School Science Lessons
Biology experiments
Updated: 2008-12-21
Please send comments to: J.Elfick@uq.edu.au
9.1.1
Bird study
See diagram 9.1 | See
diagram 9.1.1 | See diagram
9.1.2 | See diagram 9.1.3
9.1 Study beak types and observe the feeding behaviour of birds with
a
particular type of beak. Investigate different beak uses.
9.2 Study feet types and observe the behaviour of birds with
particular
feet type, e.g. wading, walking, swimming, perching, hunting, and
carrying objects. Many birds use their feet in perching or grasping,
e.g. the woodpecker. Other birds use their feet primarily for walking,
e.g. quail. Water fowl have webbed feet for wading and swimming,
e.g. ducks, pelicans. Hunting birds have large talons, e.g. hawks, owls.
9.3 Make casts of foot imprints found in soft soil or mud. Use
cardboard, paper clips, plaster of Paris and a spoon. Form a cylinder
with cardboard and
a paper clip. Put the cylinder around a track. Pour a plaster of Paris
into the cylinder. When the plaster hardens, a raised or negative print
of the track forms. Use the negative print to make a positive print.
Organize casts into categories based upon use or function.
See 3.67:
Strength of plaster of Paris
9.4 Observe the activities of birds in nests but do disturb the
nesting
behaviour of the birds.
See diagram 9.1.4: Parrots
Observe nest building, bird habits and
the materials used. Abandoned nests reveal detail of construction and
small
organisms that live in the nesting materials. After hatching, observe
the feeding and care of young. Note how defence of its territory by a
bird is an important behaviour in limiting the bird population in a
given area. Note aggressive bird behaviour in nesting and feeding
areas. Be careful! Nesting birds may attack children.
9.5 Birds may be attracted by houses that will help their nest
building
behaviour.
See diagram 9.1.5: Bird houses
The internal size must be suitable for the nest of the bird.
The entry hole must be of appropriate size. Leave the interior
unpainted. Put the house where the bird will use it and at the proper
height above the ground. Small houses with tiny openings lure small
birds. For example, a house for wrens should be 10 cm by 10 cm by 12
cm,
with an opening hole 2.5 cm diameter. Some birds will nest in an open
structure, e.g. the robin. Some birds need a house that resembles a
tree trunk and has an opening 10 cm across, e.g. screech owls.
9.6 Make feeders to attract birds
Be
careful! Use safety
glasses and thick gloves when building these
feeders. Handle metal netting, wire and tin with care. Always cut away
from the body.
1. Mixed seeds and suet (sheep kidney
fat) attract many bird types at all seasons of the year. Bird
feeders attract not only birds but also small mammals, e.g. mice and
squirrels. Observe food preferences, times of
feeding activity, and other behaviours.
2. Make a cubical suet
cage from metal netting and nail it to a tree or post. When cutting the
metal netting,
leave wire lengths protruding to be bent over adjoining squares to hold
the sides together. Leave the front panel free at the top so that it
may be opened to replace the suet. Fasten the closed cage with wire
loops.
3. Make an open bird feeder from wood or metal scrap with a roof to
keep
snow and rain off the seeds. Construct sides to the feeder to prevent
birds from
kicking out the seed mixture while searching for their favourite types
of seed.
4. Make another metal bird feeder by cutting out both ends of a
coffee tin, and attaching a cake pan under it with stiff wire. Make a
plastic lid to fit over the top and hang from a branch with wire.
9.7 Butterfly
life
cycle
See diagram 9.7: Butterfly life cycle
Put caterpillars in a box and feed daily on fresh
leaves, e.g. silkworms on mulberry leaves. Observe
and record the development of the caterpillars each day. Record all
changes from caterpillar to cocoon to the fully developed butterfly
phase. Note the time required for the individual phases. Release the
fully developed butterflies.
9.8 Mosquito life cycle, Culex
See diagram 9.8: Mosquito life cycle
1. Collect the different stages of the
mosquito life cycle: eggs,
pupae,
larvae, male and female adults. The eggs
usually cluster together to form a raft. The pupa is unusual because it
can wriggle. Keep the different stages in a large screw-top jar or an
aquarium with a glass top. Put waterweed in the jar
or aquarium. Do not allow adult mosquitoes to fly out and bite people
because of the diseases carried by mosquitoes.
2. The mosquito can most easily be controlled during the
larva stage when it lives in water for a long time. Draining the water
or adding insecticide
to the water kill the larvae and
control mosquitoes.
3. Observe diagrams of the Anopheles
mosquito that carries
malaria fever caused by the parasitic protozoan Plasmodium.
Discuss how to control mosquitoes near the
home.
9.9 Body of cockroach or grasshopper
See diagram 9.9.0: Insect general body plan,
vertical section | See diagram 9.9.1:
Cockroach | See diagram 9.9.2: Grasshopper | See diagram 9.9.3: Mouthparts | See diagram 9.9.4: Wings
Structure of insects
The body is divided
into three regions, head, thorax and abdomen
1. The head, the neck is flexible in predators, e.g. praying mantis
1.1 Compound eye made of separate units (ommatidia) to provide "mosaic"
vision. Each ommatidium has an outer lens, seen as a facet and light
sensitive organ. Number of facets per eye: house fly 4 000 facets,
butterfly 20 000, dragonfly 25 000. Insect eye can detect movement but
cannot focus. Most insects cannot distinguish separate colours but how
colours reflect ultraviolet light. Most insects are attracted to
ultraviolet light. so UV light electric "insect zappers" are found in
food shops. In the head of some insects are three ocelli, structures to
determine
light intensity.
1.2 Mouthparts have 3 pairs of jaws:
1.2.1 Mandibles for biting and chewing, with flap above (labrum) as an
upper
lip
1.2.2 Maxillae can hold food and have sensory palps
1.2.3 Labium acts as a lower lip but may be modified to form long
feeding tubes, e.g. sucking bugs (hemiptera)
mosquito
The mayfly has no mouthparts, so it cannot feed.
1.3 One pair of jointed
antennae, organs of touch and smell.
Mobile filaments made up of segments linked by membranous joints.
Long where sense of touch is important, e.g. cockroach.
Short where sight more important, e.g. dragonfly
End of filament modified as flattened leafy plates, e.g. scarab beetle,
club at end, butterfly, elbowed shape, e.g. ants, feathery branched,
e.g. emperor moth
2. The thorax, 3 segments fused to each other, prothorax pair of
legs, mesothorax
pair of legs, pair of fore wings meta thorax pair of legs,
pair of
hind wings
2.1 Three
pairs of jointed walking legs that end in claws, one pair on each
thoracic segment
Legs modified for digging, e.g. mole cricket, swimming, e.g.
waterboatman, seizing prey, e.g. praying mantis, jumping, e.g. cricket
2.2 Two pairs of wings, if present, are on the second, or second and
third, thoracic
segments
The different arrangements of wings include the following:
2.2.1 Wings membranous flap supported by network of "veins" with
arrangement
characteristic of different insects
2.2.2 All 4 wings are used in flight to beat independently, e.g. dragon
fly or
pairs of wings joined to beat as one wing, e.g. bee, butterfly, moth
2.2.3 Fore-wings are thickened and hind-wings can be folded under them,
e.g.
locust, grasshopper or modified to form protective shield not used in
flight (elytra), e.g. beetle.
2.2.4 House flies have hind wings modified as knobs (halteres).
2.2.5 Flightless insects have no wings, e.g. fleas, lice, some sucking
bugs.
3. Abdomen, 11 segments or less or fused, joined by thin
membrane, no appendages for locomotion on the abdomen
3.1 At apex male genitalia including claspers formating
3.2 At end female egg-laying organ (ovipositor) or modified to
form a sting, e.g. bee, ant, wasp.
3.3 Anus at end with on each side are segmented cerci, like small
antennae,
but they can be modified to form forceps, e.g. earwig.
4. Respiration uses spiracles
laterally situated on some of the body segments and leading into the
tracheal
system of tubes inside
the body.
5. Chitinous
exoskeleton
Exoskeleton (cuticle) made mainly of chitin is hard, strong and
impermeable
Observe
the head, antennas, compound eyes, mouth parts, three pairs of jointed
legs,
thorax, pairs of wings, abdomen, openings along the side of the abdomen
for
breathing, wing veins that support the wings and keep the wings rigid
when flying.
8. Examine the body structure of the cockroach with a magnifying glass.
Hold
a female cockroach with forceps, by one of its legs so that it can be
turned right round and inspected. Repeat the examination with a male
cockroach. Note
the differences between the male and the female cockroaches from both
dorsal and ventral views. Note where the legs are
attached to the abdomen. Note whether the three pairs of legs all
have the same design. Note the
wings attached to the abdomen, the antennas and the two large
eyes
on the head.
9. Examine prepared slides
showing various parts of the head of cockroach or find the mouth parts
folded
under
the head and pointing backwards. Using a fume cupboard, fume hood,
detach the head and
boil it in 5%
potassium
hydroxide solution. Detach the mouth parts with forceps and dehydrate
with methylated spirit in a watch glass, then add some xylol. Make a
circle with a polystyrene mounting medium on a microscope slide.
Arrange the mouth
parts within the circle then put on a coverslip.
Note how the mouth
parts are modified for biting and crushing. Identify the upper lip
hinged to the lower portion of the face, a pair of mandibles (first
pair of jaws) at the sides of the
mouth, a second pair of jaws behind the first pair, and the lower lip.
9.10 Frog life cycle
See diagram 9.310: Frog life cycle
Put a clump of frog spawn the size of a fist into an aquarium. At least
half the
water in the aquarium should come from the place where the frog spawn
was found. The water must be kept clean throughout the period of
observation. When the water becomes cloudy, replace a part so
that it is always clear. Algae will develop on the inside of the
glass providing nutrients for the young frog larvae. Give as much
commercial fish food as the frog larvae, tadpoles, can eat in half an
hour. Remove any food uneaten at the end of this time with the sludge
extractor to prevent it decomposing and clouding the water. Observe the
development of the frog larvae and tadpoles daily. When the tadpoles
have legs, put a small floating piece of cork or foam plastic on the
surface of the water in the aquarium, so that they can leave the
water when necessary. Release the fully developed young frogs when the
observations have been completed.
Note the following:
1. Frog's egg
in the gelatinous capsule
2. Young larva in the capsule
3. Larva with a tail, a young tadpole, that has emerged from the
capsule
4. Large tadpole without legs
5. Tadpole with hind
legs
6. Tadpole with hind legs and forelegs
7. Small young frog
with the remains of a tail
8. Fully-developed young frog
9.11 Study an unfertilized
chicken egg
See diagram 9.11: Parts of an egg
Put a flat transparent dish on black
paper. Break open a hen's egg. Note the yellow yolk and the clear
part called the "white" of an egg because it turns
white when cooked. Find a small white patch on the yolk. In the centre
of
this white patch, too small to see with the eyes, is the germinal disc,
the blastoderm, a sheet of cells that becomes the embryo chicken. The
yolk is a food
store, mainly protein and fat. The yoke is enclosed in a yolk membrane.
The albumen, "egg white", is a solution of mainly the protein albumin.
It is a store of water and protein. The chalaza is one of a pair
of twisted cords of albumin at each end of the egg. It supports
the
yolk centrally within the shell. The shell membrane consists of two
membranes that prevent evaporation of water. At one
end of
the egg the two layers separate to form the air sac that allows the
baby chick
to take its first breath before it breaks open the shell. The shell is
mainly
spongy calcium carbonate.
9.12 Make a cardboard box
incubator
See diagram 9.12 Simple incubator
Use a large and small cardboard box. Cut one end from the small box.
Cut a 15 cm2 window in a side of the large box. Cut a slit
in
the top of the smaller box and suspend an electric lamp in it by a long
electric cord. Put the small box inside the larger box and pack
newspaper
between them. The open end of the small box must fit against the side
of
the large box with the window. Put a thermometer in the box
where it can be read through the glass window.
9.13 Make a Styrofoam cool
box incubator
See diagram 9.13: Electric
incubator
Punch a
hole in the side of a Styrofoam box to
fit a 40-watt light bulb socket. Be careful! The light bulb socket is
an electrical and fire hazard. Keep the incubator away from liquids or
wet areas and out of direct sunlight.
Put aluminium foil on the bottom of the box. Put a piece of wire mesh
across
the box. Be careful! Use safety
glasses and thick gloves when handling wire mesh. Make air holes
in the sides and in
the lid of the
incubator. Also, make a hole in the Styrofoam for a
thermometer.
Maintain
a constant temperature of 38oC in the incubator for 21 days.
Use different sizes of light bulbs and change the lining newspaper to
regulate the
temperature.
Put a dish of water in the incubator to keep the relative humidity at
55%.
9.14
Study the development of the chicken embryo
See: Chicken
project
Obtain fertile
eggs from a chicken or from a poultry farmer with roosters in their
flocks and immediately put the eggs on their sides inside the
incubator at a temperature that should always be close to 38oC.
Eggs sold in stores or supermarkets are usually infertile. The relative
humidity should be 55% so put a pan of water or a wet sponge in
the incubator. Turn the eggs three times a day until day 18 to
stop the yolk sticking to the shell. Put a pencilled cross on the egg
each time you turn it and move the eggs to different places.
Monitor the development of the chicks by "candling". Hold the large end
of the egg up to an electric light in a dark room after the 4th
day of incubation. The egg contents are pink when the embryo is
developing properly. As the embryo grows, it occupies more of the space
within the shell until near hatching it occupies all of the space
except for the air cell. Remove the eggs if they appear clear
(infertile eggs) or if they do not show much development at 10 days
(dead
embryos). The air cell increases in size during incubation
depending on temperature and humidity as moisture evaporates from the
egg. Note the heart of the developing chick already beating by
day 7. After three days,
remove one egg and crack it open carefully. Put the contents
into
a shallow saucer. A three-day embryo will usually show the heart
already
beating. It may continue to beat for half an hour. Remove an egg at day
7 and day 10 to study the development of the embryo. Leave the
remainder of the eggs
for 21 days to hatch. Listen to the eggs during the final 3 days. When
cracks or a little hole appears at day
21,
the chicken is about to hatch. Do try to help
the chick out of the shell even if it takes a day to get out. The chick
cracks the egg with its egg
tooth, a hard lump on its beak. Find the egg tooth in a chick. When the
chicks have dried and become fluffy, remove them from the incubator.
9.15 Measure the eggs
See diagram 9.11: Parts
of an egg | See diagram: 50.6:5: Measure the
egg
Keep records of the eggs during the 21 days to hatching.
Each day do the following:
1. weigh the fertilized eggs,
2. measure the length of
the egg with a pair of callipers,
3. Record the measurement in a table.
Examine the tables and note whether the weight and length change.
Weight is lost when food is broken
down
during respiration to carbon dioxide and water that can both diffuse
out through the egg membranes and the shell.
9.16 Make a warm brooder
See diagram 9.16: Feeders and drinkers,
holding a chick
A hen sits on eggs keeps them warm. When the chickens hatch, they
huddle under the hen for warmth and protection. If there is no mother
hen, keep
the chickens warm with a 100 watt bulb in a brooder. Do not let the
chickens touch the light bulb. Reduce the temperature each week by
3°C from 37°C to 21°C. Give the
chickens
food and clean water. Use shallow dishes for the food and water. Put
sawdust or straw in the brooder to absorb droppings. At
first
give the chickens a handful of chicken mash. Add more food to
the dish each day and always provide clean water. Keep the brooder
clean.
9.17 Study the development
of the hatched chickens
Be careful! Use safety
glasses and thick gloves when handling the chickens
See diagram 9.17.1: Feathers | See diagram 9.17.2: Feathering record
Keep a chicken
diary to record the
weight, height and
behaviour of the chicken each day for the first three weeks.
1. Weigh a newly hatched chicken and record the weight in a
table. Plot a graph of the changes in weight.
2. Use callipers to
measure the height of the chicken from the top of its
head to its feet.
3. Describe
the
change in colour, shape and development of its feathers.
4. Describe
how the chicken
walks
when it first hatches and how this walk changes later.
5. Describe its
"cheep"
cry when newly hatched and how its voice changes later.
6. Describe
how it
pecks at its food, and drinks its water.
9.18 Find the sex of the
chickens
Turn the
chicken over in the palm of the hand
with its head pointing towards you. Be careful! Use safety glasses and
thick
gloves when
handling the
chickens. Try to find the opening
underneath
its tail. Use the thumbs to fold down the feathers. Fold the skin down
around the opening but do not press too hard. If the chicken is a male,
see the penis like a small piece of thread. The chicken is a female if
the penis cannot be seen.
9.19 Insect collecting
Collecting from animals, parasitic insects
Collecting from bark
Collecting from birds' nests
Collecting from carcasses
Collecting from dung
Collecting from emergence boxes
Collecting from flight, only adult insects, use a butterfly net, use a
light trap
Collecting from flowers, shake flowers over an umbrella, also some
small insects inside flower buds
Collecting from foliage, hold an unbrella under foliage and beat the
foliage to dislodge the insects, eggs can also be collected from foliage
Collecting from fruit, keep fruit in a container to allow adyult
insects to emerge
Collecting from fungus
Collecting from galls
Collecting from leaf litter
Collecting from leaves, larvae of leaf miners leave snake-like markings
on the leaves, pick leaf and keep fresh for adult to appear
Collecting from roots
Collecting from soil
Collecting from stones and rocks
Collecting from water, aquatic insects
Collecting from wood, dead wood
9.20 Insect collecting
nets, air net, sweep net
Air net
To make
an insect air net, use a broomstick,
heavy wire and mosquito netting. Bend a
heavy piece of wire into a circle 45
cm in diameter, and twist the ends together to form a straight section
15 cm in length. Fasten this to the end of a broom handle with a wire.
Cut a piece of mosquito netting to form a net 75 cm deep and fasten to
the circular wire frame with stitches. Be careful! Use safety glasses and thick
gloves when handling heavy pieces of wire.
Sweep net
Make a sweep net with muslin
and very heavy wire that
will not bend when the net is swept through grass. Sweep by working
back and forth over a measured area. Count the net contents to estimate
the number of insects between the soil surface and the grass tops. To
find the relative numbers of insects, sample the school grounds, a farm
field, an abandoned field, forest floor or other natural areas. Before
the
sweeping of vegetation, make small
cages for crickets or grasshoppers with metal insect netting. Be
careful! Use safety
glasses and thick gloves when handling metal netting. Put grass, water
and a small dish of moist sand in each cage.
Females
may lay eggs in the sand.
9.21
Insect-killing container
Obtain a wide mouth glass container with a screw
top
or one that closes very tightly. Put a cotton wad in the bottom of the
container and
cover it with a round piece of cardboard or absorbent paper that has
several holes punched through it. When the container is used, saturate
the
cotton wad with an insecticide. Put the piece of cardboard over the
cotton
wad and then put the insect in the jar. Close the container tightly and
leave
until the insect is dead. Use a large container if collecting moths or
butterflies to avoid damaging the
wings.
9.22 Insect stretching
board (setting board)
See diagram 9.22: Insect stretching board
(setting board) | See diagram 9.22.1: Insect
cages
Use an
insect stretching board to prepare
insects for mounting. Make the stretching board from flat cork sheets
or soft
wood split into two equal parts with a space 1 cm wide between them.
Fit the
cork sheets into a flat cardboard or wooden box. Put the body of the
insect in
the space and pin the wings on the top with strips of paper held by
pins pushed
into the cork but not through the wings.
9.23 Mounting boxes for
insect collections
Use wood boxes for keeping
insect collections. After removing the
insect from the stretching board, push a pin or long entomological pin
through the body and pressed into the bottom of the box to hold the
insect. This is called a mounted specimen. Arrange the pins in orderly
fashion. Attach small cardboard cards containing information about the
insects, e.g. name, where caught, date of capture. For displays in a
school museum remove the lid and cover with glass or cellophane taped
to the box to make a permanent mounting. Store soft-bodied larvae and
pupae in tubes containing methylated spirit or other special
preservatives for insects.
9.24 Make a mounting block
guide
A uniformly mounted collection is more
attractive and makes it easy to
compare specimens. Make a wooden mounting block that looks like three
steps. Each step has a hole drilled through its centre. Use the top
step to line up all insects at the same height by impaling the insect
and pressing the pin through the top hole. The other steps provide
uniform levels for labels containing information about the specimens.
9.25 Make a simple insect
cage
Make a 15 cm
cubical frame from ice-cream bar sticks. Pull a ladies
stocking over the frame and close the open end by tying a loose knot.
The open end provides access to the cage interior.
9.26 Make an insectarium
Put 3 cm
of moist, not wet, soil in an aquarium.
Add rocks and a small log. Transplant small plants from the garden.
Catch
insects and put them in the aquarium. Cover the aquarium with wire or
plastic
mesh. Use only 3 or 4 beetles. Remove any leftover food after 3 days
then add
fresh food. Sprinkle the soil with water when it becomes dry. Give
lettuce or cabbage leaves to grasshoppers. Give pieces
of
apple, plums, and bananas to bugs and flies Give bread or fruit to ants
and cockroaches. Give grain to beetles.
9.27 Keep a diary of
insect behaviour
Note when are the insects are
more active, when and how they feed, how they get on with each another,
when
they sleep or rest at night or during the day.
9.28 Collect night insects
Study night flying
insects by
setting up a light trap. It is a white sheet stretched out between
small trees at an angle of 30o from the vertical. Put a
bright light source under the sheet.
9.29
Insect collector
See diagram 9.29: Insect-collector or
"ant-sucker"
Make an insect collector.
Use a 30 cm length of plastic or glass tubing, 3 cm in diameter, a
small piece of fine wire mesh, and a length of flexible tubing. Cut a
circular piece of wire mesh slightly larger than the inside diameter of
the glass or plastic tubing. Force the screen half way through the
tubing by pushing it with a rod.
9.30 Simple animal traps
You may need permission to keep animals in the school. Also you may
have to report periodically on what animals you keep and why they are
necessary for your teaching programme.
Catch small mammals and reptiles for study (not snakes). Use a large
glass container with a wide mouth and a
screw-on cap. Make a one
way door by cutting an opening in the lid and attaching a free swinging
metal door that opens inward only. The door swings on a stiff wire.
Transfer animals to cages without direct handling. Be careful! Wear
heavy leather gloves when handling reptiles or
mammals. Even when non-poisonous, bites from such animals may become
infected.
9.31 Cages
Keep animals in cages in the science room for short periods of
observation. Make a cage from a wooden box with a hinged lid that has a
window
covered with wire netting. Cut windows in three sides of the box. Cover
the side and back windows with wire netting, and a fit a glass plate in
the front window. Add a drawer fitted under the front glass
window and covering the entire bottom of the cage to allow cleaning the
cage without disturbing the animals.
9.32 Food and water
Keep food and water containers above the floor of the cage. Make a
feeding trough for small animals by cutting a section from the side of
a tin can, bending over the sharp edges, and then attaching it to the
side of the cage with wires. Make a watering device for small animals
from a bottle fitted with a one-hole rubber stopper through which
passes
glass tubing. Invert the bottle and insert the tubing through the
screen into the cage. Change food and water daily and clean cages once
a week.
9.33 Earthworm
behaviour, Lumbricus
See diagram 9.33.1
Make a wooden observation box 30 cm X 30 cm X 15 cm fitted with a
glass front to studying the habits of earthworms. Fill the box
nearly to the top with successive layers of 1. sand, 2. leaf mould, and
3. loam soil. Pat down each layer before adding the next layer. Put
lettuce leaves, dead leaves, and pieces of carrot on the surface of the
soil. Loosen the surface of the soil and gently drop on some
earthworms. Watch them burrow into the loose soil. Keep the contents of
the box damp and study the behaviour of the worms through the glass
front of the observation box.
9.34 Ant study
See diagram 9.34.1: Ant observation nest | See diagram 9.34.2: Ant life cycle | See diagram 9.29: Aspirator bottle, "pooter",
"ant-sucker"
Ants (Order Hymenoptera, Family Formicidae)
The life
cycle has four stages, egg, larva,
pupa, and adult. A winged female is fertilized by a winged male in
flight, then
finds a protected place or makes a chamber. She then bites off her
wings and
starts to lay eggs. Fertilized eggs become diploid females and
unfertilized
eggs become haploid males. The eggs hatch into worm-like larvae that
have no
eyes or legs. They eat food collected by the queen or regurgitated by
worker
ants. The larvae moult many times as they get bigger. At full size the
larvae
spin a cocoon around themselves and become a pupa that will change into
the
adult form of ant by metamorphosis. The female worker ants forage for
food and
take it to the queen or to storage. The males soon die but the queen
and
workers can live for many years. The queen controls the activities of
all the
workers or soldiers in the ant nest.
Make an ant observation nest with glass sides and a lid. Cut an entry
hole
near the top of one side and plug it with cotton wool. Collect 100 ants
with an insect-collector (ant-sucker) and put them in a bottle. Fill
the observation nest
with soil from where the ants were collected to the level of the
plugged
hole. To
find the queen, dig
up the earth and put it on a white sheet. Break up the earth with the
fingers and look for one
ant much larger than the others, the queen. Guide
the queen to a second bottle. To get the ants into the observation
nest, fill a
large flat tray with water and put an upturned dinner plate in the
middle to
form an island. Put the observation
nest on the upturned plate and release the ants from the bottle. When
the queen is inside the nest, the
other ants will follow her through the entry hole. Plug the hole then
remove the nest to its permanent place. Put honey inside the entry hole
to provide food, and keep the soil moist. Study the activities inside
the nest. Observe the laying of eggs,
the larvae, and how ants communicate by rapping each other
on the head with their antennas. Artificial light does not
disturb the ants. Observe the activity inside the tunnels parallel to
the glass. Experiment by the removal and subsequent return of a few
ants, and the introduction of foreign ants. When the
nest is settled and the queen starts laying eggs, remove the cotton
wool plug from the hole. Put the observation nest near an open
window and the ants will come and go freely.
9.34.1 Flying ants and
termites
Both
ants (Order Hymenoptera, Family Formicidae) and termites (Order
Isoptera, white ants) can swarm during spring and summer. Swarming is a
natural occurrence that enables the colonies to reproduce and create
additional nests. Flying termites (alates) noticed outdoors should not
normally be reason for alarm, however more than a few swarming termites
indoors may be a far more serious problem. If you notice more than 20
termite alates indoors, i.e. they have not flown in from
outdoors, contact a pest controller without delay. Try to capture and
live specimens in a dry jar. Do not add water or any
preservative. Both flying termites and flying ants have two pairs of
wings and their colour is dark grey to black.
Termites:
1. Have antennae that are almost straight and have a beaded appearance.
2. Wings are virtually twice as long as their body
3. Both wing pairs are the same size.
4. Wing veins are not visible to the naked eye.
5. Have no taper to their body
6. Wings break off easily, with just a touch
Ants:
1. Have antennae that are elbowed (bent)
2. Wings differ in size. The outer pair is larger than the second pair.
3. Have narrow tapered waists
4. Wing veins are usually easily seen with the naked eye
5. Have sturdy wings that do not break off easily.
9.35 Cultures of fruit
flies
See diagram 9.35.1: Male and female Drosophila,
graph of population study
The
common fruit fly, Drosophila, is used
in genetic studies. It is easy to culture and reproduces rapidly, so it
is
suitable for population studies. Put ripe fruit, e.g. a banana, in the
bottom of a
jar and fit a paper funnel with a hole in the end in the mouth of the
jar. Put
the jar in the open. When fruit flies have entered the jar, remove the
funnel and
plug it loosely with cotton wool. The fruit flies should be both males
and females.
The females are larger, with a broader abdomen. The males are smaller
and have
a black-tipped abdomen. The females will soon lay eggs and larvae will
hatch
after two days. Put a piece of newspaper in the jar for the larvae to
crawl on
when they are ready to pupate and change to adult insects. Put
newly-hatched
flies in another jar to start a new generation. Make daily counts of
the
population in the bottle. When numbers become very large, stand a piece
of
graph paper in the jar to count the number of pupae on the grid.
Maintain the bottle as
long as
the fruit flies survive. Investigate the relationship between density
of fly
population,
food preferences, temperature, life span and population.
9.36 Flatworms,
Dugesia, Planaria
See diagram 9.36.1: Flatworms can
regenerate parts
Flatworms react to different stimuli and can regenerate lost parts.
Look for flatworms on the underside of submerged logs or stones in a
pond or lake. Trap them by placing a piece of raw beef liver in cloth,
tying it with a string and placing it in the water. Check the bait
daily, and brush off any flatworms into a small jar of the water where
they were living. In the classroom, use a medicine dropper to transfer
them into a flat enamelled pan. Keep the pan covered with a piece
of brown cardboard when not observing them. Once a week feed the
flatworms with finely chopped liver, or hard-boiled egg, or bits of
worms. Remove uneaten food with a medicine dropper after three hours.
Note how flatworms respond to various stimuli, e.g. light, sound, food,
mild electric shocks and Epsom salts. Use a magnifying glass to observe
the tube-like pharynx with which the flatworm uses to ingest its food.
A flatworms can regenerate parts if you put it on a glass microscope
slide and cut it with a sharp razor blade. Cut it in half across the
body or down the length of the body. A cut part-way down the midline of
the body can produce a worm with two heads or two tails. After cutting
the flatworm, return the parts to the dish and do not feed until
regeneration has occurred.
9.1.2 Insect collection
1. Insect collecting net, air net
See diagram 9.22.1
To make an insect air net use a broom stick, heavy wire and mosquito
netting. Bend a heavy piece of wire into a circle 45 cm in diameter,
and twist the ends together to form a straight section 15 cm in length.
Fasten this to the end of a broom handle with a wire. Cut a piece of
mosquito netting to form a net 75 cm deep and fasten to the circular
wire frame with stitches.
2. Insect collecting net, sweep net
Make a sweep net with muslin and very heavy wire that will not bend
when the net is swept through grass. Sweep by working back and forth
over a measured area. Count the net contents to estimate the number of
insects between the soil surface and the grass tops. To find the
relative numbers of insects, sample the school grounds, a farm field,
an abandoned field, forest floor or other natural areas. Before the
sweeping of vegetation, make small cages for crickets or grasshoppers
with metal insect netting. Put grass, water and a small dish of moist
sand in each cage. Females may lay eggs in the sand.
9. Insect killing container
Obtain a wide mouth glass container with a screw top or one that closes
very tightly. Put a wad of cotton in the bottom and cover it with a
round piece of cardboard or absorbent paper that has several holes
punched through it. When the container is used, saturate the cotton
with an insecticide. Put the piece of cardboard over the cotton and
then put the insect in the container. Close the container tightly and
leave until the insect is dead. If moths or butterflies are being
prepared, ensure that the container opening is large enough to avoid
tearing the wings.
4. Mounting boxes for insect collections
Use wood boxes for keeping
insect collections. After removing the
insect from the stretching board, push a pin or long entomological pins
through the body and pressed into the bottom of the box to hold the
insect. This is called a mounted specimen. Arrange the pins in orderly
fashion. Attach small cardboard cards containing information about the
insects, e.g. name, where caught, date of capture. For displays in a
school museum remove the lid and covered with glass or cellophane taped
to the box to make a permanent mounting. Store soft bodied larvae and
pupae in tubes containing methylated spirit or other special
preservatives for insects.
9.1.7 Honeybee body structure, Apis
mellifera
See diagram 9.7.1 Make a paper frame to
study honeybees
1. Examine the hairs on the legs
Cut a piece of paper the size of a coverslip from a sheet of writing
paper and fold to form a two layered triangle. Cut from this triangle
the area so that only a strip 2 mm wide remains. Unfold to give a small
paper frame. Holding it with forceps, preferably at one corner, put a
very thin layer of all purpose glue on both sides and attach it to a
slide. Examine a bee. It can be seen with the naked eye, and even
better with a magnifying glass, that the body of the bee is almost
completely covered with hairs. Pluck a clump of hairs from a well
covered site with forceps. Put it inside the fixed paper frame on the
slide and press a coverslip over the upper side of the frame which is
already coated with glue. The hairs are now firmly enclosed between the
slide and the coverslip. Such a specimen keeps for a long time and is
called a permanent preparation. Permanent preparations can also be
prepared with other specimens by this method. However they must be
absolutely dry as, for example, the scales of butterfly wings. If the
specimens are moist, they go mouldy in the enclosed space between the
slide and the coverslip. Inspect the preparation with a microscope,
magnification 50 X. the hairs. When collecting pollen, bees often roll
over in the flowers, thus covering their whole body with pollen. The
hairs are adapted to the activity of pollen gathering.
2. Examine the antennas
Count the number of parts making up a single antenna and note their
relative arrangement. Examine the antennas with a magnifying glass. The
segment attached to the head is called the scape. A flagellum
consisting of individual joints projects from one corner. Count the
joints in the female worker and the drones. Between the shaft and
flagellum is a small, ring shaped connecting piece called a turning
joint. Transfer a drop of glycerine to the middle of a slide with a
glass rod to examine the dark coloured sections of a bee. Use forceps
to remove both antennas from a bee at the point where they are attached
to the head. Put them in the drop of glycerine on the slide and place a
coverslip on top. Avoid trapping air bubbles by holding the sides of
the coverslip with thumb and index finger and mount it at an angle.
Then draw it into the glycerine drop and let it settle gently into
place without applying pressure. First examine the preparation under a
microscope, magnification 50 X. The structure of the antennas can be
seen more clearly than with a magnifying glass. Round pores are visible
on their surface. Where and how are they distributed? How large are
they? The pores can be seen in more detail using a higher powered
objective, 40 X. The large pores are the openings of the olfactory
pits, and very fine probing setae emerge from the smaller ones. Prepare
a drawing showing the component parts of a bee antennas. What purpose
do the antennas of the bee serve?
3. Examine the wings
The three main sections of the body of a bee are head, thorax and
abdomen. The wings are attached to the middle section, the thorax.
There are two pairs of wings, one pair each of fore wings and hind
wings. Discover how the wings of the bee are constructed. Choose a bee
which has all its wings present, undamaged and not twisted. Hold the
bee between the thumb and index finger of the left hand so that its
back faces upwards and its head points forward. Using forceps, grasp
the outermost tip of the right fore wing and bend it backwards over the
surface of the hind wing. Then draw it slowly forward again. The
trailing edge of the fore wing should graze over the surface of the
hind wing. What can you see? Repeat the process again, if necessary
several times until something attracts your attention. Next, examine
the wings with a magnifying glass. Are they all the same size? How are
they constructed? Using pointed scissors cut off both wings on one side
as close as possible to the body. Transfer a drop of glycerine to a
slide using a glass rod and introduce the wings into it and place a
coverslip over them. Examine the preparation under a microscope,
magnification 50 X. What can you see on the wings? How are they
constructed? Very examine the middle part of the front edge of the hind
wing. What do you find there? There is a brown strip in this middle
section. It is wider than the "veins" of the wing, runs close to the
edge and stands out clearly. At this point the skin of the front wing
wraps over, making a fold. Together with the little hook, hamuli, on
the hind wing it forms the coupling apparatus which is essential for
flight. What is the function of the coupling apparatus of the bee?
Remember what happens when the front wing is drawn forwards over the
surface of the rear wing.
4. Examine the legs
The bee has three pairs of legs. Like the wings, they are attached to
the middle section of the body, the thorax. Examine the legs of the bee
to discover how they are constructed. With the lancet form dissecting
needle tease off all the legs of the bee flush with the body. Be sure
that the legs are completely detached and that nothing remains hanging
from the body. First examine them under a magnifying glass. It can be
clearly seen that each leg consists of several different sections. The
uppermost portion attached directly to the body is the coxa. Then
follows the trochanter, the femur, the tibia and the tarsus, which
consists of five tarsomeres or tarsal joints. The first, uppermost,
tarsal joint is much larger than the other four. The claws are attached
to the last, lowest, tarsomere. How many claws are there? See whether
all the legs of the bee are constructed in this way. What is the hair
pattern? The hind legs of the bee are collecting legs. Examine them
closely to see why they are called this. On the inner side of the first
tarsal joint are transverse rows of stiff hairs like bristles. They can
be clearly seen with the magnifying glass. They form the pollen brushes
with which the bee brushes off the flower dust, or pollen, from its
body. Count the rows of bristles. On the outer surface of the tibia
there is a smooth hairless area which is slightly concave. This
depression is called the corbicula, or pollen basket. It is used for
storing pollen. Hairs surround the edge of the basket. What is their
shape? And how are they arranged? In what direction do they point? What
do they do? Using a glass rod place a drop of glycerine in the middle
of a microscope slide, place a collecting leg in the glycerine and
place a coverslip over it. Examine the specimen under the microscope,
magnification 50 X. The enlarged image shows the pollen press situated
at the junction of the first tarsal joint and the tibia. The pollen
press packs the pollen into small clumps which are then deposited in
the corbicula. This is how bees "breeches" are formed. What does the
pollen press look like? Prepare a foreleg from a bee in the same way,
and also examine it at magnification 50 X. The fore legs are the
cleaning legs of the bee. At the upper end of the first tarsomere is a
semicircular depression, or notch, fitted with fine setae like a comb.
This is called an antenna cleaner. At the lower end of the tibia there
is a lateral jointed spur, the fibula. When the bee bends the first
tarsomere towards the tibia, the fibula closes the cleaning notch. The
bee then draws its antennas through the comb to remove any adhering
pollen grains. Which legs of the bee are used for cleaning and which
for collecting? Where are the brushes and the corbicula found on the
collecting legs? Why does the bee clean its antennas with the antennas
cleaner?
5. Examine the sting apparatus
Only female bees, both workers and queens, possess a sting apparatus,
which is situated in the end segment of the abdomen. It is used as a
weapon. Examine the structure of the sting apparatus of the bee.
Transfer a drop of water from a beaker to a slide with a glass rod. Put
a bee on its back on a ground glass screen and hold it firmly at the
front end of the abdomen with either forceps or your fingers. Place a
pointed dissecting needle on the centre of the abdomen and stroke it
backwards, pressing gently. The sting will be pressed out of the
abdomen, usually with the first stroke. Take hold of it with the
pointed forceps, draw it out from the abdomen together with all the
adhering organs and place the whole in the drop of water of the slide.
Mount a coverslip over it and examine the specimen under a microscope,
magnification 50 X. The sting is clearly visible. What shape is it? And
what colour? If it has been arranged in a useful position barbs can be
seen at the tip of the sting on both sides. In which direction do the
tips of these barbs point? And why? At the upper end of the sting is a
swollen sac-like structure from the other end of which hangs a long
thin thread. If removed undamaged from the abdomen this thread will be
seen to be divided into two short branches. These two threads are the
venom, or "acid", glands. The venom released from them then passes, for
storage, into the swelling which is called the venom sac. On either
side of the sting lie various plates and muscles which are used when
the bee injects the sting into the body of its victim. All these parts
collectively form the sting apparatus of the bee. the constituent parts
of the sting apparatus? What is their relative arrangement?
9.20 Flatworm behaviour, Dugesia,
Planaria
Flatworms react to various stimuli so they are suitable for simple
studies of behaviour. They also possess an ability to regenerate lost
parts.
1. Finding and feeding flatworms
Look for flatworms on the underside of submerged logs or stones in a
pond or lake. The best species for study are the brown Dugesia or the larger Planaria. Trap them by wrapping a
raw liver in cloth, tying
with string and putting it in a pond. In the classroom, transfer the
flatworms with a large medicine dropper into a bowl. Keep the
containers covered with a lid when not observing. Feed finely chopped
liver, hard-boiled egg, or bits of worm once a week. After 3 hours
remove excess food with a medicine dropper.
2. Flatworm behaviour
Observe how flatworms respond to light, sound, food sources, mild
electric shocks and chemicals, e.g. Epsom salts (magnesium sulfate
crystals). Use a magnifying glass enables to see the tube-like pharynx
with which the flatworm ingests its food.
9. Flatworms regenerate parts
Flatworms can regrow parts if you put a specimen on a glass slide and
cut it with a sharp razor blade. Cut worms in half across the body or
down the length of the body. A cut part way down the mid line of the
body produces a worm with two heads. After cutting, return the parts to
the dish and do not feed until regeneration has occurred.