Life In A Drop Of Water (revised, 1973)

[Music] the world we live in is a familiar world but the life we can see is not the only life around us life also exists on a much smaller scale in the waters of our lakes and ponds water like this just taken from a pond contains plants and animals so small that we'll look for them in a single drop of water the drop is a miniature world a world that can be entered only through the microscope which will magnify drop many times we can get an idea of what this means from this needle in our everyday World a needle is very small but when we put it into our drop of water under the microscope it looks immense here is a world in which darting animals are smaller than a needle point this is the miniature world of the microscope showing life in its simplest forms these tiny living plants and animals carry on on every one of the fundamental processes of life like all living things each must obtain food to produce growth and energy each moves either from place to place or within itself reacts or responds to changes in surrounding conditions and reproduces its own kind in pond water much animal life depends on simple plants for food these single cell desmids and Dions are common green algae with the aid of sunlight and a green substance called chlorophyll these plants make their own food from minerals water net is another green algae which is an abundant food supply for pond life amiba the simplest one-celled animal has no definite shape it is a tiny bit of jelly-like material called protoplasm the moving living mass is held together by an outside layer of denser protoplasm a contracto vacu looking like a white bubble acts as a pump to collect and expel waste liquids food is absorbed directly into the protoplasm on the left a tiny animal is being entrapped by two of the pseudopods or false feet of the amoeba the color of an amoeba varies depending much upon its last meal the green stem in the lower right is Spyro Gyra a common water plant Vampirella a species of amoeba feeds on Spyro Gyra with needle-like pseudopods Vampirella breaks open the Spyro Gyra cells and extracts the green ribbons of chlorophyll often strands of Spyro Gyra are linked by small bridges of protoplasm this is conjugation the simplest type of sexual reproduction the protoplasm from two cells unites to form a new cell the round object surrounded by Spyro Gyra is volvox volvox like Spyro Gyra has chlorophyll but like amoeba or any typical animal it moves about vvox is really a colony of thousands of single cell plant animals called protests each cell has two small whips of protoplasm or flagella which lash about rolling The Colony over and over more efficient movement is carried on by parium the slipper animal a cell membrane gives parami a definite shape the membrane is covered with cyia tiny hair-like projections moving rapidly the cyia literally Row the streamlined animal through the water parami feeds on the tiniest of plants which are swept in by extra strong cyia lining the mouth Groove parami can reproduce sexually by conjugation or by fision which is simply splitting too other simple animals reproduce by fision like parium these Bell animals are one- cell ciliates but they live attached to plants and stones and do not use the cyia for Locomotion their Celia are specialized for feeding they can be seen as a ring around the open end of the bell-shaped body the rapid beat of the cyia creates a Whirlpool which sucks food particles into the gullet or throat vorticella is named for this characteristic Whirlpool or Vortex the body is on an elastic stalk which anchors the animal to plants or stones in its feeding ground the slightest disturbance causes a reaction like a coiled spring a giant of the microscopic world is stentor the trumpet animal its single cell May stretch out to one tenth of an inch like parium its body is covered with small cyia and like the Bell animals its mouth is encircled by large cyia in stentor the cyia around the mouth are fused in groups called membran Els actual grains of pigment in the body will give color to the various species of stentors brown green or blue a stentor looks like a deep sea monster as it streamlines its shape for swimming notice how the strong membran elves are used as propellers as it swims off in its structure and adaptability stentor is one of the most complex single- celled animals but single celled plants and animals are not all the forms that we might find in our drop of pond water some are composed of many cells and are quite specialized one of these is Hydra whose sacklike body of two layers of cells makes it a relative of the jelly fishes and corals Hydra is a meat eater lurking like an octopus without spread tentacles until some small animal brushes against them then the Hydra paralyzes the prey with a shower of poisonous threads the animal is then seized by the hydra's tentacles and transferred to its mouth hydras May reproduce sexually by developing specialized cells which form eggs or sperms usually they reproduce by budding this process like fion requires only one parent either a male or a female Hydra can grow a bud which shares the nourishment of the parent body nerve cells in both parent and Bud coordinate their muscular reaction until the bud breaks off the Swift little animal feeding around the Volvo's colony is a rotifer another many celled form of microscopic life the free swimming rotifers sometimes attach themselves temporarily to a feeding spot and some species of rotifer remain permanently attached to a plant or stone or tiny object rotifers have a two blike digestive system with a mouth and anus for oneway traffic of food for chewing aifer has a strongly muscled food chopper called a master in its throat the circle of cyia crowning the head sweep bits of food into the mastex other species of rifer are even more specialized this type builds itself a protective tube by cementing together tiny bits of debris while this species lives in colonies the Beautiful loes with their moving cyia seem to revolve giving us the name rifer which means wheel Bearer these living forms are much more complex than the simple amoeba but all of them must meet the basic requirements of Life moving reacting obtaining food and reproducing these are the same requirements needed by higher forms of life even our own requirements for living are no different than those we see in the teeming life in a drop of water [Music]