Pond animals

Edge and just watch in the spring and summer NES can often be seen swimming about or coming to the surface to take in air stickle backs may be hard to find because their camouflage makes these fish difficult to see when they are not moving the whirly gig beetle is an interesting animal to watch as it spins around and around however a great many Pond animals are hidden in the weeds or in the mud you need a strong net to catch them a quick movement helps keep the mouth of the net from becoming clogged with weeds when the water has drained away we can see what has been caught here is a large water boatman an insect about 1 1/2 cm in length it's best to transfer the animals we want to study into Wide Mouth Jars half filled with pond water small delicate animals which might otherwise be eaten can be put into smaller bottles it's important not to put too many specimens in each jar or some of the Gill breathing animals will die back in the laboratory the bottles and jars can be emptied into white dishes this is a good way to observe animals which might otherwise be hard to see but it is important to keep carnivorous species completely isolated such an animal is the water boatman seen here cleaning its powerful swimming legs the small planarian worms are also carnivorous what can happen when carnivorous animals are not isolated is this a damsel fly nymph is firmly in the grip of a water scorpion Pond snails though feed on plant material these together with other animals can also be studied in an aquarium the Great Pond snail grows up to 5 cm in length and can often be seen browsing on the weeds it takes air directly into its mantle cavity the inner wall of which is well supplied with blood vessels and acts as a kind of lung see how it opens its breathing aperture when it comes up to the surface this is the great Rams Horn snail a large species of Rams Horn like the Great Pond snail they may Harbor many parasitic worms some of these can be seen at the base of the near tentacle and on the side of the head water fleas are fascinating animals to watch and they can be found in Still Water where there are single cell plants for food this is the brown Hydra it captures small animals like water fleas with its tentacles which have many stinging cells Hydra is most easily found if floating Pond wheed is collected and allowed to settle in dishes when undisturbed it will extend to its maximum size the Lesser water boatman feeds on the bottom of the pond by sucking up pieces of debris but to renew its supply of air it has to swim to the surface here the carnivorous greatwater Boatman is devouring a pond skater the damsel fly nymph breathes by means of the three gills protruding from the tip of the abdomen it feeds on small animals by shooting out a hooked structure called a mask from under its chin watch how it catches a water flea the action is very quick watch again back at the pond the adult damsel flies are hatching out and drying their wings in the sunshine but in the water there are enormous numbers of microscopic organisms that we have not yet seen to catch them we use a special muslin net with a jar attached to the base as the net is moved gently through the water and drained these organisms are concentrated in the jar below the contents can then be easily collected it's also a good idea to collect a little of the plant debr from the bottom of the pond because many animals live there to see what we have caught let's go back to the laboratory first let's examine a drop of water from the top of the jar we need a pipet to extract the sample a microscope slide and a cover glass then we can look through the microscope using the low power objective lens first these are single cell organisms called flagellates some are animall likee some plant-like what will they look like under high power they swim by lashing a long hairlike structure called a flagellum the color of these flagellates is caused by chlorophyll which is present in all green plants this flatulate is composed of a plate of 16 unicellular units each bearing a pair of flagella a sample from the debris reveals different species such as this nematode worm decomposing debris also attracts many unicellular animals called protozoa one of the largest of these is spym which may reach a length of 2 mm another is stentor it feeds by drawing a current of water into its gullet you can see the hairlike cyia on stentor which produce the current inside are several flagellates which it has recently caught these are gradually digested in food vacuoles another animal which may be found in the debris is amoeba this particular species is very small but you can see how it moves by producing false feet or pseudopodia closely related to aeba is this animal called dlua the pseudopodia protrude from a thin shell which becomes covered with sand grains and other particles here is a close view of part of the shell small bristle worms are also so commonly found among the debris they are related to the earthworms and feed on decaying plant matter because they are so transparent it is relatively easy to observe the contractions of the intestine and to see the way in which blood is circulated through the body here are many small protozoa moving up and down several filaments of a plant a green alga the Bell animal or vorticella is always found attached to the stems or leaves of water plants here is one in the process of division like stentor vorticella creates a feeding current with its cyia drawing particles toward itself the last Pond Animal we will look at is this brightly colored might related to the spiders although we have only been able to see a few of the animals found in ponds there are many opportunities for further study next time you go to a pond take a net with you and see what you can find out for [Music] yourself