Feeding relationships - WordPress.com · 2010-10-14 · Grade 8 Unit L.5 – Feeding Relationships - 2 - What is an ecosystem? The organisms in their environment interact with the

Grade 8 Unit L.5 – Feeding Relationships

- 1-

Feeding Relationships Curriculum Standards:8.5.1, 8.5.2, 8.5.3

Objectives

1-Define food chain and food web.

2-Compare and contrast habitat and community.

3-Know the factors that affect the population size.

Key Words

Food chain انسالسم انغذائة

Food web انشجكبت انغذائة

Community انجتع

Habitat انىط،ثئة انكبئ انح

Producers انتجبت

Consumers انستههكبت

Predators انكبئبت انفتزسة

Prey انفزسة

Grade 8 Unit L.5 – Feeding Relationships

- 2-

What is an ecosystem?

The organisms in their environment interact with the nonliving parts of the

environment. The organisms also interact with one another. The living and

nonliving things in their environment, together with their interaction, make

up an ecosystem.

Figure 1

The environment is made up of many different ecosystems such as a sea shore, a

forest or a desert. All ecosystems are made up of 2 parts:

1- Non-living parts that make up the habitat like rocks. 2- Living organisms

called the community.

٠زى و ظب . اجحز أ از طاح٠١خ وبصرزى االطبط اج١ئ١خ جػخ خزفخ األظخ اج١ئ١خ

.جشء غ١ز ح اج١ئخ اح١طخ، جشء ح اجزغ اح١: جشئ١ رئ١ظ١

Habitat: is the place where organisms live.

A habitat has the conditions that organisms need to survive and thrive, such as

the right amount of sunlight, water, and food. .٠حز اظزف االئخ ح١بر درجخ حزارح، و١خ بء أوظج١. اج١ئخ اىب اذ ٠ؼ١ش ف١ اىبئ اح

Ecosystem: living and non living things in an environment together with

their interaction. . ج١غ اىبد اح١خ غ١ز اح١خ ف ث١ئخ ؼ١خ اؼاللبد ف١ب ث١ب: اظب اج١ئ

Grade 8 Unit L.5 – Feeding Relationships

- 3-

.

Figure 2

A community: is all the organisms that live in the habitat

Each community is made up of different populations of animals and plants. . و جزغ ػجبرح ػ جػبد اح١ابد اجبد

A population: is a group of organisms of the same species .و جػخ ح٠١خ رزى رجغ األفزاد فض اع

Figure 3: Population of rabbits

Food Chains

Organisms in the environment are related by how they get food. Food chains and

food webs are representations of the predator-prey relationships between

species within an ecosystem or habitat. A predator is an animal that eats

other animals, and the prey is the animal that gets eaten by the predator.

A food chain is a way of demonstrating the food relationships figure 4. Every

organism is part of at least one food chain.

Grade 8 Unit L.5 – Feeding Relationships

- 4-

اظالط اشجىبد .ث١ئخ ااحذح ثؼاللبد غذائ١خ، فى وبئ ٠ض جشء اظالط اغذائ١خرزرجظ ج١غ اىبئبد اح١خ ف اي

.اغذائ١خ رض اؼاللخ ث١ اىبئبد افززطخ افزائض ف ا طظ ث١ئ

Food Chain: Is a visual representation of the food relationships among a

group of organisms in an ecosystem or habitat.

.ف اي ظبو ثئ إلظهبر انعالقبت انغذائة ث يجىعة ي انكبئبت انحة ه وسهة: انسالسم انغذائة

Figure 4

The arrows in food chain in Figure 5 represent the direction that food and

energy move through the food chain.

In the example above grass represents the producer for the chain, the rabbit is

the primary consumer and the fox is the secondary consumer.

.رظز األط ف اظالط اغذائ١خ ارجب ازمبي اغذاء اطبلخ خالي اظظخ

.اظزه اال اضؼت اظزه اضبف اضبي ف االػ ٠ض اؼشت ازج، اب االرت ف

Figure 5

Grade 8 Unit L.5 – Feeding Relationships

- 5-

In Figure 4, the food chain starts with grass. Grass or plants are called

producers because they produce food. Other organisms in the food chain that

are not producers are called consumers. Food and energy flow through the food

chain from the producers to primary consumers to secondary consumers.

اىبئبد اح١ا١خ ف اظالط .رجذأ اظالط اغذائ١خ ػبدح ثبجبربد رظ زجبد ألب رم ثزص١غ غذائب ثفظب

.األ ص اضب ناطبلخ اغذاء ازجبد إ اظزرزم . اغذائ١خ رؼزف ثبظزىبد

Food Web: is a more detailed and complete way of showing food relationships. A

food web shows how a number of food chains are related. Figure 6

Figure 6

أوضز رؼم١ذا رظز و١ف١خ اررجبط أوضز طظخ غذائ١خ غ ثؼضب اجؼط حاشجىبد اغذائ١خ طز٠ك

Producers: organisms that produce their own food by photosynthesis like

plants, algae and some types of bacteria. .اد اطحبت ثؼط ااع اجىز١ز٠بازجبد اىبئبد از غذائب ثفظب ػ طز٠ك ػ١خ اجبء اضئ ض اجبد

Consumers: are an organism that feed on other organisms, they are

herbivores, carnivores or omnivores. اح اظزىبد وبئبد رزغذ ػ غ١زب اىبئبد اح١خ ، اب اوخ اػشبة ا اوخ ح ا رزغذ ػ االػشبة

.

Grade 8 Unit L.5 – Feeding Relationships

- 6-

What causes changes in population size? يب األسجبة انت تؤثز عهى تعذاد األفزاد ف ثئة يعة؟

1. Environmental conditions such as weather can

directly affect population size. A harsh winter or a

bad storm could kill off many plants and animals. On

the other hand, a mild winter or a good summer could

increase the numbers of plants and animals in the

population. أو انعىاصف قذ تسجت تقصب عذد األفزاد ، ثب انغشزاأليطبر : أسجبة ثئة

.انظزوف انالئة قذ تسبعذ ف اسدبد األعذاد 2. Human development can also affect population size. For

example, building roads and houses generally involves

destroying ecosystems and habitats, leaving the

organisms that live there without a home.

.قبو اإلسب ثجبء انجسىر وانجب قذ سجت تذيز أيبك سك ثعض انكبئبت انحة

3. Chemicals can also affect population size. Chemicals may be used on crops

to control weeds and insects. Many organisms are destroyed because they

are viewed as pests. .استخذاو انجذات انحشزة قذ ؤدي ثطزق انخطأ إنى قتم انحىابت

4. Pollution from cars and industry poisons rivers, streams,

and other aquatic ecosystems. This type of pollution does

not just destroy animals and plants that live in the river; it

may also poison any organisms that drink the water or use

the water for other purposes such humans for drinking. انتهىث ي انصبع و انسبرات

5. Predators can also affect population size. A predator is an animal that

hunts for and kills another animal for food. The animal it kills is called

prey. Population sizes of predators and prey are cyclical (cycle). This means

that depending on environmental factors population sizes fluctuate or

change and go through cycles. و انفزائس انفتزسةاختالف عذد انحىابت

Grade 8 Unit L.5 – Feeding Relationships

- 7-

1-What kind of feeding relationship(s) does this picture show?

ما نوع العالقة الغذائة الت تظهر ف الصورة؟

……………………………………………………………………………………………………………………………………………………

2-Look at the above picture to find out the following:

:الصورة السابقة، اكتب اسم كل مما يأتي مباستخدا

a. Producer ____________________________________

b. First Consumer: _________________________________

c. Second Consumer _________________________________

d. 2 food chains:

Grade 8 Unit L.5 – Feeding Relationships

- 8-

3. Complete the following

اكمل الجمل التالية

a. As the number of prey increases the number of predators ……………………….

b. As the number of predators increase the number of prey ………………………..

c. Deforestation ……………………… the population size of the food chain.

4. What are the factors that affect the population size of a food web?

يب ه انعىايم انت تؤثز عهى تعذاد األفزاد ف ثئة يعة؟

a. ________________________________

b. ________________________________

c. ________________________________

d. _________________________________

e. _________________________________

f. _________________________________

Grade 8 Unit L.5 – Feeding Relationships

- 9-

Objectives:

1-Define the pyramid of numbers.

2-Interpret pyramid(s) of numbers and biomass representing

the organisms linked in the food chain.

3-Describe the energy flow through a food chain.

Key Words

Pyramids هزو

Biomass انكتهة انحىة

Toxins انسىو

Pesticides انجذات انحشزة

Grade 8 Unit L.5 – Feeding Relationships

- 10-

Food chains and food webs show the feeding relationships in a community. But

they do not tell us how many living organisms are involved. .رظز اشجىبد اظالط اغذائ١خ اؼاللبد ث١ األفزاد ى ١ض أػذاد األفزاد

Look at the numbers in this food chain

Owl 1

Shrews 10

Caterpillar 100

Oak tree 6000

We can demonstrate this information in a food chain pyramid or a pyramid of

numbers.

Pyramid of numbers: is a way to estimate the number of each species in a food

chain.

.طظخ غذائ١خ أز األػذاد طز٠مخ ؼزض أػذاد األفزاد ف

The area of each box provides an estimate of how many living things there are at

each level. .ػذد األفزاد ف و ظزرمز٠جب رظز ظبحخ و صذق

To build a food chain pyramid you begin with producers on the bottom level, then

the primary consumers on the second level, and so on.

.اضب٠خ ىذاص اظزىبد اال١خ ف. رجذا االزا اغذائ١خ دائب ثبزجبد رى دائب ف االطف

Figure 1: Pyramid of numbers

Grade 8 Unit L.5 – Feeding Relationships

- 11-

How does energy flow through a food chain? كف تتقم انطبقة ف انسالسم انغذائة؟

Generally, as you go up the pyramid there are fewer organisms. This is because

organisms higher up the pyramid are usually bigger than organisms at the lower

levels on the pyramid. It is important to remember that energy is also lost as

it flows along a food chain.

كهب اتقهب كب أ كة انطبقة تقم . فزاد و شذ حجهبألا اتقهب ي األسفم إنى األعهى ف هزو األعذاد تقم أعذاد اكهى

.إنى األعهى ف هزو األعذاد لي األسف

Energy enters a food chain through producers such as grass. The grass stores

the energy; the rabbit eats the grass, taking some of the stored energy into its

body. The rabbit runs around and reproduces both of which use up energy; so

energy is lost. This means there is less energy available to a fox for example who

may eat the rabbit. األػشبة رظزه جشء اطبلخ صذر اطبلخ ف األزا اغذائ١خ اجبربد وبألػشبة، ػذب رزغذ األرات ع

.فمظ جشء ثظ١ظ ٠زم إ اضؼت

Figure 2

Grade 8 Unit L.5 – Feeding Relationships

- 12-

Pyramid of

Numbers

Figure 4 shows a different shaped pyramid of numbers. The pyramid is shown

this shape because of the number of organisms at each level of the food chain.

Although, there is only a single oak tree, it is huge compared with the

caterpillars which feed on it. If you make the size of the levels represent the

mass of the organisms, instead of their numbers, then the pyramid becomes

the right shape again. It is called a Pyramid of Biomass (Figure 5).

اضبي ف االػ. اطزخذا ز اىزخ اح٠١خثؼط أزا األػذاد ال ٠ى ب شى زظ، ف ذ احبالد األفض .Fig4 ٠ظز ز غ١ز زظ

ى ػذ . ف اضبي بن شجزح احذح، رزغذ ػ جػخ اذ٠ذا از رزغذ ػ١ب جػخ ال اط١ر

.Fig5اطزخذا اىزخ اح٠١خ ثذي االػذاد ٠صجح شى از زظ جذ٠ذ وب ف

Figure 3

Figure 4

Figure 5: A Pyramid of Biomass

sBbiomass

Grade 8 Unit L.5 – Feeding Relationships

- 13-

1. What is the pyramid of numbers?

ما هو هرم األعداد؟

2. Represent the following food chains in a pyramid of numbers:

:مثل السالسل الغذائة التالة على شكل هرم اعداد

Oak tree

Oak tree Caterpillar Snake Eagle

Buzzard

Leaves

600 Owl

1

Mouse10

Grasshopper 100

2-

1-

1

- 2

-

Grade 8 Unit L.5 – Feeding Relationships

- 14-

3. Draw a pyramid - in the empty box - of numbers for this food chain, then

answer the following questions: :ارسم هرم األعداد للسلسلة الغذائة التالة ، ثم اجب عن األسئلة الت تلها

a. How many levels أوراق شجرare there in the pyramid?

_________________________________

b. What happens to the number of organisms as you

go up the pyramid?

؟االعداد هرمإلى األعلى ف احدث لعدد األفراد كلما انتقلن ذاما_________________________________

c. What happens to the size of organisms as you go

up levels on the pyramid?

؟االعداد هرمعلى ف ماذا حدث لحجم األفراد كلما انتقلنا إلى األ _________________________________

d. Why are the producers (green plants) always on

the bottom level?

الهرم؟من ف المستوى األول تلماذا توجد المنتجا

______________________________________

______________________________________

100 70

30 5

Grade 8 Unit L.5 – Feeding Relationships

- 15-

4. Define the Pyramid of Biomass?

؟عرف هرم الكتلة الحوة

…………………………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………………….

5. Draw Pyramid of Biomass for the following food chains:

ارسم هرم الكتلة الحوة للشبكة الغذائة التالة؟

7000 g/m2 500g/m2 100g/m2

6. Sketch a pyramid of biomass for the Cornfield/Mice/ Foxes. ارط ز اىزخ اح٠١خ ظظخ اغذائ١خ ازب١خ

Grade 8 Unit L.5 – Feeding Relationships

- 16-

Objective:

Understand why toxins build up or bioaccumulation in the concentration along a

food chain.

Toxins are poisonous chemical substances. Examples are pesticides and

insecticides. .اظ اد و١١بئ١خ ض اج١ذاد احشز٠خ

Pesticides: are chemical substances used by farmers to control pests.

.اشراػ١خ ا٢فبد مز رظزخذ حو١١بئ اد احشز٠خ اج١ذاد

The main farm pests are insects, weeds and moulds.

Without pesticides there would be a large decrease in crop yield. .ا االفبد اشراػ١خ احشزاد االػشبة اضبر اؼف

DDT is a very effective pesticide. Only

small amounts are needed to control or

destroy any organism. DDT is extremely

toxic and does not break down very easily

in our environment or inside the body of

animals either. This means that DDT can be

passed through food chains from the bottom levels all the way to the top levels.

Grade 8 Unit L.5 – Feeding Relationships

- 17-

اج١ذاد ٠DDTؼزجز اي. ح١ش ا و١خ ل١خ رؼزجز وبف١ مز احشزاد, أ اج١ذاد احشز٠خ ٠DDTؼزجز اي

حشز٠خ اخط١زح ح١ش ا ٠جم ٠ززاو فززاد ط٠خ ف اج١ئخ ، اي

.٠زم فزد إ أخز ف اظظخ اغذائ١خ

Take a look at Figure 1, to understand how

DDT is passed through food chains.

DDT was absorbed by the plankton. The

animal plankton feed on the plant plankton.

Figure 1

Fish and other aquatic organisms feed on the animal plankton. Every time a fish

or other aquatic organisms eat animal plankton, they will get a small dose of DDT.

For example, a grebe is a water bird and feeds on many fish. For each fish it

eats, the grebe gets a small dose of DDT. Over time the level of DDT builds up

or bioaccumulates in their bodies and begins to affect the grebe’s health and

may reach lethal levels. This interferes with life processes such as reproduction.

As a result, the grebe population may decline because DDT has bioaacumulated

along the food chain.

إ ظز لبر ف ازم فزد إ أخز ف اظظخ إ أ ص DDTف اضبي اظبثك، ازصذ اجالىزبد اي

.اىبئبد اؼ١ب ف از

Grade 8 Unit L.5 – Feeding Relationships

- 18-

What is Bioaccumulation? Bioaccumulation is the increase in concentration

of a substance in living organisms as they take in

contaminated air, water, or food.

وب اطزىذ ذ ٠شداد رزو١ش ااد اضبرح ف اجظب اىبئبد اح١خ

.اىبئبد اش٠ذ ابء ا ااء ا اغذاء اس

As bigger animals eat smaller animals, the level

of contamination in the food is added to the level

of contamination already in their body.

االصغز ب اسدادد و١خ وب رغذد اىبئبد اىج١زح ػ اىبئبد

.اصبد ف اجظب اىبئبد اىج١زح

رؼزجز ذ اظبز خط١زح ف ابطك اشب١خ ال رزو١ش اصبد اػ

وب ا اجظب اىبئبد اح١خ رحز ػ رزو١ش ػب اذ زجم

. اجظبب دافئخ، ىب رخش و١بد ػب١خ اظ

Figure 2

Grade 8 Unit L.5 – Feeding Relationships

- 19-

1. What are toxins ?

ما ه السموم؟

………………………………………………………………………………………………………

2. Give some examples of toxins.

.اعط مثال على السموم ؟

3. Why do toxins increase in concentration along a food chain? الغذائة؟لماذا زداد تركز السموم على امتداد السالسل

4. How do toxins affect the organisms in the food chain?

كف تؤثر السموم على الكائنات ف السالسل الغذائة ؟

Critical Thinking Challenge:

1. Clear Lake was sprayed with DDT to control insects the DDT affects the

following food chain living in the lake:

على كائنات موجودة في بحيرة DDTتم استخدام ال

a. Which one of the organisms in this food chain first absorbs DDT?

أي الكائنات سوف متص المبدات أوال؟

.......................................................................................................

Grade 8 Unit L.5 – Feeding Relationships

- 20-

b. Which one of the organisms has the highest concentration of DDT?

أي الكائنات سوف تأثر بأعلى تركز من المبدات الحشرة؟

………………………………………………………………………………………………………

c. If your father wants to buy a fish, what will you advise him to buy?

Explain why?

إذا رغب والدك بشراء بعض السمك، بماذا سوف تنصحه أن شتري سمكة كبرة أو سمكة تونا؟ و لماذا؟

………………………………………………………………………………………………………………… …………………………………………………………………………………………………………………

7. What is meant by Bioaccumulation? Explain below.

…………………………………………………………………………………………………………………

………………………………………………………………………………………………………………