Download 5B Life Cycles

5B LIFE CYCLES : KEY WORDS
AND
PHRASES
 words and phrases associated with life processes e.g. reproduction, life cycle
 names for parts of a flower e.g. stamen, style, stigma, sepal, petal, ovary, pollen
 names for processes related to life cycles and associated verbs
e.g. reproduction/reproduce, germination/germinate, pollination/pollinate,
fertilisation/fertilise, dispersal/disperse
 descriptions and explanations using a sequence of ideas.
adaptation
animal
anther
bacteria
camouflage
carpels
colonise
competition
control
cotyledons
decay
dispersal
distribution
ecosystem
fertilisation
filament
food chain
germination
growth
habitat
life cycle
microorganisms
micropyle
nectar
nutrients
organism
ovary
petals
plant
plumule
pollination
populations
predator
prey
radicle
root
seeds
sepals
shelter
shoot
species
stamens
stem
stigma
style
succulents
wind dispersal
woody stems
xylem
5B LIFE CYCLES : KEY KNOWLEDGE
Seeds need light, water and space (to get air and sunshine) in order to grow after they have
germinated.
Plants grow from seeds that are in the soil even though we cannot see them.
Some plants grow from pieces of root or underground stem left in the soil when it is dug.
Plants need light to produce food for growth.
Green leaves are essential for the plant to carry out this process.
Some plants e.g. radish, potato, carrot, have an underground food store called a tuber.
New plants can grow from the tuber (as well as from seeds also produced by these plants).
Plants take up water from the soil through their roots. It is transported through the stem
to other parts of the plant
The water is given off from the leaves as water vapour. This water normally goes out into
the atmosphere but will condense inside a closed polythene bag covering the leaves.
Some plants take up and give off more water than others.
A control is used in an experiment to compare experimental data with 'normal' conditions.
Some plants, e.g. cacti and succulents are especially adapted to living in dry conditions.
Plants take up water from the soil through their roots and pass it up the stem in xylem
vessels.
They can also take up substances dissolved in water e.g. ink, but not insoluble substances, e.g.
chalk.
Nutrients dissolved in water can make plants grow and flower more vigorously. These may be
naturally present or can be added in solution e.g. Baby Bio.
Life processes including growth, nutrition and reproduction are common to plants
Most flowers have: sepals, petals, stamens (anthers and filaments) and carpels (stigma, style
and ovary). Flowers of the same species have common characteristics i.e. the same number,
shape and arrangement of sepals, petals, stamens and carpels. In flowers of different
species the size, shape and arrangement of these is different.
Seeds need space to grow away from the parent plant. They may be eaten by birds e.g.
blackberries;
 flung away as pods dry, e.g. gorse;
 blown away by the wind e.g. dandelion;
 stuck to animal coats, e.g. burdock;
 buried by animals, e.g. hazelnuts
Insects visit flowers in search of nectar. As they reach deep into the flowers, pollen from
the stamens is brushed off onto their bodies.
The insect moves on to other flowers carrying the pollen to the stigma where the male
gamete travels down the pollen tube to the ovary and fertilizes the seeds. Most plants
cannot pollinate their own flowers (usually stamens ripen before the seeds are ready to be
fertilized). Cross pollination results in strong new plants. When the petals fall, the seeds
ripen, they are dispersed from the plants and grow into new plants
Trees have flowers and seeds. Seeds can grow into trees. Some trees have two kinds of
flower. These can be on the same tree or on different trees of the same kind. Catkin
flowers have lots of pollen as they depend on the wind to blow it on to the stigma of flowers
on another tree.
Grasses are also wind pollinated.
Seeds cannot grow (germinate) without water.
A bean seed has:
- a small hole, the micropyle, which allows water to enter the seed and soften it;
- an outer covering, the testa, which protects the seed;
- two halves, the cotyledons, which are the food store for the growing plant;
- the radicle and plumule, which become the root and shoot of the growing plant.
As the plant grows, the food store is used up and the bean shrivels.
A number of different species live together in a pond, an ecosystem.
They are specially adapted for life (or a stage of their life cycle) in water.
All animals need oxygen. This may be obtained from the air or from dissolved oxygen in the
water.
Different species are found in different areas of the pond, or at different levels.
Life processes including movement, growth, nutrition and reproduction are common to animals.
Several species of animals live in one habitat.
Animals living in a habitat, i.e. under stones or logs, are especially adapted to it.
Animals live in a habitat because the conditions there suit them, e.g. temperature, moisture,
light and shelter.
If animals are moved a short distance from their habitat, many will return.
Life processes, including movement, growth, nutrition and reproduction are common to
animals.
5B LIFE CYCLES : THINKING SKILLS
Information-processing skills
These enable children to locate and collect relevant information, to sort, classify, sequence,
compare and contrast, and to analyse relationships.
5B LIFE CYCLES : ICT
IDEAS
Unit 5B Life Cycles
1. Pupils could use CD-ROMs to view newly born animals and gather information about
gestation periods.
2. Use a computerised microscope to observe stamen with pollen and pollen grains from a
number of sources – (class activity).
3. Connecting an Intel microscope to a computer and data projector would allow the
whole class to make close observations of flower structures. It is also possible to scan
leaves and flowers for the children to look at. Children could produce a display of a
life cycle using a word processor, some children might simply order pictures, most
children could add labels and some could make comparisons between different life
cycles.
Web Sites:
www.endangeredearth.com/
www.panda.org/
www.panda.org/kids/
5B LIFE CYCLES : TESTABLE QUESTIONS
5B Unit Life Cycles
1. How is seed germination affected by size/ soaking/ light/ temperature/ motion?
2. What are the possible factors which affect the rate at which frogspawn develops in
the classroom compared to the pond?
3. What do seeds require in order to germinate?
4. How will pollution effect plant growth/seed germination?
5B LIFE CYCLES : BIG
IDEA
All living things will die; and if the species is to continue, and is to have any future, then it
needs to reproduce. Reproduction produces new offspring of their kind - plant or animal. As
the old die off, the young take their place. A species that is good at reproduction will
survive.
Green plants reproduce by flowering. The flowers contain the
cells that will combine to produce the seeds and then the new
plant. Ideally, cells from two different plants will combine;
but if all else fails, a plant can fertilise itself to produce
seeds.
The flower produces female egg cells in its ovary. The ovary
has a sticky stigma on a long style to catch the male pollen
cells. The pollen cells are produced in the stamens. These
tiny specks are carried to the stigma of another plant by the
wind, or on an insect. The insect gets sticky, sugary nectar
from one plant and gives it to another plant - like a postal
service.
When the egg cell is fertilised, it develops into a seed. The ovary may develop too, into a
fruit. Because now the challenge is to move the seed - away from its parent plant to
somewhere where it will grow. The wind may blow it, or water may carry it; it may stick to a
passing animal, or be swallowed by one, only to emerge in the animal's droppings and grow.
The new plant will flower in turn.
This is all a risky business - and so lots of pollen and seeds are produced to help ensure that
new plants will grow. The whole process - from flower to flower - is called the flower's life
cycle.
5B LIFE CYCLES : ASSESSMENT GRID
5B
Life Cycles
Date
Level 3
1. name the parts of a flower and sort a series of pictures to demonstrate the life
cycle of a plant or human;
Level 4
2. name the male and female parts of a flowering plant;
3. explain the phrase 'optimum growing conditions';
4. describe two methods of pollination and two methods of dispersal;
Level 5
1. explain the need for seed dispersal in terms of competition and nutrition;
Sc1
Investigating the effects of pollution on plant growth
Planning Pupils can:
Level 3
Level 4
Level 5
make a supported
prediction, e.g. 'I think
that the seeds growing in
salt water will germinate
because plants grow near
to the sea';
plan a fair test in which
they vary only one thing,
e.g. amount of
fertiliser/pollutant, type
of seed;
plan the investigation
giving a scientific
explanation, e.g. 'I am
going to change the
amount of fertiliser given
to each dish of seeds
because I think that if I
give some too much it will
have no further effect on
seed germination';
Obtaining and Presenting
Pupils can:
measure carefully
quantities of water
and/or fertiliser,
pollutant;
Considering and
Evaluating Pupils can:
identify a simple pattern,
e.g. 'all the seeds grown in
the warmth germinated'.
make a series of
observations of the
germination of their
seeds;
link their conclusions to
the plants' need for
water and warmth in
order to germinate.
make a series of
observations and use
averages of the
measurements as
necessary when
encountering odd results;
calculate the rate of
germination in terms of
percentages of the seed
samples, or plot a growth
curve on a graph, length
against time.
5B LIFE CYCLES : DISPLAY
Seeds
Collections:
Seeds and seed cases; fruits: familiar ones and more exotic, e.g. kiwi fruit star fruit,
watermelon, etc. - and tomato, marrow, fruit sliced in different ways to expose the seeds;
seed cases from flowers e.g. poppy heads, love-in-the-mist honesty (display these with a
sample of the seeds); tiny seeds sprinkled onto adhesive tape to aid observation and handling;
seed pods - peas and runner beans; conkers and their prickly seed cases along with sweet
chestnuts, hazel nuts, beech nuts, coconut etc dried grasses, ears of wheat or barley; from
the kitchen: dried beans, rice, nuts and seeds used for flavouring, e.g. fennel cardamom,
caraway etc.; advertising posters or free samples from seed merchants ; packs of seeds.
Display:
Slice open unusual or colourful fruits—observe using hand lenses and draw or paint
Make a scarecrow to scare away the birds from seeds you may have planted outside. Make
miniature scarecrows and stick them into flowerpots filled with soil.
Observational drawings or paintings of seed heads, grasses, dandelions, etc. (White crayon on
black, or white wax with a dark wash is particularly effective.)
Make a seed picture frame. Arrange seeds in a pattern against a frame on card and attach
using good quality glue. When dry, apply a coat of paint which has PVA glue mixed with it.
Use it to display artwork or photographs.
Design a seed packet, or container, perhaps for sale at a summer fair.
5B LIFE CYCLES : EQUIPMENT
5B
collection of pictures of plants with fruit e.g. apple trees, vines, dandelions, beans,
horse chestnut, tomatoes
hand lenses/microscopes
examples of flowers e.g. mallow, buttercup and pictures of flowers
collection of fruits and seeds including those dispersed by different mechanisms
pictures illustrating the plants from which seeds come
rapidly germinating seeds e.g. radish, spring onion
thermometers
containers in which to germinate seeds
soils etc in which to germinate seeds
secondary sources e.g. video, CD-Rom, reference books showing newly born animals and
giving information about gestation periods
5B LIFE CYCLES: PROGRESSION
OF IDEAS
Plants
The life cycle ensures that new plants are produced.
Plants only produce flowers at certain times of the year.
Flowers are part of the plants reproductive system.
Flowering plants have different parts that have to be combined to produce seeds. In
order for this combination to occur pollen has to be transferred from the anther of one
flower to the stigma of another. This is called pollination.
Pollination can take place in different ways but the two most common methods are by
insects or the wind.
If pollination is successful a seed will develop
Seeds need to be carried away from the parent plant so that the new plants can survive
and grow healthily.
Seed dispersal is the process by which seeds are carried away from the parent plant.
Seed dispersal is carried out in a variety of ways by different plants.
All plants of the same species use the same method of seed dispersal.
When a seed starts to grow into a plant it is said to have germinated.
Water and warmth are required for germination to occur.
Humans
Humans are alive.
Humans move.
Humans grow.
Humans feed.
Adults have babies.
Babies grow into children and then into adults.
Humans are animals and have processes in common with all other animals’ e.g. they
move, feed, grow and reproduce.
Humans change gradually as they grow older.
Humans start their life as babies and change into children, as they grow their bodies
change.
Children grow into adolescents because changes occur in their bodies.
Adolescents grow into adults because more changes occur in their bodies.
Humans need food for energy.
Humans need food for growth.
5B LIFE CYCLES : PROGRESSION
RELATED TO
SCIENCE ENQUIRY
Variation and Classification
Context
Recognise similarities and differences between themselves and others.
Learn to group living things using observable similarities and differences.
To use observable features to group locally found living things and to use a key for
that purpose of identification.
Using characteristic features devise a simple key to help identify animals and plants
belonging to a common group
Concepts
There is a wide variety of living things and these can be grouped by observable
characteristics.
Living things reproduce and some characteristics are inherited from one generation to
the next.
Inherited characteristics help living organisms to survive by helping them adapt to the
environment in which they live.
Vocabulary and S.I. Units
KS1
Animal, autumn, backbone, bird, coat, conditions, egg, environment, fish, flower, insect, leaf,
limbs,
mammal, offspring, petal, plant, reproduce, root, seeds, skin, spring, stem, summer, tree,
S.I. Units: Length - metre (m), Mass - kilogram (Kg)
KS2
Amphibian, carnivore, chromosomes, classification, cycle, extinct, fish, genes, group, inherit
invertebrate, key, kingdom, reptile, variety, vertebrate, zone
S.I. Units: Length - metre (m), Mass - kilogram (kg)
Variation and Classification
K
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Q
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Level 1
2
3
4
5
6
Know some obvious
physical differences
between common
animals/plants around
them. Be aware there is a
variety of living things
and they are different in
appearance and able to
describe differences
between common animals
e.g. cats/ dogs.
Know they can group
animals/plants by simple
observable features like
number of legs or skin or
shape of leaf. Able to
group animals into large
common families like dogs
showing a notion of share
common characteristics
e.g. recognise a small and
large dog are both dogs.
Recognise the obvious
features that make an
organism best suited to is
environment such as birds
having wings for flying
but these are different
in animals from different
groups and although
similar they are different
within a group e.g. insect
wings from bird wings or
leaf shape.
Know animals can be
grouped by shared
observable
characteristics such as
skin, number of legs,
wings etc., so they
classify simple animals
into groups like insects,
mammals etc. Be able to
use a simple key to group
organisms into simple
groups
Use scientific ideas to
describe when animals or
plants reproduce
observable inherited
characteristics are
passed between parent
and offspring during
reproduction. Know that
organisms are classified
according to shared
features and devise a
simple key.
Describe simple
differences between two
common animals or plants
like dog, cat and
themselves or a pine tree,
oak tree; or a tulip and a
daffodil. Describe
observed physical
differences by talking or
record by pictures
/simple charts the
differences.
In observations describe
key factors to sort
animals and plants into
groups. Make comparisons
of different common
characteristics like
shape, size of leaf.
Compare length/shape
using non- standard
measurement and record
results in a prepared
chart. In a description o
shape comment on the
tree shape and where
found
Responding to questions
they suggest factors like
light or soil type to vary
in an investigation on
plants and their
differences. Simple
predictions such as a
plant with broad leaves
needs more light than a
small leaf plant. Make
simple measurements of
length, width and shape
of leaf, enter them in
tables and write about
the environment the
plants grow best in.
Explain the changes,
differences they see and
the simple patterns in
the results.
Investigate a local
environment using simple
IT such as sensors for
temperature and light and
record in simple spread
sheets. Use a simple key
to identify/ group
organisms found in that
environment and link them
with conditions in the
place they were found.
Make simple predictions
about what will hap- pen
if conditions change
Record in tables and
interpret patterns to
draw a simple causal link
between habitat and
organism.
Identify key differences
between organisms in an
environment and classify
them using a key. Predict
using science knowledge
what variation to expect
in two different
environments such as a
pond and a wooded zone,
give a reason for the
variation they expect.
Measure, record simple
repeat differences in
conditions. Draw simple
charts or maps to show
location, density of
organisms. Using the
evidence explain with
science ideas the
Know that some
differences are inherited
by information stored on
cellular components called
chromosomes. An
offspring inherits two
components of inherited
characteristics on genes
one from the male and
one front the female.
Know a species is an
organism with genetically
inherited characteristics.
Identify key factors
affecting the inheritance
of a characteristic like
hair colour or tongue
rolling. Using IT
spreadsheets and science
ideas make predictions
about the offspring. Look
for relationships in the
data such as eye colour
with hair colour. Use the
evidence and related
scientific ideas to justify
the conclusion they have
formed to make
predictions about
offspring.
5B LIFE CYCLES : BACKGROUND SCIENCE
A living thing is characterized by the fact that it has the potential for movement,
respiration, sensitivity to stimuli, growth, reproduction, excretion and feeding.
Young
children tend to over-emphasize movement as the sole characteristic of a living organism. A
living thing has the ability to carry out all or most of these processes at some stage during
its life cycle. For example, a dried pea has no obvious signs of being alive, but if it is put in
water and then planted it may quickly demonstrate that it is living. As a dried pea it was
'ticking over' (respiring very slowly) until conditions were suitable for growth to take place.
As a plant, the pea demonstrates its ability to carry out all the processes of living things. It
is the combination of all these processes that enables us to identify something as living. All
living things are made up of discrete microscopic units called cells.
These contain the
information needed to carry out the vast number of chemical reactions that allow the living
thing to remain alive.
Effects of the environment
Shape, colour, size, and behaviour are some of the characteristics that may be changed as
the result of environmental factors. In some cases the effect is only slight, but in others it
can be quite dramatic. For example, hydrangea plants generally have pink, white or blue
flowers. However, the blue flowers occur only when the plant is growing in an acid soil; in
other soils the flowers are either pink or white. The effects of environmental influences on
organisms are generally identified by an examination of physical features. However, the
consequence of such influences on characteristics such as behaviour and intelligence in
humans is by no means clear and the evidence is far from conclusive.
Effects of heredity
Offspring inherit characteristics from their parents. For sexual reproduction to occur a
male and a female parent are needed. The offspring show some of the characteristics of
each parent and so cannot be exactly like either of them. In addition, the way in which the
various characteristics come together during reproduction involves a high degree of chance.
Thus each individual offspring will have the characteristics of their parents combined in
different ways, so they will also vary from each other. In some organisms reproduction can
also take place asexually. In this process one individual produces an offspring by dividing in
two or producing another structure which eventually becomes independent.
Plants are
produced asexually when a gardener takes cuttings.
Offspring resulting from asexual
reproduction are almost exactly like their parents. Similarities are retained but there is
little or no opportunity for any variation. Thus variation within a species occurs as a result
of sexual reproduction.
Sudden changes in characteristics
From time to time offspring will be produced with a characteristic that is very distinct and
unexpected.
These sudden changes, called mutations, occur with varying frequency in
different species and are the result of changes that have taken place during the formation
of the male sex cells (sperm or pollen) and/or the female sex cells (egg or ovum). When the
egg and sperm come together at fertilization these new characteristics become part of the
offspring. Often these changes are lethal so the offspring do not live, but occasionally the
mutation results in a characteristic that is of benefit to the individual. The peppered moth
used to be white, but in the nineteenth century a black form appeared which was better able
to survive on tree-trunks blackened by smoke in Britain's cities.
Plants
The life cycle of a flowering plant
Many of the plants which add colour to our gardens each year, such as antirrhinums, asters,
lobelias and so on, are referred to as annuals because they complete their life cycle in one
growing season. Other plants such as Canterbury bells are biennials: that is, they take two
years to complete a life cycle, from seed to producing seeds. Perennials are those plants such
as roses which flower each year, the same plant surviving from one season to another.
Plant reproduction
Plants can reproduce both sexually and asexually. In sexual reproduction, a male and a female
part from either the same or different plants come together. Pollen is usually then
transferred from the stamens, considered to be the 'male' part of the flower, to the stigma,
considered to be the 'female' part of the flower, and this results in fertilization of the
plant's seeds.
It is possible for parts of a plant other than seeds to grow; for example a potato tuber, a
willow twig or a carrot top. In these cases reproduction is asexual (vegetative), as it does
not involve the male and female part of the plant.