What Is Ecology? (2nd Ed, 1977)

is the Deep Green Forest is a vast complex Web of Life by observing the plants and animals of the forest we can learn about ecology ecology is the study of the relationships among plants and animals and the environment in which they live [Music] our study of ecology will include several biomes the forest the harsh dyed desert the shoreline where Land and Sea meet and the city land dominated by man biomes are the great communities of living things that occupy major portions of the Earth the deciduous forest biome is dominated by trees that usually shed their leaves in autumn in every biome food chains Exist by studying these food chains we can determine the pathways by which energy flows through the biome food chains begin with sunlight when green plants change the solar energy to chemical energy these plants produce food from carbon dioxide and water by a process called photosynthesis thus green plants are called producers because they provide food for all other organisms in the biome at the next level of the food chain we find primary consumers animals which directly utilize the food energy produced by plants in the deciduous forest biome deer are one example of a primary consumer consumers that eat only plants are called herbivores insects are among the most numerous primary consumers they may be found by the hundreds of millions in any Forest these primary consumers are prayed upon by animals of at the next level of the food chain carnivores or meat eating animals toads and other carnivores are secondary consumers consumers at the next highest level of the food chain animals which hunt and kill other animals for food are called Predators the Predator prey relationship is one of the most common interactions between animals the food chain doesn't stop here there are other carnivores at higher levels this relationship between predator and prey between animals higher in the food chain eating animals at lower levels is a fundamental relationship among living creatures in any biome the hawk is at the top of this food chain no animals prey on it a food chain may be drawn as a pyramid energy flows from the base to the top of the pyramid at each level some energy is lost and there are progress aggressively fewer individuals dead material is broken down by decomposers usually bacteria and fungi in this way organic matter is returned to the Earth scavengers are animals which feed on dead animals which they themselves have not killed among scavengers there may be competition for food scavengers form a special link in the biome in any given biome many food chains may exist food chains such as this are common to most biomes on Earth this Pond is a separate environment or habitat within the deciduous forest biome as in other habitats of the forest the creatures living here have complex inter relationships many of these animals are in the pond habitat only part-time they spend most of their lives in other parts of the forest the pond is part of the forest biome and is strongly influenced by the forest for instance the thickness of the overhead tree canopy determines how much sunlight reaches the pond and thus affects plant and animal life found here in the pond habitat there are also producers and consumers that form a food chain small plants may be eaten by animals that live in or near the pond however at the base of the Pond's food pyramid are the microscopic producers called phytoplankton in the pond water algae multiply rapidly taking their energy from sunlight falling on the pond algae are very simple microscopic IC green plants decomposers are found in the pond too bacteria which feed on dead material algae and bacteria are in turn eaten by protozoa simple microscopic animals that live in water habitats some protozoa are primary consumers others are predators here an amiba consumes a parami fish Prey Upon organisms which have eaten the protozoa thus adding another link to the food chain parasites May feed on the fish a parasite is an organism that feeds in or upon another organism which is called the host the host is generally injured by the parasite and may in time die die from the injury this Pond will not always be here dead material will accumulate on the bottom and as more plants grow their Roots will hold sediments washed from the surrounding Forest the pond gets smaller and someday will be dry land like the rest of the forest biome this process is called succession succession can be seen very clearly at a beach at the water's edge the beach is Sandy and exposed to wave action no plant life grows here farther Inland conditions are less severe and decaying material adds organic matter to the sand here plants begin to grow and anchor the sand dunes Beach grasses and various kinds of shrubs organic matter from dead plants turns the sand into Rich humus the small trees such as willows and cottonwoods appear finally a forest begins to grow as Oaks and hickories take hold succession is change change from one kind of plant and animal community to another [Music] the desert is another type of biome it's a harsh environment but a complex Web of Life exists here too moisture comes to this arid biome only from a few winter snows occasional rain showers and Dew sometimes precipitation comes too fast and hard the dry Earth can't absorb it all and flash floods race across the land eroding the soil and tearing up plant life but the moisture brings life too cacti flour and produce fruit which becomes food for desert animals desert plants show adaptations for survival in this dry environment cactus plants have long root systems close to the ground surface in order to soak up as much moisture as possible they have spines instead of leaves reducing moisture loss and providing protection okao plants grow leaves only after it rains or snows when dry conditions return these leaves will drop off so the plant conserves moisture animals obtain their water from the plants they eat or from Dew In the Heat of the day most animals rest in the shade only a few are active hunting for food the Setting Sun brings cooler temperatures daytime animals withdraw to rest and other animals begin to stir nighttime animals begin to feed where only a few hours before daytime animals were active in another biome the rocky Shore lack of moisture is certainly not a problem the ecological relationships of this biome are governed by water action waves constantly pounding against the rocks and Tides washing over the shore Every Day Life is rugged for the animals living here however shore birds find the environment to their liking there are plenty of marine animals to feed on on the rocky Shore there may be fierce competition for space best places to eat sleep mate and raise young in any ecosystem living things constantly absorb transfer and circulate energy here too there is a cycle of life and death with dead plants and animals returning materials to the environment by observing interactions among living things ecologists can gauge a biomes Health we can think of the earth as one huge biome or ecosystem which can be divided into spheres the lithosphere or crust the hydrosphere or water and the atmosphere or air the biosphere takes in all three it is the thin fragile Zone where all life exists on Earth the activities of human beings have a tremendous impact on the biosphere many of these activities are damaging we have built giant crowded cities which have obliterated entire communities of Life great islands of concrete steel and glass have replaced soil green plants and animals we can think of cities and their suburbs as a kind of biome an urban ecosystem where relationships are determined by the changes human beings have made in the environment certain kinds of animal most thrive in the urban ecosystem simply because they are scavengers able to feed on the waste products of our cities an urban ecosystem generates enormous amounts of waste which is a food supply for large numbers of scavengers producers green plants are largely absent from an urban ecosystem where concrete has replaced soil even so the natural world has not been forgotten on this wall artists have painted pictures of endangered animal species animals whose continued existence is threatened by human activities the message is clear we can't continue to destroy life in the biosphere some people try to bring a part of the natural world into this Urban ecosystem a rooftop garden brings green plants back into the man-made biome of the city the primary producers for the urban ecosystem are found outside the city in agricultural ecosystems like the urban ecosystem Farms are man-made and man Alters the relationship among animals plants and soil for his own needs instead of a great variety of green plant producers Farms have a very limited number of plant species which are used as food by humans and their domestic animals the agricultural ecosystems can't exist without careful attention from humans and in such a simplified ecosystem huge inputs of dangerous chemicals are necessary new methods of controlling pests are now being introduced apples are one of the most important fruit crops in the United States but large numbers of insects attack apples so vast quantities of pesticides are used on them ecologists believe it's possible to control some of these harmful insects by introducing beneficial insects that will prey on them one of these insect pests is the larvae of the Colin moth which lives in and spoils apples a species of wasp from Afghanistan is a predator of the Colin moth attempts are being made to establish the wasp in California and in other parts of the world where apples are grown the WASP doesn't prey directly upon the Colin moth instead the female lays eggs in the Cocoon where the larvae of the moth is dormant when the egg hatches the WASP larvae feeds on the larvae of the Colin moth thus killing it as in a natural ecosystem the parasite controls the population of the host this wasp is laying her eggs in specially built nests containing Colin moth cocoons in the the pupil or resting stage the Wasps are gathered and attached to sheets of paper each piece of paper contains several thousand wasp Pupi the WASP Pupi are shipped to Orchards all over the world world this is an example of biological control applying the knowledge we gain from ecology applied ecology depends entirely on our knowledge of living things and the environment these students are studying Canada Goose populations the Ecology of a biome the communities within it and the ways animals interact must be studied in the field because ecosystems are Dynamic alive they can't be dismantled and taken into the laboratory each goose is banded with a tag and the date and location are recorded if the tag is later recovered scientists May learn something about the bird's feeding habits movements and even the kinds of problems it Encounters in the environment we need knowledge like this for many reasons not just to help the geese survive but more importantly to learn what must be done so that we may survive that's the essence of ecology keeping the ecosystem we call the Earth alive and well a