Biology Lesson Notes Characteristics of Living Things By the end of this topic you should be able to: identify the vital functions characteristic of all living things recognize the cell as the basic unit of any living organism comprehend the common features of all cells as well as the basic differences between animal and plant cells analyze the relation between the structure and function of specialized cells understand that cells, tissues, organs and systems represent increasing degree of organization in living organisms Form 3/SS+NS/ss/12-13 Characteristics of Living Things Biology Lesson Notes The Seven Vital Functions Living things include microbes, plants and animals. They live on the land and in the lakes, rivers, and seas. All very different but all are alive. All can perform some common features These are the Seven Vital Functions. Only living things have all of these features They are “tests” of being alive. The Vital Functions are processes that all living organisms do. They tell you whether something is alive or not. Form 3/SS+NS/ss/12-13 Characteristics of Living Things Biology Lesson Notes Movement Living things move without outside help. Non-living things move under external forces (e.g. machines, something falling). Organisms like animals can move their whole body (E.g. walking, running, etc.) Organisms like plants can only move parts of their body (E.g. opening and closing of flower petals) Form 3/SS+NS/ss/12-13 Characteristics of Living Things Biology Lesson Notes Can you match these types of movement to the pictures? Flying Chasing for food Form 3/SS+NS/ss/12-13 Venus fly-trap catching insects Migration Swimming Turning flower towards sun Characteristics of Living Things Biology Lesson Notes Sensitivity (Irritability) Living things respond to conditions around them. Organisms can identify stimuli in their surroundings and respond to them. Stimulus Green plants growing toward sunshine Form 3/SS+NS/ss/12-13 Organism Blinking when light shines into their eyes Response Jumping up when stepping on a sharp pointed object like a pin Characteristics of Living Things Biology Lesson Notes Can you match these responses to their stimuli? Gravitational pull Roots grow into soil Roots grow down Insect touches hairs on leaves The Venus fly-trap catches insects Insect trapped Sun sets Flowers close during the night Flower closed Smell of predator A deer runs away from a lioness Fast running Form 3/SS+NS/ss/12-13 Characteristics of Living Things Biology Lesson Notes Nutrition (Feeding) All living things try to get food, and they get it in different ways Bite with teeth (e.g. Humans and other Animals) Suck up food with specialized suckers (e.g. flies and other insects) Absorb it (soak it up) through membranes/skins (e.g. Bacteria and Fungi) Do you know of any other ways of feeding? Amoeba engulfing food Form 3/SS+NS/ss/12-13 Swallowing prey whole Characteristics of Living Things Biology Lesson Notes Some organisms can make their own food from water, CO2, nitrogen, and minerals. Green plants Photosynthesis is the build-up of food from Carbon dioxide and water using the Sun’s light energy. Carbon Dioxide Water 6CO2 6H2O Chlorophyll Light Enzymes Glucose Oxygen C6H12O6 6O2 The Equation for Photosynthesis Form 3/SS+NS/ss/12-13 Characteristics of Living Things Biology Lesson Notes Respiration (Energy) All living organisms need energy. They get this energy by burning food, using a chemical process known as Respiration Aerobic respiration uses oxygen to release energy from food. Anaerobic respiration does not use oxygen to release energy from food. Respiration is the burning of food (glucose) to produce energy. Glucose Oxygen C6H12O6 6O2 Enzymes Carbon Dioxide Water Energy 6CO2 6H2O 2830kJ The Equation for Aerobic Respiration Form 3/SS+NS/ss/12-13 Characteristics of Living Things Biology Lesson Notes The oxygen needed for aerobic respiration comes from the environment Humans get oxygen by breathing in air Fish get oxygen from water Aerobic respiration produces carbon dioxide, which is removed when we breathe out. This exchange of gases is called gaseous exchange There are different organs for this: E.g. lungs in mammals, gills in fish, leaves in plants. Form 3/SS+NS/ss/12-13 Characteristics of Living Things Biology Lesson Notes Growth Non-living things become larger. E.g. Balloon grows, salt crystals grow in salty water as it evaporates Living organisms turn some of the food into living material (bones, teeth, wood, etc.). Repairing body parts (healing injuries, replacing worn parts): E.g. Shrubs and trees cover injuries with bark; Crabs grow new legs when old ones are lost; Human beings heal cut skin and broken bones. Becoming bigger: e.g. chick hen; Child Adult Becoming more complex: e.g. Caterpillar Butterfly Living things grow by Making new parts: e.g. teeth in children. Form 3/SS+NS/ss/12-13 Changing old parts: e.g. grasshopper sheds “skin” to make new one. Characteristics of Living Things Biology Lesson Notes Excretion A lot of chemical reactions take place in the body. Chemicals are broken down to produce energy (respiration). Chemicals are built up to form new body structures (growth). These reactions are called Metabolism. Waste materials are produced These would cause illness and death if not removed. Excretion is the process of getting rid of these waste materials. For e.g. in animals, ammonia, which is very poisonous, is removed by first turning it to a less harmful substance and then passed out of the body as a liquid called urine. Excretion is the removal (from the body) of waste products resulting from metabolism. Form 3/SS+NS/ss/12-13 Characteristics of Living Things Biology Lesson Notes Two other processes also result in the removal of substances from the body Egestion the removal of undigested food from the body Since this food has not taken part in any chemical reaction, it is not considered as part of excretion. Secretion the release of useful substances produced by cells or glands into or out of the body. E.g. tears are secreted under the eyelid. Tears are not a harmful substance, and not a waste product. Can you think of other ways in which we get rid of waste materials? Sweating (heat and urea) Form 3/SS+NS/ss/12-13 Exhaling (CO2 and water) Excess Water (urine) Characteristics of Living Things Biology Lesson Notes Reproduction All living organisms eventually die. They avoid becoming extinct by producing copies of themselves. Offspring have the same characteristics as parents. Reproduction is the production of new individuals of the same species (kind of organism) Form 3/SS+NS/ss/12-13 Characteristics of Living Things Biology Lesson Notes Asexual reproduction Simple microbes (bacteria) reproduce by dividing into two sections. Each section becomes a new living organism. Sexual reproduction Other organisms (most animals) produce new individuals by combining characteristics of two parents. Some organisms (e.g. insects) have more than one form in their life-cycle E.g larva and adult. Can you mention what different forms these organisms have in their life-cycles? Frogs have tadpoles Form 3/SS+NS/ss/12-13 Dragonfly larvae spend about 3 years in an aquatic environment Butterflies have caterpillars Characteristics of Living Things Biology Lesson Notes Worksheet Description of Process / Activity Vital Function Escaping from danger Making new leaves Sweating Having a snack A plant makes and releases seeds Oak trees develop from acorns Laying eggs Movement Respiration MRS Form 3/SS+NS/ss/12-13 Sensitivity Nutrition Excretion Reproduction Growth NERG Characteristics of Living Things Biology Lesson Notes Description of Process / Activity Vital Function Hearing a whistle Using up energy in a race Changing position or posture Releasing energy from food Getting rid of excess water as urine A lion tearing and biting the flesh of a zebra it has caught The breakdown of food to release energy The change of a larva (caterpillar) into a butterfly Movement Respiration MRS Form 3/SS+NS/ss/12-13 Sensitivity Nutrition Excretion Reproduction Growth NERG Characteristics of Living Things Biology Lesson Notes Summary All living things do the following things: Respire: they break down food to obtain energy. Most organisms need oxygen for this. Feed: food is needed for energy and for making new cells. Plants make their own food by photosynthesis but animals, fungi and most bacteria must obtain it from other living organisms. Excrete: respiration and other chemical processes in cells produce waste products which have to be expelled. Reproduce: all organisms eventually die. Species persist only as result of reproduction. Reproduction may be sexual or asexual. Grow: the cells of an organism increase in number and size. The cells also become specialized and the organism increases in complexity. Move: most organisms move, or make movements at some stage in their lives. Respond to stimuli: living organisms are sensitive to their surroundings and respond to changes in their external and internal environment. Form 3/SS+NS/ss/12-13 Characteristics of Living Things