Gloucestershire Wildlife Trust Life Cycles Objectives To know what a life cycle is. To recognise and sequence the different stages in a life cycle. To appreciate that a life cycle is dependent on certain factors, such as food and the correct environment. To know that there are different kinds of plants and animals in the immediate environment, and learn more about them. To be able to treat animals and the environment with care and sensitivity. Year Group Years 1 and 2 (5 to 7 years) uration 1½ to 2 hours National Curriculum Objectives KS1 Science (Sc1/2efh; Sc2/1, 2abefg, 4b, 5abc) Preparatory Work Key Words Undertake a site visit (remember your wellies!) and risk assessment (a sample risk assessment is provided). Ensure that the site is suitable, that facilities are adequate, that people are expecting you and you have permission to be there. Equipment Be especially sure that the river is suitable for dipping (shallow bank and water, stony bottom, without areas of deep silt or mud). Gather together the equipment needed (as set out below) and download, print and laminate (if desired) the supporting material keys, recording sheets, life cycle sheets and worksheets if necessary. Plants Animals Life-cycle Egg Larva Nymph Adult Immature RSPCA Frog life cycle pictures and explanations (one per group) which can be found at: http://content.www.rspca. org.uk/cmsprd/satellite?blobcol=urldata&blobheader=application %2Fpdf&blobkey=id&blobnocache=false&blobtable=MungoBlobs &blobwhere=1232992293251&ssbinary=true RSPCA Ladybird life cycle pictures and explanations (one per group) which can be found at: http://content.www.rspca.org.uk/ cmsprd/satellite?blobcol=urldata&blobheader=application%2fpdf &blobkey=id&blobnocache=false&blobtable=mungoblobs&blobw here=1232995933665&ssbinary=true You can also use the twinkl.co.uk supporting material for butterfly and ladybird life cycle activities: http://downloads.twinkl.co.uk/res_downloads/ minizapijeous69/t-t-016-butterfly-lifecycle-worksheets.pdf and http://downloads.twinkl.co.uk/res_downloads/ minizapijeous69/t-t-1083-ladybird-life-cycle-worksheets.pdf Rivers Trust mayfly life-cycle diagram (laminated) A number (one per group) of standard 1mm mesh pond nets A number (at least one per group) of white, plastic examination trays (or something else that will serve the purpose. White surfaces are much easier to identify invertebrates in than transparent ones, although white paper beneath could be used if need be). Recording forms, clipboards and pencils Identification keys Bug pots for examination of individual specimens Wellies!
Lesson Content TIMES ACTIVITY 5 minutes Introduction Preparatory work at school Ask the children what they understand by the word animal, plant and life cycle, and extend to asking them to suggest animals that might go through different stages of a life cycle. Prompt towards recognisable examples like frog or butterfly. Can the children name the different stages in a butterfly s life cycle? Can the children name the different stages in a frog s life cycle? Start by introducing the site and explain briefly what they will be doing during the session. Inform the children of risks with a health and safety talk. Ground rules about boundaries and how to behave near the river. 10 minutes Frog and ladybird life cycles The object of this activity is to help the children to describe and recognise the different stages in a life-cycle, and how to sequence them. In your groups (of not more than five), first ensure that you are all a safe distance from the river bank and give each group the six pictures of a frog s life-cycle. Ask them to cooperate with each other and put these pictures into the correct order. Then adult helpers can read out the explanation cards of what happens in a frog s lifecycle and ask the groups to match these to the pictures. Repeat this exercise with the ladybird life cycle example. 15 minutes Comparing terrestrial and aquatic life cycles The aim of this introduction is to familiarise pupils with different kinds of life cycle, some of which will be familiar, others not. ifferent kinds of animal have different life strategies, related to different environments. Whilst sitting close the riverbank, ask the children to watch carefully for dragonflies, damselflies, mayflies and butterflies. Talk about how the life cycle of a butterfly differs from that of a dragonfly (or damselfly, mayfly or stonefly). Whereas a butterfly lays eggs on land, which hatch into caterpillars, which turn into pupae and then adult butterflies, the other species mentioned lay their eggs in water and have a nymph stage before leaving the water and becoming adult flying insects. NB Nymphs are not quite the same as larvae. Insects that go through a nymph stage metamorphose gradually and generally resemble their adult stages. Larvae go through a pupal stage prior to metamorphosis. Caddis flies have larvae whereas mayflies, dragonflies, damselflies and stoneflies have nymphs! Show the children the life cycle of the mayfly (provided) and talk through the stages. Ask the children to describe the river for example; wet, cold, fast or slow, and ask them to predict what mini-beasts they think they will find in this habitat. Inform them that they will now look for the larval and nymph stages of river mini-beasts (such as mayflies, caddisflies, damselflies and dragonflies) in the river.
Lesson Content TIMES ACTIVITY 50 minutes Stream/river dipping for mini-beasts 10 minutes Plenary Follow-up activities The aim of this exercise is for children to get a good look at river mini-beasts and at the larval/nymph stages in the life cycles of some of our river invertebrates. It will also give them an idea of just how much life there is in such habitats, and how varied it is (depending on the cleanliness of the water). For this part of the day, adults can enter the river to perform disturbance samples with the nets (which the children can then identify on the bank), or children can be allowed to enter the river, depending on the suitability of the river bed, banks and water depth. This decision can be made on the site visit. Remind pupils of health and safety considerations if they are to enter the river. If the children are to enter the river, ensure that they are accompanied by adults, that only one child from each group is in the river at any one time, that the water is shallow and that the river bed is solid. Also be vigilant that children are not straying from safe areas or damaging the banks or in-stream vegetation. An adult should demonstrate the best method of dipping, as follows: Place the pond net on the riverbed and disturb (with foot or hand) the area just upstream of the net for about a minute. The animals will then be carried downstream by the current into the net. Emphasise that you are being careful not to uproot or disturb aquatic plants (as far as possible) as you do this. Fill your white tray with river water to a depth of a couple of centimetres and then lower the net into the water in the tray, carefully turn inside out, and shake gently, to release the contents for examination. If there is a lot of silt in the net, it may be necessary to rinse the contents by moving the net from side to side in the flowing water of the river. Part of this exercise is to engender respect for the natural environment and animals and plants within it, so it is vital to emphasise that animals are to be treated gently and returned safely to the water afterwards. Captured invertebrates (and fish) can be studied and identified using the keys and mayfly nymph identification sheets (adult help may be needed here). Individual specimens can be examined in bug pots if necessary. Finds can be recorded by pupils on the River ipping Recording Sheet, either just as ticks or with numbers also. It may be preferable for an adult supervisor to do this, or, for younger children, to abandon this recording element. uring this time children should also keep an eye out for the adult stages of some of these creatures. Bring the class back together and discuss with them the different mini-beasts that were found. Ask them what animals might eat these creatures (e.g. fish) and what animals might eat the predators of the mini-beasts (e.g. herons, kingfishers, otters). Talk to the class about the human life cycle. With input from the children, go through the stages egg, embryo, baby, child, adolescent, adult, old age. The life cycles worksheet (provided) is a chance to reinforce lessons learnt at the river. Use the Wild Trout Trust s Mayfly in the Classroom activities and teachers notes to rear and release your own river invertebrates http://www.wildtrout.org/index.php?option=com_content&task=view&id=340&itemid=318
Life Cycles River ipping Recording Sheet (KS1) Team: ate: School: River: Species Backswimmer Blackfly larva Bullhead Cased caddis fly larva Caseless caddis fly larva Cranefly larva Crayfish amselfly nymph ragonfly nymph Flatworm Freshwater limpet Freshwater shrimp Leech Mayfly nymph Midge larva Minnow Mosquito larva Pea mussel Pond skater Stickleback Water beetle Waterboatman Water hoglouse Water mite Water scorpion Water stick insect Whirligig beetle Worm species Tick if seen Total
Life Cycles Mayfly Nymphs Mayfly nymphs are tiny insects that live in our rivers and streams. Mayfly Nymphs can be as small as 3 or 4 millimetres long up to over 30 millimetres long, and can live for as long as three years. Generally there are three types of mayfly nymphs 1 Crawling Mayfly Nymphs live under stones in fast flowing rivers and streams. They have flattened bodies so that they are not swept away by the force of the river and they feed on tiny bits of plants and leaves which fall into the river. They breathe oxygen from the water using feathery gills along the sides of their bodies. Also on Swimming Mayfly nymphs. 2 Swimming Mayfly Nymphs have streamlined bodies which are specially adapted for swimming in both fast and slow flowing rivers. They swim around among the stones and gravel of the river bed feeding on tiny bits of leaves and plants. Swimming Mayfly Nymphs also breathe through feathery like gills along the sides of their bodies. 3 Burrowing Mayfly Nymphs have very strong legs for digging the burrows in the fine silt or gravel of the river bed in which they live. They also feed on tiny bits of plants and leaves. Their gills are on their backs and covered by hard cases to prevent them from clogging up with the fine silt of the river bed.
Life Cycles The Life Cycle of a Mayfly Mayfly eggs can be found on the undersides of stones. The eggs hatch into mayfly nymphs There are two stages to the adult mayfly s life. It changes from the nymph into a dun, and then sheds its skin turning into a proper adult called the spinner. An adult mayfly can last from a few hours to a few weeks. uring this time they do not feed - they only mate and lay eggs before dying. The mayfly nymph lives in the water feeding on tiny bits of plants and leaves for up to three years. It sheds its hard outer skin as it grows larger. ifferent species of mayfly nymphs change into adult mayflies during different months of the year and not just May!
Life Cycles Worksheet 1 What would happen to species of animals and plants if they did not reproduce? 2 What is the name for the stage in a mayfly or caddis fly s life cycle before it becomes an adult? 3 Put this butterfly life cycle in the right order: butterfly egg caterpillar pupa a. b. c. d. 4 What is the first stage in the life cycle of a mayfly or a frog? 5 What is the first stage in the life cycle of a human? 6 Put these stages of the life cycle of a human in order: old age adolescence child adult embryo egg baby a. b. c. d. e. f. g.
Life Cycles Freshwater Minibeast Identification Chart Swimming mayfly nymph (up to 11mm) Squat mayfly nymph (up to 7mm) Three tails, six legs similar to swimming mayfly but often has silt/sediment coating giving a scruffy appearance. Flattened mayfly nymph (up to 16mm) Burrowing mayfly nymph (up to 40mm) Flat with moon shaped head, six legs and three tails. Crawls rather than swims. Six legs and three tails. Long brown body with two rows of feathery gills along its back. amselfly nymph (up to 30mm) ragonfly nymph (up to 70mm) Stonefly nymph (up to 30mm) Cased caddis larva (up to 55mm) Three flattened tails. Body moves from side to side when swimming. Usually green or brown. Three short tails (prongs) and six legs. Crawls. Six legs and two long tails. Crawls slowly. Gills not usually obvious. Lives in a case of sand, stones, twigs, pieces of leaf. Crawls, dragging its case. C2 C2 Caseless caddis larva (up to 26mm) Alderfly larva (up to 40mm) Blackfly larva (up to 15mm) Cranefly larva (up to 30mm) Six legs. Usually a dark head and a paler body. Two small hooks at the tail end. Long gills trail from side of body. Stout brownish body with a single tail. End of body swollen. Moves by looping. Often attached to stones by a sucker. Grey, maggot-like appearance C2 Non-bitting midge larva (up to 20mm) Worm (up to 40mm) Flatworm (up to 40mm) (Blood worm). Bright red or green. Swims by flicking its body in a figure eight shaped movement. Like a small earthworm. ull, reddish brown colour. Rat-tailed maggot (up to 55mm) Grey, fat body and very long tube to breathe air at the water s surface. Leech (up to 30mm) Water snail (up to 50mm) Freshwater limpet (up to 20mm) Pea mussel (about 15mm) Segmented body with a sucker at each end. Moves by looping or swimming. ard shells which may be coiled or spiral. Many types. Small cup-like shell which is steeper on one side than the other. White/grey shell, hinged on one side a bit like a seaside cockle shell. Water beetle (variable size) ard wing covers, meeting in a line down the back. Beetlelike appearance, swimmers or crawlers. Many types. Water boatman (up to 17mm) Pond skater (18mm) Water hoglouse (up to 12mm) Back two legs enlarged to form paddles. Swims rapidly through the water. Black body. Skates on the water surface Greyish-brown, flat, like a woodlouse. Crawls C2 C2 Freshwater shrimp (up to 20mm) Water mite (2 or 3mm) Swims on its side very quickly. Colour varies from reddish to grey. Round body, spider-like. Swims rapidly, very small. Three tails, torpedo shaped body. Swims rapidly through water. Row of gills down each side of body. Very flat, sometimes has horns or eye spots. Glides over stones. Feeding levels key: C2 etritivore erbivore First order carnivore Second order carnivore