© Weston, 2010

Ecosystems

Ecosystems

Ecosystems

Ecosystems

Ecosystems

Ecosystems

Let’s let Joe, um…collect himself…and talk some more about ecology.

#1 What exactly do we mean by “ecosystem”?

To answer that question, we need to go back and review a concept from the last unit.

Arrange these items from most simple to most complex:

The organism is the most complex level oforganization in this list.

Just remember…an organism is one individual, whole, complete living thing. You are an organism. So are these things:

But…we don’t necessarily have to stop there.

#2 Continuing the levels of organization

This is one organism. One whole,living thing.

#3 What comes next?

This is a group of organisms. They are allof the same species. What do we call thisgroup?

More populations:

#4 What do populations combine to make?

This is a collection of populations of severaldifferent species. What is this called?

A simplecommunity.

Well, these living creatures have life demands…they haverequirements of their environments, such as:•An atmosphere to live in

•Soil to walk on, dig in, grow in, etc.

•Sunlight and a moderate temperature

#5 What comes next, after communities?

•Water, for numerous life functions

What we’re describing is the combination of all of the living and nonliving things in an area. This is a(n)…

Write Your Name

Notes – Ecology Part 2I. Levels of Organization

A. Organism – one whole, living thingB. Population – group of living things of the same

speciesC. Community – collection of populations of

different speciesD. Ecosystem – all the living & nonliving things

in an area.You’ll learn more about what happens when you go beyond “ecosystems” in future years. For now, just remember that an ecosystem has living and nonliving components.

#6 Write.

The SerengetiPlains of Africa, a veryinterestingecosystem

#7 Components of EcosystemsSo, here are some ecosystems:

What do they have in common?

What makes up an ecosystem?

Remember that a community just involves living organisms. The ecosystem, however, involves both living organisms and non-living factors, too.

Scientists have names for these living and non-living components of ecosystems.

#8 The Living Components of Ecosystems

If you have a brother or sister in high school, there’s a good chance that he/she is takingbiology as a class right now. Biology is the science of living things. Bio = life. Just lookat these textbook covers for proof.

Scientists call the living components of an ecosystem the biotic factors. Biotic factorsare all the components of an ecosystem created by living things. Let’s see more…

#9 Biotic Factors of an EcosystemExamine this scene. What are the biotic factors or components in this ecosystem?Remember, biotic factors are living things or products of living things.

#10 Write.

Notes – Ecology Part 2I. Levels of Organization

A. Organism – one whole, living thingB. Population – group of living things of the same

speciesC. Community – collection of populations of

different speciesD. Ecosystem – all the living & nonliving things

in an area.

II. Components of EcosystemsA. Biotic Factors – living things and their products

ex: plants, animals, feces, bones, twigs

Alive & biotic

Dead, but still biotic

#11 So, what are the dead…err, not dead…what are the non-living components?

You remember the difference between sexual reproduction and asexual reproduction?

Basically, they’re opposites.

Biotic factors have an opposite, too. I imagine you can guess what they’re called.Here are some hints.

In his life, Joe has proven to be abrave. And we’ve seen him be awise.

#12 Abiotic Factors in an ecosystemAbiotic factors are all of the components in an ecosystem that were never alive andnever will be. They are still critical to the survival and health of the ecosystem.

#13 Write.

II. Components of EcosystemsA. Biotic Factors – living things and their products

ex: plants, animals, feces, bones, twigs

B. Abiotic Factors – non-living factors neededfor lifeex: air, temperature, light, water, dirt

So, when you move up from the community level (just living things) to the ecosystem level (everything), you’re adding abiotic factors to biotic ones.

Is this a communityor ecosystem?

What are the bioticand abiotic components?

#14 An organism’s place in an ecosystemWhen you think about what goes on in a forest, or a field, or in the ocean, it seems likeevery organism has its place, or its role.

For example, compare these two organisms.

It’s very likely that bothcould live side-by-side.Both share similar foodsources and even appearin the same position in afood web.

Sun grass

Yep…they’re both consumers. Primary consumers, to be precise.

But they sure do seem to have different roles in an ecosystem…I mean, nobody wouldthink that grasshoppers and deer are just interchangeable.

“Hey, Jim…this forest is really low on deer from all the hunting.” “That’s ok, Bob, we’ll just bring in grasshoppers to replace ‘em.”

#15 The concept of “niche”A deer and a grasshopper may both play similar roles in a food chain, but they playdrastically different roles in an ecosystem.

This concept is described by the word “niche.” Niche can be pronounced two ways:

Niche can rhyme with a word that describes a mean woman that Dorothy didn’t wantto bump into.

Or it can rhyme with…well…I can’t think of a word that sounds like“neeeesh”.

Oh well.

A deer’s place in an ecosystem is to be a large herbivore. A deer isgoing to only be preyed upon by fairly large consumers like wolves orcoyotes. Deer will eat a good amount of close-to-the ground vegetation, which is harmful for certain plants. Deer will eat and pass seeds in their droppings, which is good for plants. The population of deer will be closely tied to the population of plants it eats and consumers that eat the deer. THAT IS A DEER’S NICHE.

How many of those things are true or different for a grasshopper? Different niche.

#16 More niche practiceAll plants are producers. Cool. They are all drawn in the same place in any food

web...right at the start (after the Sun).

But it’s ridiculous to think that these two plants fill the same niche:

Sunmoss

pecan tree

The moss’s niche is to be a small producer, living close to the ground, spreading veryquickly. It will be found in moist environments, providing food and a home to insects andother small animals. It will be found along or very close to the ground. Moss’s niche.

The pecan tree has a totally different niche. The tree will be a slow-growing, but likelyhuge producer that dominates its area. It will provide food for medium or large herbivores. It will shade much of the area beneath it, allowing only smaller plants to live in its area. It will provide a home for numerous animals and insects both near theground and high in its canopy. That’s the niche of a pecan tree. Get it now?

#17 Write about “niche”

II. Components of EcosystemsA. Biotic Factors – living things and their products

ex: plants, animals, feces, bones, twigs

B. Abiotic Factors – non-living factors neededfor lifeex: air, temperature, light, water, dirt

III. Niche – the role an organism has in its ecosystem.ex: a frog will feed on smaller animals near water,

and will provide food for larger ones

#18 A key part of ecologyOne definition of ecology reads, “the study of the interactions of organisms with eachother and their environment.”

This definition highlights the importance of remembering that organisms in ecosystemsare in constant relationships with other organisms and also the abiotic factors they livein.

And don’t forget this:

Characteristics of Living Things:1. All living things grow2. All living things reproduce3. All living things use energy4. All living things are made of cell(s)5. All living things respond to stimuli

All living things respond to stimuli.

What does a cockroach do when you turnon the kitchen light?

What does a maple tree do when it detectsthat autumn is coming?

What does a grizzly bear do when you pokeit with a stick?

#19 Two types of stimuliStimulus is the singular. Like 1 cactus or 1 octopus.Stimuli is the plural. Like 3 cacti or 7,443,035 octopi.

Internal stimuli are exactly that—from within the organism. These are conditions that require the organism to respond (take some action to deal with it).

INTERNAL organs

External stimuli are theopposite. These are conditions that are occurringoutside of the organism thatit notices or detects. Theorganism must then respondto these stimuli.

#20 Internal Stimuli & ResponsesThink of all the changing conditions that an organism might need to respond to. Here’sjust a sample:

And here are some specificresponses to these internalstimuli.

Forget shivering…

Where’s my hoodie?!?

#21 External Stimuli & ResponsesExternal stimuli can be a little more complicated. Let’s see how.

EXTERNAL STIMULUS RESPONSE

•Bright sunlight •Squinting (ok, this one is pretty simple)

•Shorter days, colder temperatures

•Trees drop their leaves in autumn

•Increasingly hot weather •Dogs shed their thick coats in late spring

•Sunlight, motion of the Sun. •Plants grow toward the Sun’s position.

•Difficult survival conditionscoming up

•Hibernation (chipmunks sleep through cold months)•Migration (geese fly to warmer weather & easy food)•Dormancy (grass turns brown in winter instead of

trying to grow & stay green)

There really are countless more examples, from as simple to an itch on your arm to thecomplicated conditions that cause plants to realize winter is over and fire back into life.

#22 Write.

III. Niche – the role an organism has in its ecosystem.ex: a frog will feed on smaller animals near water,

and will provide food for larger onesIV. Stimulus (changing condition) and Response

A. Internal Stimulus – detected inside an organismex: hunger, emotions, temperature

B. External Stimulus – detected outsideex: light, dark, climate change

Organisms respond to these stimuli to help increase their chances at survival. When you learn more about the human body, you might be astonished to discover the numerous stimuli, both internal and external,that your nerves and brain can respond to.

#23 Looks like Joe is prepared to handle some stimuli…

Yep, sure am.

And don’t think I forgot to pack one

other thing…

#24 And That’s…

Gosh, it was nice being your guinea pig while learning all this 6th grade sciencestuff. Hopefully, seeing me get blown

away by a tornado, electrocuted, throw upat Six Flags, get kicked off a mountain, and

eaten by spiders helped you learn somethings.

Well, see ya…I’ve got to figure out how toget Rex’s squeaky toy from under the

fridge…

Bye, Joe. May you live in interesting times…

#25 And That’s…