between plants, animals and their environment. They are systems that demonstrate how organisms interact with each

Transcription

1 75 humidity level grass in a field Activity are the interactions ecosystems ALABAMA 7TH GRAD SCINC STANDARDS COVRD IN THIS CHAPTR INCLUD: Chapter 9 cosystem nergy ASA z LO CO w -J I- CO CU C) C) granite bedrock Fill in the table below with biotic or abiotic nitrogen in the air beavers building a dam dam built by beavers Type of Factor xample bacteria in the soil salt content of seawater called abiotic factors Things like rocks, soil, air, sunlight, shade, chemicals or temperature are all abiotic factors So, to put it all together, an ecosystem is roughly defined as the interaction between the abiotic and biotic factors in an area Remember, it is not defined by its size; it can be as large as a desert or as small as a puddle It is a system! factors include plants, animals, fungi bacteria and protists Non-living things are ecosystems are called biotic factors Some examples ofbiotic ABCO35 other and their physical environment Living things in q;wwlrrzl1 systems that demonstrate how organisms interact with each INKS between plants, animals and their environment They are Sc - You might remember BioTic AND ABITIc FACTORS 7 Describe biotic and abiotic factors in the environment

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3 - Chapter 9 INTRACTION AND INTRDPNDNC Matter within an ecosystem is constantly recycled over and over again lements, chemical compounds and other sources ofmafter pass from one state to another through the ecosystem This is called an energy cycle As a deer eats grass, the nutrients contained in the grass are broken down into their chemical parts and then rearranged to become living deer tissue Waste products (feces) are produced in the deer s digestive system and pass from the deer s body back into the ecosystem Organisms break down this waste into simpler chemical components The grass growing close by is able to take up those components and utilize them; they become a part of the grass Then the cycle begins again The nergy Cycle :: Consumer Producers / ) :::;--:9 Ofl%UflK I o Figure 91 nergy Cycle FooD CHAINS AND FOOD WBS The consumers producers, and decomposers of each ecosystem make up a food chain nergy flow through an ecosystem Grasshopper g F I Puma occurs in food chains, / with energy passing from I / : \,- one organism to another c r1k\_ fecomosers There can be many food chains within a single ecosystem :- PRODUCR CONSUMRS Raccoon figure 92 A Food Chain > 77

4 energy cosystem nergy The producers of an ecosystem use abiotic (not living) factors to obtain and store for themselves or the consumers that eat them In a forest ecosystem, th&\ producers are: trees, bushes, shrubs, herbs, grass, vines and moss Producers are sometimes called autotrophs Consumers, also called heterotrophs, are members of the ecosystem that depend on other members for food ach time a plant or animal consumes another organism, energy transfers to the consumer Deer, foxes, rabbits, raccoons, owls, hawks, snakes, mice, spiders and insects are examples of consumers in a forest ecosystem There are three types of consumers: herbivores, carnivores and omnivores Table 9 1 lists characteristics ofthe three different types of consumers Table 9 1 What Different Consumers at Consumer Herbivore Omnivore Carnivore Saprophyte Food Supply animals that eat only plants animals that eat both plants and other animals animals that eat only other animals organisms that obtain food from dead organisms or from the waste products of living organisms The decomposers are members of the ecosystem that use dead or decaying organisms as a source of energy As they feed on this organic matter, they further reduce it to its simplest chemical components Decomposers include fungi and bacteria They are also :r:z: :-: ::z:: ::::::::z::: Activity : Draw a food chain using organisms found in your ecosystem 1 -I a- D z / U : :-:-:-r-z o 78

5 Chapter 9 Sc INKS ABçq45 The interaction of many food chains is a food web Most producers and consumers interact with many others, forming a complex food web out of several simple food chains The image below shows more complex food web figure 93 Food Web 1 F Co Co C%4 CO Co LU -I When you think of a predator, do you think of a lion? Or a shark? How about a big, scary grasshopper? Well, a predator is any organism that feeds on other living things The organism it feeds on is its prey So, grasshoppers qualify as predators; their prey is the grass they consume Predator and prey together help maintain an ecological balance within their ecosystem This balance benefits the community as a whole, but can be either helpful or harmful to the individuals that make up the community, depending upon whether they are the predator or the prey I- z > C C C) C i Research a particular ecosystem or biome (ie desert, rainforest or grassland) List all the organisms found in this environment Arrange a food web on poster board using all the organisms Use magazines, drawings or J > 79

6 they : $ ::> J east cosystem nergy IROPHIC LVLS When one organism is consumed by another, its energy transfers as a part of the digestive process Take a look at the energy pyramid in Figure 94 nergy pyramids are a graphical way to show the flow of energy within an ecosystem Notice that the amount of available energy decreases as organisms go up the food chain For this reason, food chains rarely have more than five links A trophic level is the position occupied by an organism in a food chain Organisms that share a trophic level get their energy from the same sources Let s put our producers, consumers and decomposers into the energy pyramid, as in Figure 94 Lose ene rgy (, through KiIIerwhaeI Food contains heat and concentrated I activity I Top \ Wolf ener I iconsumersx a I 4 I \ ; a : dl/ Secondary a 4 / Consumers a Sea ion \Opossum a,f \ r( I Hernny Primary Consumers \Grasshopper st I f I a I \ concentrated r [ Producers / rass energy figure 94 nergy Pyramid Plants are found at the base of the energy pyramid and comprise the first trophic level of the food chain They are called producers Why? They produce their own energy by making their own food (natural sugars) The energy that drives the food making process (remember, photosynthesis?) comes from the Sun Above producers are the primary consumers make up the second trophic level These are the organisms that eat plants, usually, herbivores like deer and grasshoppers Above primary consumers are secondary consumers, which occupy the third trophic level These are organisms that eat primary consumers Finally, there are top consumers also called tertiary consumers They make up thejourth trophic level The Sun has been, and still is, the most influential force on arth At! ofthe energy used by living systems comes from the Sun Think about it: every blade of grass, every squirrel, every fish and every human alive gets the energy needed to live from the Sun F- 8

7 absorbed by the arth s oceans and land surfaces Some solar energy is trapped by living systems (around 1%) Plants like trees and grasses trap solar energy and convert it to chemical energy (glucose) for living systems The plant then uses some chemical energy the Sun s energy is reflected back into space by clouds and the atmosphere, and some is Nuclear reactions in the Sun release energy that travels through space to arth Some of 81 I Maple tree- Bear- Cat- Horse- xamine the list of organisms below Describe each organism s food source Then classify the organisms as autotrophic or heterotrophic Blueberry bush- : Corn- Human- Timothy grassg Wheat- Activity 1%) transfers to the grasshopper Does the grasshopper store all the energy it receives not! nergy is never destroyed It simply changes form It changes from grass to grow, repair injury, maintain homeostasis, move and reproduce ssentially, the plant s tissues (as starches and sugars) When a plant is eaten by a grasshopper, the energy contained in the grass (again around from the plant? NO! Some is used to move, grow and reproduce So, in effect some energy is lost during this energy transfer Is the energy gone or destroyed? Absolutely grasshopper The energy changes from stored chemical energy (glucose) to kinetic energy (organism movement) The plant s energy gives the grasshopper the ability to elephant or a blue whale can grow to such a huge size by eating plant matter It is because plant matter is a concentrated nutritional powerhouse It contains the greatest amount of biologically available energy Now, think about just how far that fast food energy is used to drive life s physical processes of the grasshopper and is dispersed as to survive (ie, grow and reproduce) and some of the energy is stored in the plant s heat The usage of energy in each trophic level means there is less available energy for the next tropic level, because each uses some for survival This is a very important concept You may have wondered how a huge animal like an lunch is from nutritious Think hard Seriously, go get an apple instead Chapter 9

8 cosystem nergy CHAPTR 9 RVIW 1 Animals that eat both plants and other animals are A herbivores B carnivores C omnivores B decomposers 2 The interactions between many food chains is a(n) A food web C abiotic factor B trophic level B ecological balance 3 In a deciduous forest, hundreds of dead leaves fall to the forest floor each autumn Which group of organisms breaks down this tissue for food? A herbivore B omnivore C carnivore B saprophyte 4 What two organisms would be found in the third trophic level? A B C B hawk and human robin and snake dogwood and fox grasshopper and deer 5 The bottom of the energy pyramid is made up of which kind of organisms? a A producers B primary consumers C secondary consumers B top consumers 82