KS3 Science

Ecosystems 1Home Learning

Name: _____________________________Class: _____________________________Teacher: ___________________________

In this topic you will learn about:• How living things in an ecosystem depend upon one

another and the factors that effect this

• How plants reproduce and increase the efficiency of

their life cycle

Practical Skills:• Drawing graphs

• Using/ researching source materials

• Using models to understand difficult concepts

This topic has links to:• Ecology– GCSE

Maths in science:

• Interpreting graphs

BBC Bitesize link to this topic: https://www.bbc.co.uk/bitesize/guides/zq4wjxs/revision/1

Working at home:

Try and complete one task on each day when you would have had a science lesson.

Answers are attached at the end of the booklet so that youcan check and mark your work.

Email your science teacher if you are struggling and need something explained.

Email completed work to your science teacher so that theycan check your progress (and give you some achievementpoints!). You can do this by taking a photo of your work and emailing it to them.

Task 1: Food webs

Task 2: Importance of insectsTask 3: InterdependenceTask 4: BioaccumulationTask 5: Pollination

Task 6: Plant ReproductionTask 7: Seed dispersalGlossary

Contents:

2

Task 1: Understanding food webs

Starter: Draw a food chain for the organisms below by putting them in the

correct position in the boxes.

MOUSE SLUG OWL LETTUCE

Learning outcomes:Describe how food webs are made up of a number of food chains.Make predictions about factors affecting plant and animal populations.Analyse and evaluate changes in a food web.

In and On: What do the following key words mean?

- Producer

- Consumer

- Carnivore

- Herbivore

In food chains an organism can be one of the following:

- Producer: The organism that starts the food chain and makes its own food. Usually a plant.

- Primary Consumer: The organism that consumes the producer. Usually a herbivore.

- Secondary Consumer: The organism that consumes a primary consumer.

- Tertiary Consumer: The organism that consumes the secondary consumer. Usually a carnivore. Also called an Apex Predator.

What do the arrows represent in a food chain?

How is energy passed through the food chain?

Most animals eat many different things and are involved in many different food chains. Food chains can be linked together in a food web, which shows how the food chains are connected. Food webs can be complex.

Try and put the following organisms into the food web diagram on the next page:

• Algae (Producer)• Human (Apex Predator)• Pike (Tertiary Consumer)• Eels (Secondary Consumer)• Caddis Fly larvae (Primary Consumer)• Shrimp (Secondary Consumer)• Water flea (Primary Consumer)• Young Fish (Secondary Consumer)• Carp (Apex Predator)• Cyclops (Primary Consumer)• Trout (Tertiary Consumer)

In the food chain below, what is the:

1. Producer

2. Primary consumer

3. Apex predator

4. Secondary consumer

Food web task

Check the answer at the back of the booklet and make any corrections on the diagram below.

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Analyse and evaluate the impact on the food web if:

All the fish were killed

House owners fertilised their lawns and then it rained

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Task 2: The importance of insects

In and On:

Learning outcomes:Describe the impact of low pollination on crop production.Explain why artificial pollination is used for some crops.Evaluate the risks of monoculture on world food security.

Watch the video: https://www.youtube.com/watch?v=JilYBVrFiLA&t=2sYouTube = What happens if all the bees die?Write down three key points from the video:

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Why do fruit growers put beehives in their orchards?

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Fruit Production and BeesBees are vital in pollinating fruit crops. Pollination is successful when flowers receive healthy pollen at the best time. The better the pollination of apples and pears, the more numerous and larger the fruits.

Anything that interferes with bee activity, such as disease or adverse weather, will reduce pollination. Bee colony numbers in Britain have fallen dramatically which has lowered fruit yields. This results in a higher cost of apples in the shops.

Read the passage regarding the importance of insects and answer the questions in your booklets.

1. What is the PREDICTION for the demand in food supply in the next 40 years?

2. What does BIODIVERSITY mean?

3. What is POLLINATION?

4. Name 5 foods that depend on insect pollination.

5. What has happened to the honeybee and why? Use figures in your answer.

6. Explain why cows depend on insects.

7. What are the suggestions to replace pollination by insects?

8. Why would this not really work?

9. How is the UK government trying to protect bees?

Comprehension task: Read the passage regarding the importance of insects and

answer the questions in your booklets

The demand for food production will double in the next forty years. This raises serious concerns about food security - how will we produce enough food to feed ourselves in the future? Biodiversity is when there is a wide range of plants and animals in a habitat, and within this is a wide range of insects which make sure our crops grow well and remain healthy. For instance, 8 out of ten European crops depend on pollination by insects. Pollination is when the pollen from a male plant fertilises the female plant to create a seed. Most of these pollinators are bees, including honeybees and a wide range of wild bees such bumblebees, as well as hoverflies. Without bees transferring pollen most of our crops could not produce seeds and fruits.

Our diets are full of foods which depend on bee pollination. Breakfast examples are: Orange juice, fresh fruits, jam, marmalade, fruits in our yoghurts - these all rely on pollinators. As does coffee which is pollinated by bees in the tropics. Chocolate, which comes from cocoa, relies on a tiny midge to pollinate it. Even meat and dairy products partially depend on the work of pollinators, as part of the diet of many cattle relies on insect pollinated plants such as clover. Our bees and other pollinators are not about to totally disappear but they are under great threat. For instance, the UK has an amazing variety of bees with more than 250 species. However, recent research has shown that since 1980 the diversity of bees has severely declined. The honeybee has declined by 54% in England since 1985. The reasons are destruction of bee habitats, pests, diseases, and misuse of pesticides.So what can farmers do about this problem? One way would be to try and replace insects. So instead of bees we could use people to hand pollinate crops. This is already used in parts of China and Nepal for apples. However, to cover the cost of labour and equipment to pollinate all our crops in the UK would cost £1.5 billion a year! This is so expensive that it would make the price of these food products too high. Thankfully there is another way to ensure our own food security. We can protect and conserve our British bees and keep them working to pollinate our crops. Our honeybees are being supported by the government's 'Healthy bee plan'. However, relying on a single bee species to do the job is risky as if a disease hits we lose them all. The answer is to try to maintain a wide range of different species of bee (biodiversity).

We know that wild bees, honeybees, butterflies and many other species such as birds greatly benefit from flower rich habitats. Farmers can easily add these habitats to the landscape around the edges of fields and many farmers already do this. The government pays the farmers to do this.

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Tackling food security.

Where single crops are grown in vast fields is called monoculture. Insects such as

bees cannot survive naturally in these areas because the flowering time is too short

and there are no other plants for them to feed on.

Some poor countries use monoculture to grow huge quantities of crops that they sell

to richer countries, such as coffee, cocoa and bananas. Little fertile land is left to

grow food crops for the local people who then suffer food insecurity.

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Task:Watch the following videos and answer the following questions in your booklet:

Monoculture: https://www.youtube.com/watch?v=VH_wt8xBrm4Food Security https://www.youtube.com/watch?v=VCYeLuURxRM1. What is food security.2. What are the advantages of monoculture.3. What are the disadvantages of monoculture

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Task 3: Interdependence

In and On:Create a food chain which contains a producer and two consumers. For each organism, label it as producer or consumer.

Learning outcomes:

• Describe ways in which organisms affect their environment.• Research and prevent findings about the impact of one organism

Symbiotic relationships

Symbiosis means living together. Symbiotic relationships are close or intimate relationships between members of two different species.Symbiotic relationships usually benefit at least one of the individuals involved.There are three categories of symbiosis.Research and write a definition of what each one means:

• Parasitism –

• Mutualism –

• Commensalism –

Watch the video on Animal Partnerships (BBC Wildlife David Attenborough) on YouTube: https://www.youtube.com/watch?v=Qqa0OPbdvjw

Why is this a mutualistic relationship?

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Mutualistic relationship: Look on YouTube for videos of the Oxpecker bird

Parasitic relationship: Look on YouTube for videos of the Crown of Thorns Starfish

Parasitic relationship: Another example

Ticks are a parasite of humans. They are vectors for Lyme’s disease and therefore can cause severe damage to the host whilst feeding on their blood.

Why is this a parasitic relationship?

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Q1. How does the population of snowshoe hare affect lynx population

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__________________________________________________________Q2. Explain this relationship.

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__________________________________________________________Q3. Why does the lynx population drop significantly around 1870?

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Predator-Prey relationships

Task 4 – Bioaccumulation

In and On: Correct the spelling and punctuation mistakes from the passage below

Their are three relationships that ecsist between organisms. These are mutuelism, parasitism

and comensalism.

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Learning Outcomes:• Describe how toxins pass along the food chain.• Explain how toxins enter and accumulate in food chains.• Evaluate the advantages and disadvantages of using pesticides.

BioaccumulationA pesticide called DDT was used in the 1960’s but was banned worldwide in 2001 because of its effect on the environment. Watch the video below and write a definition of the term: bioaccumulation

https://www.youtube.com/watch?v=ynMgY8CZn6o

https://www.youtube.com/watch?v=TZk6vcmLcKw (Longer explanation)

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The problems with pesticides

Watch the following video and complete the following tasks:https://study.com/academy/lesson/use-of-pesticides-benefits-and-problems-associated-with-pesticides.html

Define what a pesticide is:

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Advantages Disadvantages

Watch this video and complete your table to state the advantages and disadvantages of pesticide use in agriculture.

https://www.youtube.com/watch?v=fotJOREWuRE

Task: Speech writingYou are to write a speech you could deliver to a conference of experts regarding the use of pesticides. In your speech you should include:• What pesticides are and any examples you have learned of.• The advantages of their use.• The disadvantages of their use.• A justified conclusion based on your opinion.

You will be judged on the quality of your writing.

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Task 5 – PollinationIn & On: Come up with as many words as you can linked to the structure of flowers

Learning Outcomes:• Identify parts of flowering plants.• Describe the function of the parts of flowering plants and link structure and function.• Evaluate the differences between wind-pollinated and insect-pollinated plants.

Label the parts of the flowering plant. Use the video to help you.https://www.youtube.com/watch?v=djPVgip_bdU

Structure Function

The male part of the plant, consisting of anther and

filament

Produces pollen, the male sex cell

Brightly coloured to attract insects

Protects the developing flower

The female part of the plant, consisting of the stigma,

style and ovary

Sticky top to trap pollen

Contains ovules, the female sex cell

Task: What is Pollen? What is it’s function in plants?

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Challenge: Which organ does pollen come from?

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Complete the table to match the structure with its function in the flower:

Task: Google ‘wind pollinated flowers’ and ‘insect pollinated flowers’ Look at the Google images of both types of flowers. Note down any differences that you can see between them on the table below.(Hint: Look for differences in petals, stamen, carpel, stigma)

Insect-pollinated Wind-pollinated

Wind pollinatedInsect pollinated

How are flowers adapted?

a. Explain the importance of the position of the stamen in relation to the stigma in insect-pollinated flowers

b. Explain the position of the anther and filament in wind-pollinated flowers

c. Explain the advantages and disadvantages of each type of pollination

Wind or insect-pollinated plants?Look at the different plants. Categorise them as either wind-pollinated or insect-pollinated. Explain the reasons for your choices.

Task 6 – Fertilisation

In & On: Are these pollen grains from wind pollinated or insect pollinated flowers?

Challenge: What features are you looking for?

Learning Outcomes:• Describe the processes of fertilisation in plants.• Describe the role of pollen tubes• Explain how seeds are formed

Label the structures

For fertilisation to occur, the ovule and the pollen cell must meet.As the pollen sits on the stigma, a pollen tube grows out of the pollen grain through the stigma and style and down into the ovary.

The nucleus of the pollen cell travels down the tube into the ovary and meets the nucleus of the ovule; this is fertilisation.

This fertilised ovule will eventually develop into a new plant.

Watch: https://www.youtube.com/watch?v=2ycl2E9r-_o (from 4.50)

Development of seeds

Lesson 7 –Seed dispersal

In & On:: How are these seeds dispersed?

Learning Outcomes:

Recognise the variety of different structures shown by different seeds.Describe the need for plants to disperse their seed.Plan an investigation into seed dispersal by wind.Collect data and devise questions on how plants can effectively disperse seeds.

Challenge: Can you name the plant these seeds come from?

What does seed dispersal mean?

Why are seeds dispersed?

Why is seed dispersal important?

Watch the video about seed dispersal and answer the questions below: https://www.youtube.com/watch?v=BV8uNz5iwGU

Name some ways that seeds can be dispersed.

Method Explanation Example

Water

Wind

Animal: fruit

Animal: sticky

Explosion

Adaptations of seedsUse the internet to research these different methods of seed dispersal. For each one, explain how the seeds are moved away from the plant, and give an example of a plant that uses this method.

40Glossary

Key term Definition

Bioaccumulation Increase in the concentration of a chemical as it is passed on

from one organism to another up a food chain

Competition Struggle between different organisms for survival

Consumer Animal that eats other animals or plants

Decomposer Organism that breaks down dead plant or animal tissue

Dispersal Distribution over an area (for example, of the seed away from

the parent plant)

Ecology Study of the interactions between organisms and their

environment

Ecosystem The living things in a given area and their non-living

environment

FertilisationWhen the nucleus of a male sex cell fuses (joins with) that of a

female sex cell

FertiliserChemical put on soil to increase soil fertility and allow better

growth of crop plants

FertiliserChemical put on soil to increase soil fertility and allow better

growth of crop plants

Food webFlow diagram showing how a number of living things in a

habitat get their food

Germination When a seed begins to grow into a plant

Interdependence

Mutual reliance between two or more groups. In an

ecosystem populations of different organisms may affect each

other

ModelSomething which explains an aspect or part of the physical

world

Monoculture Growing of a single crop in an area

PollinationProcess of transferring pollen from the anther of a flower to the

stigma of another flower

Task 1 – Understanding Food Webs

In and On: What do the following key words mean?- ProducerAn organism that makes its own food- ConsumerAn organisms that consumes another for food.- CarnivoreAn organism that eats only meat- HerbivoreAn organism that eats only plants

Starter: Draw a food chain for the organisms below by putting them in the

correct position in the boxes.

MOUSE SLUG OWL LETTUCE

Lettuce Slug Mouse Owl

In the food chain below, what is the:

1. Producer = phytoplankton

2. Primary consumer = Krill

3. Apex predator = seal

4. Secondary consumer = arctic cod

What do the arrows represent in a food chain?

The transfer of energy

How is energy passed through the food chain?

Phytoplankton captures the energy from sunlight to photosynthesise

and make glucose providing energy for growth.

Krill eats the phytoplankton, the arctic cod eats the krill, and the seal

eats the arctic cod.

If all the fish were killed –Shrimp, water fleas and eels all increase, so cyclops, algae and caddis fly larvae decrease; only eels are left as food for humans

If house owners fertilised their lawns and then it rained –Algae increase dramatically; primary consumers increase

If the weather became warmer and less rain fell –Water levels reduced, so less oxygen available, and larger fish die; invertebrates decrease

If all the water fleas died –Young fish/shrimp decrease; more algae grow, increasing caddis fly and cyclops; shrimp and young fish then start to increase slowly

If there was an oil spill –Fish gills block, so the fish cannot get the oxygen needed for respiration and die; less oxygen will diffuse into the water at the surface; invertebrates may survive better because they have a short life-span and reproduce quickly.

If a new species of fish was introduced –The carp will decrease rapidly, because roach eat shrimp, carp’s only food source, meaning less food is available for the carp.

Task 2 – Importance of Insects

Comprehension Task: Why insects are important•What is the PREDICTION for the demand in food supply in the next 40 years?The demand for food production will double•What does BIODIVERSITY mean?When there is a range of plants and animals in a habitat•What is POLLINATION?When the pollen from a male plant fertilises the female plant to create a seed•Name 5 foods that depend on insect pollination.Orange juice, fresh fruits, jam, marmalade, fruits in our yoghurts, coffee, chocolate, meat and dairy products•What has happened to the honeybee and why? Use figures in your answer.The honeybee has declined by 54% in England since 1985. The reasons are destruction of bee habitats, pests, diseases, and misuse of pesticides.•Explain why cows depend on insects.Part of the diet of many cattle relies on insect pollinated plants such as clover.

•What are the suggestions to replace pollination by insects?We could use people to hand pollinate crops. This is already used in parts of China and Nepal for apples.

•Why would this not really work?To cover the cost of labour and equipment to pollinate all our crops in the UK would cost £1.5 billion a year! This is so expensive that it would make the price of these food products too high.

•How is the UK government trying to protect bees'Healthy bee plan‘ - protect and conserve our British bees and keep them working to pollinate our crops, to try to maintain a wide range of different species of bee (biodiversity).

Video questions1. What is food security?Food security is when all people at all times have access to enough food to meet their dietary needs and food preferences.2. What are the advantages of monoculture?More efficient- You can grow more crops in less time.Quicker harvests.You can use the same resources for each crop.3. What are the disadvantages of monoculture?Lack of diversity can lead to inability to survive disease.Less time of the year for insects to pollinate or feed.Cost and effort to diversify crops.

Task 3 – Interdependence

There are three categories of symbiosis:Parasitism – one species, the parasite, benefits at the expense of the other species, the host.Mutualism – both species benefit from the relationship.Commensalism – one benefits, the other is not harmed but doesn’t benefit

Why is this a mutualistic relationship?

The oxpecker bird cleans small insects off the back of many animals in Africa

including hippos. Both species benefit from the relationship.

Mutualistic relationship: Look on YouTube for videos of the Oxpecker bird

Parasitic relationship: Look on YouTube for videos of the Crown of Thorns Starfish

Why is this a parasitic relationship?

The crown of thorns starfish feeds on coral polyps destroying whole regions of

coral reefs. The starfish benefits at the expense of the coral which is harmed.

Predator Prey relationships: Answers 1. As the population of Snowshoe hares increases, the population of lynxes

increases after a short delay.

2. When there are more hare’s, there is more food for the lynx to eat, therefore more survive and reproduce.

3. When the population of hare’s is low, the population of lynxes will drop because they haven’t got enough prey to support a large population.

Task 4: Bioaccumulation

In and On: Correct the spelling and punctuation mistakes from the passage below

Their are three relationships that ecsist between organisms. These are mutuelism, parasitism and comensalism.

ANSWERThere are three relationships that exist between organisms. These are mutualism, parasitism and commensalism.

How do toxins enter the food chain?:•How do poisons get into the ocean and wetlands?

Run off from fields/ loss of cargo/ rivers•How do the poisons get into an animal?

From food eaten or water drunk•Do you think that the poisons stay in the body of the animal or do they leave?

Mostly stay in the body•What do you think happens to the poisons in a small animal when it is eaten by a bigger animal?

Poison is absorbed into the bigger animal

Task: Use the information in the video and the diagram to define and explain the term bioaccumulation.At the start of the food chain, the producer will absorb a small amount of the toxin. Primary consumers eat the toxin in the plant, which causes an increase in concentration. The concentration of the toxin increases as it is passed up the food chain, where it reaches deadly levels.

1. Define what a pesticide isA pesticide is a chemical that is used to prevent pest species from eating a crop or plant that we grow agriculturally.

Advantages Disadvantages

Better crop yields therefore make more food.

Can move to other areas not intended.

More profit made Water contamination due to it going intothe land

Direct benefits to human health by killing pests that carry diseases.

Genetic resistance which makes the chemical useless.

Increases food security Can change existing food chains by killing other species

Task 5: Pollination

Labelling the parts of a flowing plant:

Functions of the parts of a flowing plant:• Stamen – the male part of the plant, consisting of anther and

filament

• Anther – produces pollen, the male sex cell

• Petal – brightly coloured to attract insects

• Sepal – protects the developing flower

• Carpel – the female part of the plant, consisting of the stigma, style and ovary

• Stigma – sticky top to trap pollen

• Ovary – contains ovules, the female sex cell

Task: What is pollen? What is its function in plants?It is the male sex cell in plant reproduction. Its job is to fertilise the egg.It is produced by the anthers.

How are flowers adapted?a)Explain the importance of the position of the stamen in relation to the stigma in insect-pollinated flowers So that pollen can be collected when insects gather nectar.

b) Explain the position of the anther and filament in wind- pollinated flowers. Outside of the flower so that the pollen can be effectively removed by the wind

c) Explain the advantages and disadvantages of each type of pollination.Wind pollinatedNo guarantee the wind will transfer pollen from one plant to the next – millions of pollen grainsQuicker process of reproduction and little energy wasted on nectar Insect pollinatedA longer process and some insects eat parts of the flower or plant so mechanisms to avoid this have been developedPollination is not weather dependent and pollen is taken directly to another plant so far less pollen is needed

wind wind

wind

insect

insect insect

Task 6: Fertilisation

In & On: Are these pollen grains from wind pollinated or insect pollinated flowers?

Challenge: What features are you looking for?

insect wind wind insect

What is the definition of a fruit?An ovary after fertilisation, containing seeds

Why are pea pods and tomatoes fruits even though they are often called vegetables?They contain seeds, vegetables don’t

Task 7: Seed Dispersal

What does seed dispersal mean?

Why are seeds dispersed?

Why is seed dispersal important?

Name some ways that seeds can be dispersed.

Seed dispersal is when seeds are transported from the plant to another area in order to grow.

Seeds need to be dispersed as far away from the parent plant as possibleAway from the parent plant there would be more light, nutrients and water

This increases the chance of successful growth.

Water, wind, animals, explosion