Life In A Pond (1949)

at home perhaps like this group let's go along with this group and find out Maude will find that the pond is the home of a self-sustaining group of plants and animals these plants and animals share the same surroundings from which they obtain the necessary things for living the most plentiful of the living things are green plants we can recognize three different types simply by observing where they grow growing near the shore our shoreward plants their leaves are above the water and their roots are in the bottom of the pond close by our plants on the surface of the water clothing plants beneath the floating plants are those that live under the water these are the submerged plants without green plants the pond could not support animal life for green plants are the basic food supply for large and small pond animals what are some of the smallest animals in the pond can we see them in the pond water let's find out an ordinary glass jar is a good container for collecting small specimens and the hand lens will help us to discover some of the tiny plants and animals this is a hydra one of the common pond animals the hydra is about a quarter of an inch long the water flea is about the same length great numbers of water fleas are the food of fish and other animals water fleas in turn eat tinier animals animals so small that we can see them only with a microscope microscopic plants and animals of many different kinds are the basic food supply for pond animals as we look over the pond we can see larger animals for instance these insects these are small beetles and as we watch them darting and curling above we can understand why they are called koala gig beetles they usually stay on top of the water on the surface film but they also travel on the underside of the surface film here just beneath the surface film are some snails these common animals eat green plants in turn snails are a favorite food of fish and other larger pond animals under the water too will find different kinds of insect larvae these are mosquito larvae suspended from the surface film mosquito larvae breathe air which they get by poking their breathing tube up through the surface film do you see how we can kill mosquito larvae by spraying oil on the water a film of oil keeps them from getting air mosquito larvae are not rapid swimmers so they are an easy prey for larger animals that live under the water such as dragonfly nymphs watch the Dragonfly nymph a good catch we can see the small mosquito larvae inside the mouth of the dragonfly dragonfly nymphs feed only on other small animals they are able to catch live prey with the help of the lower lip which can be extended like a small scoop the Dragonfly nymph is one of the most ferocious of the many different insects will find in a pond this one doesn't hesitate to attack a small fish here's an example of both the struggle to get food and the struggle to avoid being eaten the Dragonfly is one of the many insects that spends part of its lifecycle underwater after about a year of underwater life wings begin to develop and the nymph climbs up out of the water to enter the adult stage of insect life if we watch carefully we'll see the successive stages as the dragonfly comes out of the nymph case now the dragonfly is completely out of the nymph case after a while the four wings open and stiffen and the dragonfly takes to the air we'll see these flashing darting insects skimming over the pond in the bright sunlight for a dull fraggin flies the pond is still a source of food where they may catch and eat adult mosquitoes that emerge from the water and the water is also the place where the female dragon fly lays her eggs starting the life cycle all over again the life cycle of many pond insects follows the pattern of the dragonfly this is the nymph of the mayfly light dragonflies mayflies spend part of their lifecycle underwater if we dredge along the shore of the pond with a dip net we may bring up nymphs of the mayfly or dragonfly these nymphs about an inch long are those of the mayfly what other kinds of underwater animals might we bring up in our net here is a tadpole a large diving beetle and a minnow this diving beetle is one of the biggest of the pond insect it's easy to see why it is called a diving beetle here along the bottom of the pond are tadpoles if we observe them over a period of time during the summer we'll see some interesting changes this young tadpole has a long tail after a few weeks two rear legs develop still later the tadpole has poor legs and finally he comes out of the water as a full-grown frog what does the Frog find to eat sitting on a floating leaf in the pond the Frog watches for insects here's a mayfly insects such as May flies and mosquitoes are food for the Frog sometimes insects such as the mayfly fall on the surface of the pond beneath the surface are large and small fish that may react to a mayfly like this of course minnows and other small fish are a source of food for the larger fish and so the problem of getting food is an important part of life in a pond in studying this life we've seen certain food relationships among some of the common animals that live in different parts of the pond there are many more plants and animals in the pond that we can observe and study and many more examples of relationships between the plants and animals that share the pond we to sometimes share in these plant and animal relationships some of the larger fish for instance are super eyes the abundance and variety of living things the changes in their development and the food relationships among different forms of life these are ideas we can better understand by our study of life in a pond [Music]