piles of soil in which
wildflower seeds will sprout. Aphids find the young oak leaves juicy and nourishing. The
aphids stick their needlelike mouth parts into the oak's stems and suck its juice. A bright green
tiger beetle walks along sunny forest paths searching for its dinner--linden looper larvae that
have fallen off the oak foliage. Elsewhere, spiders spin webs to catch unsuspecting insects
like midges and young grasshoppers.
Another inhabitant of the forest, a white-footed mouse, comes out and searches for food-wildflower seeds, mushrooms, acorns (oak trees), and any caterpillars it finds. Grackles and
robins begin courtship and will soon feed caterpillars and earthworms to their young in the
nests in the oaks. Linden looper caterpillars have other enemies besides the birds and
beetles. A tiny wasp parasite lays her eggs on the caterpillar and the young wasp will feed on
it (from the inside out!) until fully grown. As the season progresses, the young birds and mice
must be wary of owls and hawks, the deer and fawn wary of the hunter . . . .
•
Why do we eat? What characteristic of life has to do with food?
ENERGY! When we eat we obtain energy and pass on that energy when
someone eats us.
•
Where does the energy initially come from?
It will always start with energy from the sun. ** We will discuss how much
energy is passed on tomorrow.
•
Are food webs simple or complex?
Complex. Many species can eat multiple species or be eaten by multiple
species.
•
Where is the end of a food web?
The last shown organism is the top predator, but ultimately all organisms can
die and decay and decomposers will break down the organism.
Food Web vs. Food Chain
2 Main Trophic Levels
(Classified based on how they obtain energy)
Autotroph
Heterotroph
Auto-: occurring within
Hetero-: another
-troph: nourish
-troph: nourish
* Make their own food!
* Eat other organisms!
Degrees of Heterotrophs
Aka - consumers
Primary consumers - eat plants
Secondary consumers - eat primary consumers
Tertiary consumers - eat secondary consumers
...
Types of Heterotrophs
(Match them up using prior knowledge!)
•
Herbivore
Eats both meat and plants
•
Carnivore
Eats plants
•
Omnivore
Eats decomposing matter
•
Detritivore
Eats meat
** Based on what the organism can receive
energy/nutrients from! **
Ready for a catchy
tune??
Ecological Food Pyramid