Introduction To Biology (1952)

[Music] in biology we study life in all of its forms today surroundings may include variety of living things by applying biological principles many of us are able to control different living things for our own good and for the benefit of others thus farmers learn to improve crops and animals to provide us with food doctors learn how vaccination helps to control germs the tiny plants and animals that cause disease breed horses learn to improve their animals for such specialized uses as racing sanitary workers learn to control pests by spraying their breeding places of whatever the kind of control involved it depends upon applying principles of biology for biology is the study of all living things biologists learn how plants and animals live what they eat how they reproduce how they protect themselves biology is divided into two vast kingdoms the kingdom of plants botany and the kingdom of animals zoology most biologists are specialists that is a zoologist may study one type of animal such as insects the specialty called entomology or reptiles especially called herpetology or birds the specialty called ornithology a botanist may specialize on one type of plant life still other biologists concentrate on problems that affect both animals and plants such as the processes taking place in living things so there is a variety of specialties that make up the general field of biology this means that biology offers many opportunities for interesting and profitable work but just how-- as biology applied to a specific problem such as a problem of disease here's an example a few days ago this rabbit was purposely infected with a disease now the rabbit has recovered the problem is to discover whether a serum made out of this rabbits blood will protect humans from the same disease after a period of extensive research laboratories begin collecting the serum and large quantities the serum is packaged as individual doses it's the product of biologists applying their different skills to benefit humanity here is another example of biology at work the problem this time is how to control mosquitoes one of man's worst test since there are so many mosquitoes killing them one by one is obviously impossible some other kind of control is needed mosquitoes lay eggs and stagnant waters so one way to control them is to drain away stagnant waters and clean up swamps but a complete cleanup of this sort is often impossible so different means must be considered entomologist know of course that mosquito larvae the immature young mosquitoes develop into adults while remaining submerged in stagnant water the larvae breathe air from above the surface of the water through small cubicles if the air supply is cut off the larvae die of suffocation one way to cut off the air is to coat the surface of the stagnant water with oil but first the right kind of oil coating has to be developed then sanitation workers can apply the chemicals where mosquitoes are breeding biology is an extensive subject so it is fortunate for those who study biology but there are some basic biological principles applicable to many kinds of life to begin with every living thing is made up of one armed ourselves lien hawk a pioneer in a development at a microscope in the 17th century was the first to observe Manute plants and animals made up of single cells except for bacteria and certain algae which are one cell plants all others are made out of many cells grouped together some plants can live only if they feed on other organic things each of these is either a parasite that lives on other living plants or animals or a saprophyte that lives on other dead plants or animals this simplified is growing on a decaying banana peel in contrast there are many green plants and all of these can manufacture their own food supplies as in the kingdom of plants there are also countless kinds of life in the animal kingdom some of the simplest of all animals are like this amoeba there is just one cell in this animals entire body sponges are loosely organized colonies of single cells then there are animals of a jellyfish family that have more complicated structures there are worms of many kind a large family of water-loving animals called mollusk such as this octopus thousands upon thousands of kinds of insects and finally the animals with backbones the vertebrates fish belong to this rule so do reptiles birds and mammals mammals are the warm-blooded animals that nourish their young with milk man is a mammal but unlike any other mammal man walks naturally in an upright position this characteristic is made possible by his skeleton besides the advantage of upright position man has a superior brain that makes him the master in many respects of every other kind of living thing like other living things however man has fundamental needs such as the need for food men and other animals cannot make their own food instead they rely upon green plants either directly or indirectly for their food green plants manufacture foods by several processes but the most important one is called photosynthesis carbon dioxide gas enters the leaves from the air and water reaches the leaves through the roots from the soil these materials come together in the green cells of the plant rays of the Sun and chlorophyll a green substance inside the plant change the water and carbon dioxide into sugars this process is photosynthesis green plants usually make more food than they can use this surplus and the cells of the plants themselves provide the ultimate source of food for all animals and for most non green plants some animals live indirectly on green plants that is they prey upon other animals that have fed directly on plants getting food is only one essential of the problem of living protection against the weather and hungry animals is another essential protection may mean older protection may mean keen ears and strong legs protection may mean a stinger plants too often have structures which may protect them like thorns or nettles or thick bark most animals and plants are well adapted to the living conditions in their own native surroundings they are suited to the temperature the food supply and the other things in that environment the study of these relationships is called ecology many living things have cells tissues or organs which do special jobs for example in man breathing is a job involving the lungs oxygen is carried by the blood to all cells of the body circulation of the blood through the body takes a kind of pump called the heart here are valves of the heart at work in the cells oxygen from the air combines with food and releases energy the energy which the cells require in order to live this burning or oxidation of food in the cells is called respiration carbon dioxide a waste that forms as the food burns is carried by the blood back to the lungs and exhaled besides such vital processes there are others like hearing that even though less essential make our lives more meaningful for example study of the human ear reveals its appearance from inside the skull at the left is the eardrum attached to it are bones that transmit the sounds which ultimately reach the brain knowing such facts helps us understand the functioning of the ear the eye is another the sense organs that helps us understand and appreciate our surrounding besides living from day to day every form of life must either reproduce its kind or die out most microscopic forms of plants and animals have a very simple way of reproducing they just divide into two parts like this amoeba is doing then each part lives on as a new animal even in many multicellular organisms especially plants a new organism may develop from a part of another another kind of reproduction requires two parents in this plant for example grains of pollen come from the male part of the plant the pollen germinates and grows into the female part of the plant where the egg is located a male sperm from pollen grain fertilizes the egg which becomes the first cell of a new plant inside the sea this is a kind of sexual reproduction in some plants and most animals sexual reproduction requires two completely separate parents in an animal for example the pig eggs form in a part of the female's body called the ovary if a sperm cell from a male parent reaches a mature egg under the proper conditions threatened ization takes place then the fertilized egg or zygote begins to divide and a new organism or embryo starts to grow embryology is the study of the development of embryos since Gregor Mendel discovered the basic principles covering the transmission of hereditary characteristics from one generation to the next biologists have made tremendous progress in improving animals by carefully selecting breeding stock and offspring they have improved different kinds of plants and animals in order to increase meat and egg production to obtain finer wool to produce crops which yield more bushels of seed to the acre and turbo qualities in living thing so we've explored some crop each problem each process each living thing offers further proof that studying biology means studying life itself through such study we learned to understand ourselves more fully and also become better acquainted with the fascinating life that is part of our environment [Music]