MODULE mod7A mod7B mod7C mod7D mod7E mod7F mod7G mod7H mod7I mod7J mod7K mod7L mod8A mod8B mod8C mod8D mod8E mod8F mod8G mod8H mod8I mod8J mod8K mod8L mod9A mod9B mod9C mod9D mod9E mod9F mod9G mod9H mod9I mod9J mod9K mod9L 8da1
8Da1 Water loss
Name _____________________________ Class ____________
You are going to find out which leaf loses the least water.
Apparatus
- Selection of leaves - 2 clamp stands
- String - Thread
- Stopclock - Balance
Method
1 Take a fresh leaf from each plant.
2 Measure the mass of each leaf on a balance, and write its mass in the results table on the next page.
3 Hang your leaves up in a warm place to dry.
4 After 30 minutes measure the masses of all your leaves again and record the results.
Prediction
What leaves will you use? _________________________________________________________
Which leaf do you think will lose the least water? _______________________________________
Which leaf do you think will lose the most water? _______________________________________
Why do you think this ____________________________________________________________
_______________________________________________________________________________
Recording your results
Leaf
Mass at start (g)
Mass after drying (g)
Mass of water lost (g)
Considering your results/conclusions
Which leaf lost the least water? _____________________________________________________
Which leaf lost the most water? _____________________________________________________
Was your prediction right? _________________________________________________________
If not, explain what you think now. __________________________________________________
Evaluation
Was your experiment fair, or were there some things you could not keep the same?
[ observing, considering, evaluating ]
8Da2 Sorting kingdoms
1 Draw a table like the one below.
2 Look at the exhibition of organisms.
3 Write the name of each animal or plant in your table and decide which groups it is in. Use the diagram above to help you. For example, an ant is an animal, an arthropod and an insect.
4 Write down the reason why you have put it in the smallest of these groups. For example, an ant is an insect because it has six jointed legs.
[ observing, knowledge ]
8Da3 Classifying plants
Planning
1 Using books, CD-ROMs and the internet, make a list of plants that live in and around a freshwater pond.
2 List features that the plants have that could be used to put them into groups (e.g. type of root).
3 Decide how many groups you will have, and list the features of each. Then put the plants from your list above into the groups.
4 Complete a table like this for each group.
5 Why do you think plants in the same group share the same features?
6 a List any plants that were difficult to put into groups.
b Next to each, explain why it was difficult.
Optional extra
7 Now try to use your system to group plants that were not on your original list.
a Are there any plants that are very difficult to group?
b How could you change your system of classification to allow you to group these plants more easily?
[ planning, observing, considering, evaluating ]
8Da4 Animal acrostic
1 Fill in the answers to the questions on the grid. All the answers are animal groups.
a
b
c
d
e
f
g
h
i
j
k
a A crab is one of these.
b An invertebrate with a fleshy pad for movement.
c It has a backbone and moist skin.
d A vertebrate with feathers.
e It has wet scales, fins and gills.
f It has 6 jointed legs.
g A starfish is one of these.
h You are one of these!
i Any invertebrate with jointed legs.
j It has a backbone and dry scales.
k A spider is one of these.
2 Fill in the empty boxes to form a word in the shaded boxes.
3 Write a clue for this word.
__________________________________________________________________________
[ knowledge, literacy ]
8Da5 What's the plant?
1 Look carefully at these pictures. Write the words conifer, fern, flowering plant or moss underneath the correct picture.
a_________________
b_________________
c_________________
d_______________ _______________
e_________________
f_________________
g_________________
h_______________ _______________
2 Using the clues below, fill in the answers on this crossword.
1
2
3
4
5
6
7
8
Across
3 A fir tree is in this plant group.
5 Things made by some plants which are often brightly coloured.
7 Seeds and spores are used for this.
8 Conifers have needle-shaped ones.
Down
1 Group of small plants that make spores.
2 Ferns reproduce using these.
4 Contains seeds from a flowering plant.
6 Contains seeds from a conifer.
[ literacy, knowledge ]
8Da6 Grouping plants
1 Using the words in the box, fill in the correct word in each of the blank spaces.
cones conifers ferns flowering plants fruits mosses photosynthesis respiration spores water
a _____________________ and _____________________
both use seeds for reproduction.
_____________________ and _____________________
both use _____________________ for reproduction.
b _____________________ contain seeds in flowering plants.
c _____________________ contain seeds in conifers.
d _____________________ have no xylem vessels.
e Xylem vessels carry _____________________ around the plant.
f Plants make their own food using a process called _____________________ .
g The life process that plants use to release energy from food is called
_____________________ .
2 Find out the name of one plant in each group. Write the name of the plant and the group that it is in.
Name of plant
Plant group that it belongs to
[ literacy, knowledge, research ]
8Da7 Identification key
Here are some drawings of simple organisms that are found living in water.
Each one is a unicellular organism. This means that it is made up of just one cell.
In order to see them you would have to use a microscope.
Look carefully at the labelled features of these organisms. Using these features design a statement key to classify them.
Your key should allow someone else to find the names of the organisms if they were just given the labelled drawings to look at.
[ knowledge ]
8Db1 Tack population 1
You are going to estimate how many steel tacks are buried in a tray of sand.
- Tray of sand
- Tacks
- Magnet
- Small quadrat
1 Place the quadrat in the tray of sand. You are placing it randomly, so try not to look exactly where you are placing it.
2 Hold your magnet above the quadrat and see how many tacks are in the sand within the quadrat. Record the number in the results table.
3 Repeat steps 1 and 2 four more times. Remember to place the quadrat randomly each time.
Quadrat number
Number of tacks
Calculate the mean (average) number of tacks per quadrat. (Hint: Add up all five numbers and divide the total by 5.)
Mean number of tacks per quadrat = _________________________________________________
How much area did your quadrat cover? (Hint: Multiply the lengths of the two sides of your quadrat.)
Answer ____________________ cm2
What was the total area of the tray of sand?
How many quadrats would fit into the tray? (Hint: Divide your answer for the area of the tray of sand by your answer for the area of the quadrat.)
Answer ____________________
To work out the population of tacks in the sand multiply your answer for the mean number of tacks per quadrat by your answer for the number of quadrats that would fit into the tray.
Find and count all the tacks that were hidden in the tray.
Number of tacks in the tray = ____________________
Was your estimate near to the actual number of tacks in the tray?
Suggest how you could get a better estimate of the actual number of tacks in the tray.
8Db2 Tack population 2
2 Hold your magnet above the quadrat and see how many tacks are in the sand within the quadrat. Record the number in a results table.
3 Repeat steps 1 and 2 some more times. Decide how many times you will repeat steps 1 and 2. Remember to place the quadrat randomly each time.
1 Write down why you chose to repeat steps 1 and 2 the number of times you did.
2 Make a table to record your results
3 Calculate the mean (average) number of tacks per quadrat.
4 How much area did your quadrat cover?
5 What was the total area of the tray of sand?
6 How many quadrats would fit into the tray?
7 Calculate the total population of tacks in the tray. (Hint: Multiply the mean number of tacks per quadrat by the number of quadrats that would fit in the tray.)
8 Find and count all the tacks that were hidden in the tray.
9 Was your estimate near to the actual number of tacks in the tray? If not, try to explain why and how you could get a better estimate.
8Db3 Ecological terms
1 Look at the list of words that are often used when studying habitats. Match each word with its meaning by colouring them in the same colour.
community
A person who studies habitats.
ecologist
The place where an organism lives.
environment
The number of organisms of one species living in a habitat.
habitat
How much water vapour there is in the air.
humidity
All the different organisms living in the same place.
light intensity
A sampling square used to estimate plant populations.
microhabitat
The surroundings of an organism.
population
How bright the light is.
quadrat
Small area in a habitat where organisms live.
2 There are 150 lions living on the grasslands in one part of Africa. They feed on large animals such as gazelles, zebras and wildebeest and these feed on the leaves of acacia trees and grasses.
a What is the population of lions? ___________________________________________
b What is the community on the grasslands? ___________________________________
_____________________________________________________________________
c What is the habitat of the lions? ____________________________________________
[ knowledge, considering ]
8Db4 Quadrat studies
If you wanted to find out how much grass was growing on a field, it would be impossible to count the plants because there would be too many. Instead you can estimate the area of the field covered by the grass.
To do this, you would use a grid. This is a quadrat that is divided into 100 small squares. You count the number of small squares that the grass fills. For partly filled squares you ignore those that are less than half filled, but count those that are more than half filled.
If 20 squares out of 100 are filled the percentage cover is 20%.
1 Look at the grid above. The shaded areas represent patches of grass. Work out the percentage cover of grass in this grid.
2 If you were using this technique to estimate the grass cover in a large field, what would you have to do to improve the accuracy of your estimate?
Some students studied two grassy areas. One area was frequently walked over and used as a playing field. The other was rarely walked over.
The students estimated the number of five different plants growing in the two areas using a quadrat to see if they were affected by being walked on. The results are shown in the table below.
Plant
Number in rarely walked on area
Number in frequently walked on area
A
25
10
B
195
160
C
100
D
20
75
E
40
3 a Draw a bar chart to show these results. A bar chart has been started here to show you how to do this. You will need to use a key to show the differences between the bars.
b Which plant is most affected by being walked over?
c Which plant is least affected by being walked over?
d How is plant A affected by being walked over?
e How is plant D affected by being walked over?
[ knowledge, presenting ]
8Db5 Plants and light
Owen did an experiment to investigate the distribution of two different plants around a tree. He wanted to find out if they were affected by the amount of light.
He sampled the two plants along a transect running from the base of the tree in the shade out into the field where it was much brighter.
Owen positioned his quadrat directly under the tree and counted the number of both plants in it. He also measured the amount of light using a light sensor, placed at the centre of the quadrat.
He repeated his measurements every two metres and recorded his results in a table.
Here are his results.
Distance from tree (m)
Amount of light (units)
Number of plant A
Number of plant B
0
30
15
300
500
650
760
850
9
1 a Draw a line graph to show the number of each plant against the amount of light. Plot both sets of data on the same axes.
b Draw a curve of best fit through each set of data.
2 a What conclusion(s) can you make for plant A?
b What conclusion(s) can you make for plant B?
3 a Were there any results that didn't fit the pattern? If so, explain which ones they were.
b What should Owen do to improve the reliability of his results, so that he can make a firm conclusion?
4 Based on these results, what other environmental factor(s) might Owen decide to measure in order to explain the distribution of the two types of plant?
[ observing, presenting ]
8Dc1 Some common invertebrates
8Dc2 Invertebrate homes
What sort of places are woodlice most likely to be found in?
1 a In what sort of places are you likely to find the most woodlice?
b Why do you think this?
1 Choose two different areas to look for woodlice in. You might choose two different piles of leaves, one dry and one wet. You could take some leaves from the top of a pile and others from the bottom, or you might measure out two squares on different types of ground. Your teacher may give you some other suggestions.
2 If you are using leaves, you should collect the same volume of leaves from each place and count the woodlice in each. If you are looking for woodlice on the ground you should make sure that the two squares are the same size.
3 Record your results carefully.
4 Wash your hands when you have finished.
2 Which two areas did you choose?
3 What were the differences between the two areas?
4 Make a neat table of your results.
5 How did you make sure this test was fair?
6 Draw a bar chart of your results.
7 Using your results, say what sort of conditions woodlice like to live in.
8 Do your results agree with your prediction?
9 Why do you think woodlice like to live in the conditions you have identified?
10 What improvements could you make to this experiment?
8Dc3 Comparing environmental factors
You are going to find out if there is a relationship (link) between the amount of light and the temperature in two habitats and then see if these environmental factors affect the types of organisms that live there.
Do you think there will be a link between the amount of light and temperature? If so, what do you think the link will be?
Why do you think this?
- Field guides - Temperature sensor or thermometer
- Datalogger - Light sensor or light meter
- Camera
1 The two habitats I will investigate are:
Habitat 1 _________________________ Habitat 2 _________________________
2 Take or find pictures of the habitats, or make drawings of them.
3 Use sensors and dataloggers to measure and record the temperature and light intensity in the two habitats. You may need to take more than one reading and work out a mean (average).
4 Use keys and field guides to identify the organisms living in the two habitats.
5 Take or find pictures of the main organisms living in each habitat.
Fill in the table below to show the measurements you made.
Environmental factor
Habitat 1
Habitat 2
temperature
Fill in the table below listing the organisms you found.
Is there a link between the amount of light and temperature? If so, try to explain why. Did your findings support your prediction?
Are the two communities different? If so, try to explain why.
Present your work as a wall display.
[ observing, presenting, considering ]
8Dc4 A well adapted creature
Here is a list of conditions in an imaginary habitat:
- cold, wet and windy weather
- ground water is frozen
- steep rocky ground
- small animals live in dark caves
- tall trees with smooth bark grow in the mountains.
They have berries on their highest branches.
Design an imaginary creature that is adapted to survive in this habitat. Make a large drawing and label all its important features.
You will need to think about:
- what it eats and how it gets water
- how it moves around
- how it is protected from the weather.
8Dc5 Shellfish decisions
Freshwater shrimps are scavengers that feed on dead plant and animal materials. They live at the bottom of streams, rivers and reservoirs and walk along the bottom using their legs. They can swim using their legs and tail.
An experiment was set up to try and find out what type of surface freshwater shrimps prefer to live on. The diagram below shows the apparatus that was used.
Twenty shrimps were placed in the centre of the tray. The apparatus was left for one hour, and then the number of shrimps that had settled on each surface was counted.
The results are shown in the table.
Surface
Number of shrimps
sand
mud
14
pebbles
smooth stone
1 This is a picture of a fresh water shrimp.
a Look at its features and decide which animal group you think it belongs to.
b Explain why you have put it into this group.
2 Draw a bar chart to show the results of the experiment.
3 Which surface did the shrimps seem to prefer?
4 Suggest some reasons why you think the shrimps prefer this surface.
5 Suggest two things that would have to be kept the same in all parts of the tray to make sure that it was a fair test.
6 What could be done to improve the accuracy of the results?
[ knowledge, presenting, considering, evaluating ]
8Dc6 Survival adaptations
The table below gives the names and adaptations of some organisms.
Complete the table, giving a reason for each adaptation. (Hint: You may need to find out where some of the organisms live.)
In the last row fill in the information for another organism of your choice.
Organism
Adaptation
Reason
Earthworm
1 Soft slimy skin
2 Bristles
3 Moves away from light
Limpet
1 Sucker at bottom
2 Hard shell
Water milfoil
(a pond weed)
1 Long floppy stem
2 Leaves only present near surface of water
3 Flowers formed above the surface of the pond
Rabbit
1 Large ears
2 Powerful hind legs
8Dd1 Plant populations
You are going to try to work out an estimate of the population of a certain plant on a lawn.
Which plant will you investigate? ____________________________________________________
- Quadrat
You are going to take samples using a quadrat.
1 Take your quadrat and throw it about 3 metres in front of you. You are throwing it randomly, so try not to look exactly where you are throwing it. However, be careful that other people are not in the way.
2 Count the number of plants that you are investigating. Count all the plants that are inside the quadrat and any plant that is more than half-way into the quadrat. Write the number down in the results table on the next page.
3 Repeat steps 1 and 2 nine more times.
4 Now measure the total area of the lawn. Measure its length and width in metres and multiply the two numbers together.
Answer ________________ m2.
Number of plants
What was the mean (average) number of plants per quadrat? (Hint: Add all ten numbers and divide the answer by 10.)
________________________________________________________________________________
How much area (in m2) did your quadrat cover? (Hint: To work it out, multiply the lengths of two sides of your quadrat.)
What was the total area of your lawn? Answer ___________________________ m2.
How many quadrats would fit on the lawn? (Hint: Divide your answer for the area of the lawn by your answer for the area of the quadrat.)
To work out the estimated population of the plants on the lawn, multiply your answer for the mean number of plants per quadrat by the number of quadrats that would fit on the lawn.
Answer ________________ plants.
[ observing, considering ]
8Dd2 Sampling a lawn
How do you use a quadrat to estimate populations?
- Worksheet 8Dd/3
- One small square of transparent plastic sheet (1 cm by 1 cm)
1 Read the information below before you start.
2 Hold the plastic square 30 cm above the lawn on Worksheet 8Dd/3. With your eyes shut, drop the square. The area where it lands is a sample. The plastic square is acting as a quadrat.
3 Count the number of each different type of plant inside the square. Any plant that is more than half-way into the square is counted; any plant that is less than half-way in is not counted. Write down the number of plants that you have counted. Take 10 samples.
1 Draw a table to show how many plants you counted in each quadrat. Write down the total number of plants that you counted.
2 Work out the mean (average) number of plants per quadrat.
3 Work out the area of your quadrat and the total area of the lawn. Then calculate how many quadrats would fit on the lawn.
4 Now you can work out an estimate for the total number of plants on the lawn.
average number of
plants per quadrat
×
number of quadrats
that fit on the lawn
=
total number of
plants on the lawn
5 Each cm of the lawn and each cm of the quadrat square represents 1 m in real life. What area would they be if they were life size?
6 Work out the total population in the lawn of:
a daisy plants
b dandelion plants.
Show all your sample measurements and all your working.
7 Which of the named plants in the lawn do you think is the most successful? Explain your reasoning.
8 What can you say about the distribution of daisy plants?
8Dd3 The lawn
8Dd4 A tropical environment
A tropical fish tank.
Many people keep tropical fish at home in a fish tank. The environmental conditions have to be carefully controlled in order to keep the fish alive.
1 Explain what each of the following pieces of equipment is needed for:
a thermostat ____________________________________________________________
b heater ________________________________________________________________
c air pump ______________________________________________________________
d water filter ____________________________________________________________
2 Suggest two reasons why it is important to have plants in the aquarium.
3 Imagine that you were setting up a tropical fish tank at home.
a What resources would you have to provide to keep your fish alive and healthy?
______________________________________________________________________
b List the names of five living organisms that you might put into your tank.
8Dd5 Looking at a lawn
You will need worksheet 8Dd/3 to answer these questions.
1 What is the total population of thistle plants in the lawn? ___________________________
2 a There are no plants growing under the oak tree. Why do you think this is?
b Plants have to get things, like light and water, when other plants also need them. What is this called? Circle the right answer.
reproduction competition community
hibernation cohabitation
3 a Where are the moss plants found? __________________________________________
b Why do you think they are found only here and not in the centre of the lawn
c Some plants are only found in certain areas of a habitat. What is this called? Circle the right answer.
nutrition migration circumnavigation
distribution dispersion
4 List all the organisms in the community of the lawn. ________________________________
5 There are two animals on the lawn. One eats the other.
a Which animal is the predator? _____________________________________________
b Which animal is the prey? ________________________________________________
6 Woodlice like damp, dark places with rotting wood or leaves to eat. Name one place where they might be found.
8Dd6 Human activities and organisms
Human activities can have a big effect on the environment. Unfortunately most of our activities are harmful and affect the distribution of organisms living in the environment.
Sarah wanted to investigate the effects of some human activities on the distribution of organisms in a river. Look at this drawing of the river that she investigated.
1 a How could Sarah find out which part of the river had the highest population of bacteria?
b Briefly explain how she could measure the amount of dissolved oxygen in the water at points A, B and C.
c At which of these points in the river would you expect Sarah to find the lowest concentration of dissolved oxygen in the water?
d Explain your answer.
2 Alongside part of the river is a farm. The farmer uses a lot of fertiliser on his crops. After heavy rain much of this gets washed off the fields and drains into the river. What effect will this have on the population of plants growing in the river?
3 a Which point in the river do you think would be the safest place to catch fish that were going to be eaten by humans?
b Explain your answer.
c At which point in the river do you think there would be the largest population of fish?
4 Estimating the size of animal populations, such as fish in a river or foxes in a wood, is much more difficult than estimating plant populations.
a Explain why this is.
b Find out the name of a sampling method that Sarah could use to estimate the population of fish in the different parts of the river.
[ knowledge, research ]
8De1 Chains, webs and pyramids
Here are three food chains:
A grass → rabbit → fox
B wheat → field mouse → fox
C wheat → field mouse → grass snake
1 Sketch a pyramid of numbers for food chain A.
2 Use all three food chains to draw a food web.
3 Name one producer in the food web. ____________________________________________
4 Name a primary consumer. ____________________________________________________
5 Name a secondary consumer. __________________________________________________
6 a If the field mice died, what would happen to the number of grass snakes?
b Why would this happen?
c If the field mice died, what might happen to the number of rabbits?
d Why might this happen?
8De2 Pyramids of numbers
1 Sketch a pyramid of numbers for each of the following food chains:
a grass → rabbit → fox
b oak tree → caterpillar → robin → owl
c lettuce → slug → thrush → cat → flea
Farmer Giles.
Farmer Green.
Farmer Giles reared chickens, which he then sold for humans to eat. He worked out that to feed 1 human he would have to produce 40 chickens. To feed the 40 chickens he had to grow 10 000 corn plants.
Farmer Green just grew corn. He sold his corn to be fed to humans. He worked out that he needed to grow 1000 corn plants to feed 1 human.
2 a Draw the food chain for Farmer Giles' farm.
b Draw a pyramid of numbers for this food chain.
3 a Draw the food chain for Farmer Green's farm.
4 a What happens to the number of organisms as you go up each pyramid?
b What happens to the size of the organisms as you go up each pyramid?
5 a How much more land than Farmer Green would Farmer Giles need to feed 1 human?
b Why is it more efficient to produce food for humans from plants than from animals?
8De3 Changing populations
1 Look at this graph. It has two vertical axes, one for the rabbits and one for the foxes. It shows how the populations of foxes and rabbits have changed in one area. Each population was measured at the middle of every year.
a Which animal is a predator?
b Which animal is preyed upon?
c How many rabbits were there in 1989?
d How many foxes were there in 1993?
e In which year were there the most foxes?
f Explain why the number of foxes fell between 1988 and 1990.
g During 1996 the rabbit population was almost totally wiped out. Give one possible reason for this.
h In 1997 there were no foxes. Give one reason for this.
2 A meadow is 400 m long and 200 m wide. 10 quadrat samples were taken at random around the field. The area of each quadrat was 0.25 m2. The total number of buttercup plants in all the quadrats added together was 5.
a What is a quadrat?
b Why were the samples taken 'at random'?
c What was the area of the meadow?
d What was the total area sampled?
e Estimate the number of buttercups per m2.
f Estimate the total population of buttercups in the field.
[ knowledge, numeracy ]
8De4 The human population
1 Use the data below to draw a graph showing how the world's human population has increased since 1500. Join the points together with a smooth curve. Leave space on the graph to continue it further (up to 2025 and 10 000 million people).
Year
Estimated world population (millions)
1500
400
1550
420
1600
480
1650
575
1700
640
1750
725
1800
925
1850
1200
1900
1950
2400
1975
4000
2000
6100
2 Most populations are kept in check by other factors (the human population is an exception). Name two factors that might keep a population of rabbits in check.
3 Why do you think that the human population has increased so much in the last 100 years.
4 Continue your graph to estimate the number of people in the year 2025.
5 How might the growth in human population be slowed down in the future?
6 In various places around the world, there are too many people and not enough food. How does this affect the population in these areas?
7 Wars often cause people to leave an area. This is called emigration. The same word is used for other animal populations. What might cause foxes to emigrate?
8 People arriving in a new area is called immigration. What effects might human immigration have on an area?
9 Why might foxes immigrate to a particular area?
10 Find out about the 'Black Death' and how it affected the population of Britain in the 14th century.
[ knowledge, research, considering ]
8De5 Pyramids of biomass
Each level on a pyramid of numbers is called a trophic level. Animals that are on the same level in two different pyramids of numbers are said to be at the same trophic level. Producers, for example, are always at Trophic level 1.
Pyramids of numbers do not take into account the size of the organisms. A better way of showing things is to use a pyramid of biomass. This shows the actual mass of material at each trophic level. A sample is taken and the masses of the different organisms are measured. This often involves drying the organisms in an oven to get rid of all the water. How wet or dry the weather is can affect how much water is found inside an organism. This would affect the biomass and might make the measurement inaccurate. So, the biomass is a measure of the dry mass of material at each trophic level.
A pyramid of numbers.
1 Explain why the pyramid of numbers above is not shaped like a pyramid.
2 What number tropic level are the ladybirds at?
3 Draw a food chain for this pyramid of numbers.
4 What do you think the word 'biomass' means?
5 Sketch a pyramid of biomass from the pyramid of numbers above. You do not need to add any figures, just draw the shape.
6 To work out a pyramid of biomass, the dry masses of the organisms are used. Why?
7 The biomass of an oak tree changes during the course of a year. Why is this?
8 Only about 10% of the chemical energy in an organism's food is used for growth. What happens to the rest?
9 The biomass at each trophic level gets smaller as you go up the pyramid. Why do you think this is? (Hint: Think about 'energy loss'.)
10 A difficult question! The diagram below shows a pyramid of biomass for a field. The units are g/m2. Describe what this pyramid tells you in as much detail as you can.
8D Summary Sheets
Ecological relationships
Habitats and environments
A habitat is the area where an organism lives. Non-living factors in a habitat are called physical environmental factors. Examples include how light it is and what the temperature is. These make up the surroundings, or environment, of an organism.
Small areas in a habitat are called microhabitats. For example, the fur on a fox is a microhabitat.
All the plants and animals that live in a habitat make up a community. Within a community, the total number of one species is called a population. There will be a population of foxes in a wood.
In order to survive in a habitat, organisms need various resources. An animal needs food, water, oxygen, shelter and it needs to find a mate to reproduce. Plants need light, water and carbon dioxide in order to make food. They also need mineral salts (nutrients), oxygen and space to grow.
Adaptations
In any habitat, the organisms living there must be adapted to survive the environmental conditions within that habitat. Members of the same community may have similar adaptations to cope with the problems of their habitat. For example, many small animals and plants which live in fast-flowing rivers are adapted to stop them being swept away. In ponds, free-swimming animals and floating plants can survive because there is no current to wash them away.
All the places in an environment where an organism is found is called its distribution. For example, in a pond habitat pond skaters are found on the surface of the water. They are adapted to living here because they have bristles on the ends of their legs, which prevent them from breaking the surface film of water. They feed on dead insects floating on the water.
Organisms that are better adapted to survive in an area will have a better chance of survival.
Classifying living organisms
Each different type of organism is called a species. There are so many species that we need to put them into groups. This is called classification. The largest groups are called kingdoms and the biggest of these are the plant kingdom and the animal kingdom. The Summary Sheets for Unit 7D Variation and classification show how animals are classified into groups.
The main difference between plants and animals is that plants can make their own food by photosynthesis.
There are four main plant groups.
Sampling methods
Ecologists are scientists who study habitats. They catch organisms using various sampling techniques, then use keys and field guides to identify them.
A pooter is used to collect small invertebrates.
A Tullgren funnel is used to collect invertebrates from leaf litter.
A pitfall trap traps small animals that crawl along the ground.
Tree beating is used to collect animals that live in trees or bushes.
Pond dipping is used to collect organisms from different parts of a pond.
A sweepnet is used to collect organisms from long grass.
Ecologists often need to know the size of a population. It would be impossible to count all the organisms in a habitat, so they take samples and then estimate the total number of organisms.
A quadrat is a sampling square used to estimate plant populations. The quadrat is placed randomly on the ground in different parts of the habitat and the number of plants inside it is counted each time.
The more samples that are taken, the more reliable an estimate will be.
Ecologists also measure the physical environmental factors, like how warm it is and how much oxygen is dissolved in pond water, using sensors and dataloggers. They then look to see if there are any links between the factors, such as, the warmer the water the lower the oxygen level is.
Feeding relationships
Food chains and food webs show the feeding relationships between different organisms in a habitat. (See Summary Sheets for Unit 7C Environment and feeding relationships).
The numbers of organisms at each level in a food chain can be shown as a pyramid of numbers. The size of the bars shows the number of organisms. Usually there are fewer organisms as you go along a food chain because energy is lost at each level, for example, for movement. Sometimes the pyramid has an unusual shape if the organisms are very different in size.
grass → caterpillar → robin → sparrowhawk
rose bush → aphids → ladybirds
Populations
The size of a population is affected by several factors.
- Animals compete with each other for resources such as food, water and shelter.
- Plants compete for light, water, nutrients (mineral salts) and space.
- If there are not enough resources the population will decrease.
- Disease can kill organisms.
- The populations of predators and prey are linked. When there are a lot of prey organisms, the number of predators increases because they have plenty of food.
This decreases the number of prey, which then leads to a decrease in the number of predators.
- Harsh weather conditions can reduce populations.
Living organisms depend on others for their survival. For example, plants depend on insects for pollination.
8D Target Sheet
Topic
Targets
Before the unit
I have learned this
I have revised this
8Da
Know the names of the five groups of vertebrates.
Know the main features of the main invertebrate groups.
Know about the four plant groups.
Know that plants are made of cells. Some of these cells carry out certain jobs like transporting water.
8Db
Know what physical environmental factors are.
Know some sampling methods.
Know how to estimate population sizes.
Know how people study habitats.
8Dc
Know about the equipment that is used for sampling.
Know how to use keys to identify organisms.
Know some adaptations of plants for obtaining nutrition.
Know about communities and microhabitats.
8Dd
Know about distribution.
Know that organisms compete.
Know how changes in populations occur.
Know what organisms need to survive.
8De
Know what a producer is.
Know the words to describe different animals in a food chain.
Know that food chains and webs show what eats what.
Know how to show the numbers of organisms in a food chain.
8D Word Sheets
8Da - In the environment/Animal groups/Plant groups
Word
Pronunciation
Meaning
adapted
When the features of an organism help it to survive in a habitat, it is adapted to that habitat.
amphibian
Vertebrate with moist skin, e.g. frog.
animal kingdom
The group of organisms that contains all vertebrates and invertebrates.
arthropod
arth-row-pod
Invertebrate that has jointed legs, e.g. fly, spider.
bird
Vertebrate with feathers, e.g. eagle.
classification
clas-if-ik-ay-shun
Sorting things into groups.
cone
Something used to carry the seeds of conifers.
conifer
Plant with needle-shaped leaves. Reproduces using seeds found in cones.
cuticle
Layer of cells on leaves that is waterproof.
echinoderm
ek-eye-no-derm
Invertebrate that has a body in five parts, e.g. starfish.
The conditions around an organism caused by physical environmental factors.
exoskeleton
ex-O-skel-e-ton
Thick outer covering found in arthropods.
fern
Plant that has many small waterproof leaves. Reproduces using spores.
fish
Vertebrate with wet scales, e.g. salmon.
flowering plant
Plant with large, flat leaves. Reproduces using seeds found in fruits. Fruits and seeds form inside flowers.
fruit
Something used to carry the seeds of flowering plants. Can be fleshy or dry.
The place an organism lives in, e.g. woodland.
invertebrate
in-vert-eb-rate
Animal without a backbone.
mammal
Vertebrate with hair and produces milk, e.g. human.
mollusc
Invertebrate that crawls on a fleshy pad, e.g. snail.
moss
Plant with many thin leaves but without roots and xylem. Reproduces using spores.
photosynthesis
foto-sinth-e-sis
Process that plants use to make their own food. It needs light to work. Carbon dioxide and water are the reactants. Food (a sugar called glucose) and oxygen are the products.
physical
The non-living conditions in the environment of an organism, e.g. temperature, light.
environmental factors
plant kingdom
Group of organisms that are able to produce their own food and have specialised cells.
reptile
Vertebrate with dry scales, e.g. snake.
root
Plant organ used to take water out of the soil.
seeds
Grow into new plants. Made by conifers and flowering plants.
spore
Very small part of a plant that can grow into a new plant. Made by mosses and ferns.
vertebrate
vert-eb-rate
Animal with a backbone.
xylem vessel
Transports water through a plant.
8Db - Detective work
com-mew-nit-ee
All the plants and animals that live in a habitat.
A person who studies the environment.
estimate
Provide a rough idea about the numbers of something or the size of something.
The amount of water vapour in the air.
pitfall trap
Sampling method used to collect small animals that live on the ground.
pond dipping
Sampling method used to collect organisms from ponds.
Total number of individuals of the same species in a habitat.
A square frame, thrown randomly on the ground, which is used to sample the plants in an area.
sample
A small part of something. If you sample something you take a small part of it. You use your results from the small part to suggest what the rest of it is like.
sweepnet
Sampling method used to collect small animals from long grass.
tree beating
Sampling method used to collect animals from trees and bushes.
Tullgren funnel
Sampling method used to collect small animals from samples of, for example, leaves.
uneven distribution
When a plant or animal is not found all over a habitat, only in certain places where the habitat is suitable.
8Dc - Homing in
pooter
A small container connected to two tubes. Used to catch tiny animals.
8Dd - Populations
adaptation
add-app-tay-shun
The features of an organism that allow it to live in its environment.
compete
All organisms need some of the same things and so each organism has to try to get these things before another organism does. For example, plants compete with one another for light.
competition
comp-pet-tish-un
Organisms compete with each other for food, light and space in a habitat.
distribution
diss-trib-you-shun
The places where an organism can be found in a habitat.
predator
An animal that catches and eats other animals.
prey
pray
An animal that is caught and eaten by another animal.
8De - Webs/Living pyramids
chemical energy
The kind of energy stored in chemicals. Food, fuels and electrical cells all contain chemical energy.
consumer
An organism that has to eat other organisms to stay alive. Animals are consumers.
food web
Many food chains linked together.
primary consumer
The first animal in a food chain.
producer
An organism that is able to make its own food.
pyramid of numbers
Way of showing the numbers of different organisms in a food chain.
secondary consumer
The second animal in a food chain.
tertiary consumer
tersh-ary
The third animal in a food chain.
top predator
The last animal in a food chain.