LESSONFOOD CHAIN

FOOD CHAINEvery organism needs to

obtain energy in order to live. For example, plants get energy from the sun, some animals eat plants, and some animals eat other animals.

FOOD CHAINA food chain is the sequence

of who eats whom in a biological community an ecosystem to obtain nutrition. A food chain starts with the primary energy source, usually the sun or boiling-hot deep sea vents.

PRODUCERProducers organisms that

make their own food from sunlight and chemical energy from deep sea vents are the base of every food chain - these organisms are called autotrophs.

CONSUMER• Primary consumers are animals that

eat primary producers; they are also called herbivores (plant-eaters.

• Secondary consumers eat primary consumers. They are carnivores meat-eaters and omnivores animals that eat both animals and plants.

• Tertiary consumers eat secondary consumers.

• Quaternary consumers eat tertiary consumers.

• Food chains "end" with top predators, animals that have little or no natural enemies.

HERBIVORES

HERBIVORESA herbivore is an animal

 anatomically and physiologically adapted to eating plant material, for example foliage, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthparts adapted to rasping or grinding.Horses and other herbivores have wide flat teeth that are adapted to grinding grass, tree bark, and other tough plant material.

OMNIVORES

OMNIVORESAn omnivore is a kind of animal

that eats either other animals or plants. Some omnivores will hunt and eat their food, like carnivores, eating herbivores and other omnivores. Some others are scavengers and will eat dead matter. Many will eat eggs from other animals.

CARNIVORES

CARNIVORESA carnivore  meaning meat eater. meat

or flesh and vorare meaning to devour is anorganism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging.  Animals that depend solely on animal flesh for their nutrient requirements are called obligate carnivores while those that also consume non-animal food are called facultative .

QUESTIONS

Write true or false.

____1.Carnivores eat plants only.____2.Omnivorse eat meats only.____3.Herbivores eat both flesh

plants and meat.____4.Worm is example of

herbivores.____5.Producer depends on

consumer.

Write O if omnivores C if carnivorse and H if

herbivores

___1.eat flesh meats.

____2. eat flesh plants.

____3.eat both flesh meats and

plants.

LESSONFOOD WEB

FOOD WEBA food web (or food cycle) is the natural

interconnection of food chains and generally a graphical representation (usually an image) of what-eats-what in an ecological community. Another name for food web is a consumer-resource system. Ecologists can broadly lump all life forms into one of two categories called trophic levels: 1) the autotrophs, and 2) the heterotrophs. To maintain their bodies, grow, develop, and to reproduce, autotrophs produce organic matter from inorganic substances, including both minerals and gases such as carbon dioxide. These chemical reactions require energy, which mainly comes from the sunand largely by photosynthesis, although a very small amount comes from hydrothermal vents and hot springs.

FOOD WEBA gradient exists between trophic

levels running from complete autotrophs that obtain their sole source of carbon from the atmosphere, to mixotrophs (such as carnivorous plants) that are autotrophic organisms that partially obtain organic matter from sources other than the atmosphere, and complete heterotrophs that must feed to obtain organic matter.

FOODWEBThe linkages in a food web

illustrate the feeding pathways, such as where heterotrophs obtain organic matter by feeding on autotrophs and other heterotrophs. The food web is a simplified illustration of the various methods of feeding that links an ecosystem into a unified system of exchange.

FOOD WEBThere are different kinds of feeding

relations that can be roughly divided into herbivory, carnivory, scavenging and parasitism. Some of the organic matter eaten by heterotrophs, such as sugars, provides energy. Autotrophs and heterotrophs come in all sizes, from microscopic to many tonnes - from cyanobacteria to giant redwoods, and from viruses and bdellovibrio to blue whales.

QUESTIONS

Answer the questions below.____1. Who is the producer.____2 .Who is the consumer ____3. Who is the 2nd consumer.____4. Who is the third consumer. ____5.How many can you make from the picture.

LESSONTHE ENERGY PYRAMID

THE ENERGY PYRAMID• What is an energy pyramid• Energy pyramid• An energy pyramid is a

graphical model of energy flow in a community. The different levels represent different groups of organisms that might compose a food chain. From the bottom-up, they are as follows:

THE ENERGY PYRAMIDProducers — bring energy from nonliving

sources into the communityPrimary consumers — eat the

producers, which makes them herbivores in most communities

Secondary consumers — eat the primary consumers, which makes them carnivores

Tertiary consumers — eat the secondary consumers

In some food chains, there is a fourth consumer level, and rarely, a fifth. Have you ever wondered why there are limits to the lengths of food chains?

Why are energy pyramids shaped the way they are?

An energy pyramid’s shape shows how the amount of useful energy that enters each level — chemical energy in the form of food — decreases as it is used by the organisms in that level. How does this happen?

Why are energy pyramids shaped the way they are?

Recall that cell respiration “burns” food to release its energy, and in doing so, produces ATP, which carries some of the energy as well as heat, which carries the rest. ATP is then used to fuel countless life processes.

THE ENERGY PYRAMID

The consequence is that even though a lot of energy may be taken in at any level, the energy that ends up being stored there – which is the food available to the next level — is far less. Scientists have calculated that an average of 90% of the energy entering each step of the food chain is “lost” this way (although the total amount in the system remains unchanged).

THE ENERY PYRAMID

The consumers at the top of a food pyramid, as a group, thus have much less energy available to support them than those closer to the bottom. That’s why their numbers are relatively few in most communities. Eventually, the amount of useful energy left can’t support another level. That’s why energy flow is depicted in the shape of a pyramid. The energy that enters a community is ultimately lost to the living world as heat.

BRAIN DRILL

CHOOSE THE LETTER OF THE CORRECT

ANSWERWho bring the energy from non-living

sources into the community?a. Consumer b. Producer c. DecomposerScientists have calculated that an average

of ____ of the energy entering each step of the food chain is ____ this way

a.40% lost b. 60% found c. 90% lost

LESSONTHE NUTRIENT CYCLE

THE NUTRIENT CYCLES

A nutrient cycle or ecological recycling is the movement and exchange of organic and in organic matter back into the production of living matter. The process is regulated by food web pathways that decompose matter into mineral nutrients. Nutrient cycles occur within ecosystems.

THE NUTRIENT CYCLES

The process is regulated by food web pathways that decomposematter into mineral nutrients. Nutrient cycles occur within ecosystems.

THE NUTRIENT CYCLESEcosystems are interconnected

systems where matter and energy flows and is exchanged as organisms feed, digest, and migrate about. Minerals and nutrients accumulate in varied densities and uneven configurations across the planet.

THE NUTRIENT CYCLESEcosystems recycle locally,

converting mineral nutrients into the production of biomass, and on a larger scale they participate in a global system of inputs and outputs where matter is exchanged and transported through a larger system ofbiogeochemical cycles.

THE NUTRIENT CYCLESThe nutrient cycle is nature's recycling system.

All forms of recycling have feedback loops that use energy in the process of putting material resources back into use. Recycling in ecology is regulated to a large extent during the process of decomposition.[2] Ecosystems employ biodiversity in the food webs that recycle natural materials, such as mineral nutrients, which includes water. Recycling in natural systems is one of the many ecosystem services that sustain and contribute to the well-being of human societies.

THE NUTRIENT CYCLESThere is much overlap between the terms for 

biogeochemical cycle and nutrient cycle. Most textbooks integrate the two and seem to treat them as synonymous terms. However, the terms often appear independently. Nutrient cycle is more often used in direct reference to the idea of an intra-system cycle, where an ecosystem functions as a unit. From a practical point it does not make sense to assess a terrestrial ecosystem by considering the full column of air above it as well as the great depths of Earth below it. While an ecosystem often has no clear boundary, as a working model it is practical to consider the functional community where the bulk of matter and energy transfer occurs.

BRAIN EXERCISE

FILL THE BLANK CHOOSE THE CORRECT ANSWER

Ecosystems are _______systems where _____and _____flows and is exchanged as organisms feed, digest, and migrate about. ______and nutrients accumulate in varied ________and uneven configurations across the planet.

Matter Interconnected Energy Densities Minerals

LESSON OXYGEN AND CARBON CYCLES

OXYGEN AND CARBON CYCLESWe usually refer to the cycling of carbon and oxygen in our

atmosphere together because of how they are extremely interconnected.

 With the exception of certain bacteria all animals,

including aquatic, animals need oxygen to survive. Even though our bodies are 80% water, Carbon is the most

abundant element our bodies.  It is carbon that combines to produce sugars necessary for energy.

 A cycle is a constant chain of events; there is no beginning and no

end. A Process is a series of steps involves in creating something. 

OXYGEN AND CARBON CYCLES

The Carbon/Oxygen Cycle involves three major processes and one minor process: photosynthesis, respiration, combustion and decomposition

OXYGEN AND CARBON CYCLES

• Photosynthesis:–  Green plants/trees take in Carbon

Dioxide and water using the chlorophyll in their leaves and energy from the sun they release Oxygen, sugar and water vapor.

– The chemical formula for photosynthesis is:

– C02+H02+SUNs ENERGY+chlorophyll

OXYGEN AND CARBON CYCLES

• Like most living things, you need oxygen to survive.

• The atmosphere, which is 20 percent oxygen, supplies you and other air-breathing organisms with this vital gas.

• Oxygen from the atmosphere that has dissolved in water is breathed by fish and other aquatic organisms.

• Clearly, living things would have used up the available oxygen supply in the atmosphere millions of years ago if something did not return the oxygen to the air.

• But what could that something be? 

OXYGEN AND CARBON CYCLES

• Consider this: • When you inhale, you take in oxygen.• When you exhale, you release the waste

gas carbon dioxide.• If something used carbon dioxide and

released oxygen, it would balance your use of oxygen.

• That something is producers such as green plants and certain microorganisms.

OXYGEN AND CARBON CYCLES• These producers use carbon dioxide gas,

water, and the energy of sunlight to make carbon containing compounds that are often referred to as "food."

• During the food making process, the producers also produce oxygen, which is released into the environment.

• Through this process, known as the oxygen cycle, there is always a plentiful supply of oxygen available for air-breathing organisms.

BUT WHAT HAPPENS TO THE CARBON IN FOOD?

In order to extract energy from food, organisms must digest the food, or break it down into simpler substances.

Energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism through food webs.

How is it transformed back into carbon

This process ultimately produces water and carbon dioxide, which are released back into the environment.

BRAIN EXERCISE

FILL THE BLANKS. CHOOSE THE CORRECT ANSWER

The _______/Oxygen Cycle ______three major _______ and one minor process: ________respiration, combustion and ________.

Involves Photosynthesis Processes Decomposition Carbon

LESSONRELATIONSHIP BETWEEN ORGANISM AND ECOSYSTEM

THE RELATIONSHIP BETWEEN ORGANISYMS AND ECOSYSTEM• Abiotic vs. Biotic Components• Ecosystem Roles and Energy Flow thr

ough Ecosystems• Population Dynamics• Niches• Energy Flow• The Effect of Populations on Ecosyst

ems

Biotic v.s. biotic components.• Abiotic components of ecosystems are those that are non-living.

These include:– amount of water present,– nutrient and mineral availability,– soil structure and substrate,– climate,– amount of sunlight available.

• Biotic components of ecosystems are those that are living or were previously living.

• The biotic and abiotic components shape how species have adapted over time, and what species can exist in any given ecosystem.

• Matter can alternate between the abiotic and biotic environment in cycles. For example, carbon can be incorporated as sugar in a plant (biotic), but can later be released into the atmosphere after it is consumed in the form of carbon dioxide (abiotic).

Ecosystem roles and energy flows

• The three main ecosystem roles an organism can occupy are producers, consumers, and decomposers.

• Producers can synthesize sugars for energy from an abiotic source in processes such as the following.– Photosynthesis in plants and algae, where the

energy in sunlight is absorbed and transformed into the chemical bonds of sugar.

– Chemosynthesis in deep ocean bacteria, where the oxidation of inorganic compounds exuded from hydrothermal vents act as an energy source. This is done in the absence of light.

Ecosystem roles and energy flows

• Consumers rely on the consumption of other organisms as a source of organic compounds, other nutrients, and energy– Herbivores, organisms which consume only plants,

are known as primary consumers.– Carnivores, organisms which predate on (“eat”)

other animals, are known as higher level consumers (secondary, tertiary, quaternary, etc).

• Decomposers obtain energy and organic compounds from decaying dead organisms, recycling nutrients (mainly nitrogen and phosphorus) back to producers in the process.

POPULATION DYNAMICS• The size and growth of a population depends on the rates

of births, deaths, immigration and emigration. If a population’s size is constant, these rates are in a state of dynamic equilibrium.

• Factors that affect birth and death rates (and therefore population growth) can be dependent on or independent of population density (the number individuals in an amount of space).

• Density dependent factors lead to repeating cycles in population size.

• Principles of population ecology are used extensively in the management of wildlife. Hunting seasons, catch limits, size restrictions, and quotas used for fish, seafood, and game are all ways in which governments of the world promote healthy and sustainable population sizes for these organisms.

NICHES• Niche represents the sum total of all the ways it

utilizes resources in its environment: its habitat, diet, time of activity, method and time of reproduction, space utiization, and other factors.

• If two species share the same or a similar niche, they will both compete for the same resources and the worst competitor will be driven to extinction (in that area). This is called competitive exclusion.

• Habitats that are more complex (in food sources, prey refuges, soil substrates, etc.) have more potentially available niches, and therefore tend to have higher diversity of species of organisms.

ENERGY FLOWS• Ecosystems include autotrophs (organisms, such as

plants, that manufacture their own food from external sources of energy) and heterotrophs (consumers, such as animals, fungi and many protists).

• Once energy enters an ecosystem, it is passed from one organism to another by ingestion (as food) or decomposition.

• Primary producers convert light energy or, rarely energy from chemosynthesis, into chemical bonds.

• Consumers rely on producers for their energy sources.

• All food chains begin with producers, followed by primary consumers, secondary consumers and tertiary consumers.

The effect of population on ecosystem

• Species can affect one another and ecosystems in a variety of ways.

• Communities tend to become more complex over time. This process, known as succession, leads to changes in soil, and the populations of organisms that are present.

• Primary succession takes place when organisms gradually inhabit a bare substrate (such as rock), leading to the development of soil and gradual increases in the numbers of kinds and species. Over time, as conditions change, different groups of organisms become prevalent.

• Secondary succession occurs in an area where a disturbance, such as fire, has occurred.

The effect of population on ecosystem

• In general, early stages of succession are characterized by fast-growing (or weedy) species that tolerate extreme conditions, known as r-selected species. Gradually, these early invaders are replaced by other species (K-selected species) that compete more effectively in the environment that has been colonized (and changed) by the weedy colonizers.

• Invasive species are those that are introduced into a new habitat, where they out compete native species that share similar niches. Invasive species can have drastic effects on biodiversity and energy flow in communities.

QUESTIONS

ANSWER THE FOLLOWING QUESTIONS

1. What is the abiotic component?2. What is the biotic component?3. What is the three ecosystem roles?4. How does the population effect the

ecosystem?5. What is autotrophs