© Weston, 2010

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 of organization 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 all of the same species. What do we call this group? More populations:

#4 What do populations combine to make? This is a collection of populations of several different species. What is this called? A simple community.

Well, these living creatures have life demands…they have requirements 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 2 I.Levels of Organization A. Organism – one whole, living thing B. Population – group of living things of the same species C. Community – collection of populations of different species D. 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 Serengeti Plains of Africa, a very interesting ecosystem

#7 Components of Ecosystems So, 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 taking biology as a class right now. Biology is the science of living things. Bio = life. Just look at these textbook covers for proof. Scientists call the living components of an ecosystem the biotic factors. Biotic factors are all the components of an ecosystem created by living things. Let’s see more…

#9 Biotic Factors of an Ecosystem Examine 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 2 I.Levels of Organization A. Organism – one whole, living thing B. Population – group of living things of the same species C. Community – collection of populations of different species D. Ecosystem – all the living & nonliving things in an area. II.Components of Ecosystems A. 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 ecosystem Abiotic factors are all of the components in an ecosystem that were never alive and never will be. They are still critical to the survival and health of the ecosystem.

#13 Write. II.Components of Ecosystems A. Biotic Factors – living things and their products ex: plants, animals, feces, bones, twigs B.Abiotic Factors – non-living factors needed for life ex: 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 community or ecosystem? What are the biotic and abiotic components?

#14 An organism’s place in an ecosystem When you think about what goes on in a forest, or a field, or in the ocean, it seems like every organism has its place, or its role. For example, compare these two organisms. It’s very likely that both could live side-by-side. Both share similar food sources and even appear in the same position in a food 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 would think 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 play drastically 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 want to 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 is going to only be preyed upon by fairly large consumers like wolves or coyotes. 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 practice All 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: Sun moss pecan tree The moss’s niche is to be a small producer, living close to the ground, spreading very quickly. It will be found in moist environments, providing food and a home to insects and other 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 likely huge 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 the ground and high in its canopy. That’s the niche of a pecan tree. Get it now?

#17 Write about “niche” II.Components of Ecosystems A. Biotic Factors – living things and their products ex: plants, animals, feces, bones, twigs B.Abiotic Factors – non-living factors needed for life ex: 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 ecology One definition of ecology reads, “the study of the interactions of organisms with each other and their environment.” This definition highlights the importance of remembering that organisms in ecosystems are in constant relationships with other organisms and also the abiotic factors they live in. And don’t forget this: Characteristics of Living Things: 1.All living things grow 2.All living things reproduce 3.All living things use energy 4.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 turn on the kitchen light? What does a maple tree do when it detects that autumn is coming? What does a grizzly bear do when you poke it with a stick? Only one way to find out…

#19 Two types of stimuli Stimulus 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 the opposite. These are conditions that are occurring outside of the organism that it notices or detects. The organism must then respond to these stimuli.

#20 Internal Stimuli & Responses Think of all the changing conditions that an organism might need to respond to. Here’s just a sample: And here are some specific responses to these internal stimuli. Forget shivering… Where’s my hoodie?!?

#21 External Stimuli & Responses External stimuli can be a little more complicated. Let’s see how. EXTERNAL STIMULUSRESPONSE 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 conditions coming 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 the complicated 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 ones IV. Stimulus (changing condition) and Response A.Internal Stimulus – detected inside an organism ex: hunger, emotions, temperature B.External Stimulus – detected outside ex: 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 6 th grade science stuff. Hopefully, seeing me get blown away by a tornado, electrocuted, throw up at Six Flags, get kicked off a mountain, and eaten by spiders helped you learn some things. Well, see ya…I’ve got to figure out how to get Rex’s squeaky toy from under the fridge… Bye, Joe. May you live in interesting times…

#25 And That’s…