The study of the life cycle involves all those sciences that study life. Life can be defined in terms of the smallest submicroscopic particles to the largest and most imposing of plants and animals. The life cycle is the accumulated knowledge about all living things and the principles and laws that govern life from birth until death.
Those who specialize in biology are known as biologists or, in a general sense, naturalists. It is through their observations of nature and natural phenomena that the great ideas of biology are born. Subfields of biology include botany, zoology, physiology, entomology, and many other specialized fields.
The scientific inquiry into life had to develop early on in human existence. Certainly early people like the Chinese, Arabs, and Africans didn't record their findings nor attribute them to any one person. These people were merely interested in the establishment of growing crops, using animals for food and clothing, and learning that cloth and color can be derived from plants. This marks the early beginnings of understanding and learning about life. A great deal of credit is due to the Greeks for having recorded a systematic study of living things. Hippocrates (460-370 BC) founded the first medical school on the Greek Island of Cos. Aristotle (384-322 BC) founded the systematized study of natural history. Theophrastus (380-287 BC) founded botany. Galen, a Roman (130-200 BC), founded the science of anatomy. Andreas Vesalius, Marcello Malphigi, Robert Hooke, William Harvey, Anton von Leeuwenhoek, Carolus Linaeus, George Cuvier, Jean Baptiste Lamarck, and Charles Darwin are just a few names that mark the historical development of biology.
The subject of life is indeed complicated. Explaining how cells duplicate to make organisms or how these organisms live together in an interactive ecosystem is not easy. There are, however, many underlying themes within the life cycle including homeostasis, unity, adaptation, and evolution.
Homeostasis is the maintenance of a stable internal environment be it in a cell or an organism as a whole. This is a necessary condition for life and must be maintained throughout the entire life cycle. The internal chemical balance of the cell must be maintained at a steady state to promote the innumerable biochemical activities that fasten the production or use of energy. The human body constantly adjusts to changes in order to maintain biological equilibrium.
Unity is shared by all living species in that they have certain biological, chemical, and physiological characteristics in common. All organisms adapt to their specific environments in order to survive. Organisms must somehow live in harmony with other organisms, and the physical limitations that might be set by the surrounding environment. These physical limits can include climate, wind conditions, rocks, or water.
Adaptation is the flexibility of life to "cope" with its surroundings. All organisms must adapt to their environments, if not, they either move to another environment that is suitable or they die. Adaptation involves changes that an organism makes in order to better survive in its environment. Typically, adaptations occur over time so that each successive generation is better suited to survive.
Evolution, or the ability of organisms to change with time, is a process that selects genetic traits which are advantageous for the survival of a species. Evolution is irreversible, but it is always trying to improve the species in order for it to adapt better to its environment. When environments change organisms must be able to evolve with them. Environmental stability over extended periods of time is something most organisms don't enjoy. Natural disasters such as fire, famine, and drought often influence changes in organisms. The organisms in turn must be able to adapt in a way to cope with long term changes through natural selection.
Is life unique? On planet Earth, life is a persistent occurrence, but compared to other planets, life is a unique form. To determine if something is living one must look for signs of movement, response to touch, patterns of growth or the ability to take in or make food. But for every definition that might be formulated for life, there are many exceptions. Living things grow, but mineral crystals can be made to grow also. Living things move, but so does a ball rolling down a hill. Life is best described in terms of the integration of life sustaining functions. A living organism must carry on specific biochemical and biophysical activities continuously in order to maintain life defining processes.
Scientists who deal with living organisms are faced with very difficult parameters. They try to model or make sense of what living cells are capable of doing. They mathematically develop modeling tools; they engineer highly technological microscopes to see organisms; they spend millions of dollars in biological and medical research; but still don't know how life evolves and how life functions. The rules for life sometimes change without notice. Life is truly a miracle.
Elementary age students need to learn about different animals, their bodies, plants, and how organisms live with one another. There are many different components to the life cycle, but the above mentioned themes penetrate the understanding of the content material. The Integrating Science, Math, and Technology (I. Science MaTe) Curriculum divides the LIFE CYCLE into the content themes of Organisms, Human Body, Plants, and Natural Environment. Each of the themes pull together the major ideas and apply them to specific groups of organisms.
ORGANISMS - examines the diversity of living things on Earth. Students need to understand that there are different groupings of organisms, both natural and artificial. Students learn to understand how organisms are classified and their significance in the current six kingdom classification system. Students learn that there are many organisms with unique lifestyles and environments. Key concepts that are learned include comparing small and large organisms, organisms with different requirements for life, cells, tissues and organs, reproduction by either asexual or sexual means, and that there is more to classification than just plants and animals.
HUMAN BIOLOGY captures the major principles learned in ORGANISMS and applies them specifically to humans. Humans are highly developed organisms with various organ systems that are adapted for performing life sustaining functions. Each organ system works with other organ systems in the total activity of the body. As humans, we learn about our bodies, and the needs and the things that make for successful living. The human body is very difficult to understand. Students learn about the different parts of their bodies by looking at hands-on models. They compare and contrast the different models with their own bodies. Students will examine in detail their 5 senses, as well as their circulatory and skeletal systems. Comparing and charting human growth will allow students to investigate their own body growth patterns. Students will learn the function of organs as well as how the organs form systems and how these systems interact.
PLANTS surround and influence our very existence through their ability to supply oxygen to the atmosphere. Thus, the factors that influence plants also greatly affect the animal world. Children see plants all around them so they are familiar with their uses. Teachers can use this general knowledge to extend the students' understanding of plants. Throughout the activities there are many illustrations of how plants are used for shelter, wood, clothes, paper, food, and drugs. There are two ways to produce useable items in this world, either by growing or by mining. Photosynthesis, classification, and reproduction are investigated throughout the unit.
NATURAL ENVIRONMENT looks at the harmony that exists in nature. Students learn the delicate and complex biological, physical, and chemical systems of our world which we share with all living and non-living things. The goal of this unit is to make children aware of the intricate balance that exists between all levels of life and more importantly, how any break or change in a "link" will affect the "chain" as a whole, including the human species. Students will learn about the requirements of the different ecosystems by looking at the individual, population, community, and ecology. They will compare and contrast different biomes throughout the world, as well as understand the food chain and web.
The life cycle also includes death, but in dying, organisms leave enriching organic matter that makes the soil rich in chemical nutrients. Growth begins where death occurs. Reproduction is also another life strategy that allows organisms to continue. However, extinction is also part of the life cycle, whereby organisms whose numbers get down to a critically low level, cannot sustain their species. But the evolution of organisms has helped life to continue on the planet, because the mechanisms of evolution help organisms adapt to a changing world. Through time and changing environment on this Earth, life is held in a delicate balance.
Children are fascinated with living organisms and enjoy learning about different forms of life. Children may know what certain organisms look like, but may not understand the natural habitats of these animals because many organisms have such unique lifestyles. These activities can easily be made "hands on" by bringing in an entire zoo of organisms, but there are alternative ways of allowing students to observe living things. The key concept for this unit includes learning that there are other organisms besides humans, dogs, and cats. These organisms all reproduce to insure that their respective species will survive. Students should appreciate that we as humans are only a small constituent of our living planet. Many of the biological concepts are reinforced every year.
I. LOWER PRIMARY - DISTINGUISHING DIFFERENT TYPES OF ANIMALS
Students learn the meaning of classification and how information about different organisms can be derived. The students will compare large and small organisms and recognize the requirements of non-living and living things. Also, they will begin examining the characteristics of vertebrates and comparing these characteristics with those of invertebrates. Students will begin a preliminary examination into the habitats of both aquatic and land animals.
II. UPPER PRIMARY - LIVING REQUIREMENTS AND CLASSIFICATION
By comparing and contrasting cells, tissues, and organs, the students will understand how different organisms have different requirements. Students will learn that classification and taxonomy help to understand organisms and will gain an appreciation for vast knowledge that is derived from these two modes of scientific study. Students will take a close look at invertebrates, fungi, protozoa and will investigate animal and plant cells and compare and contrast how different organisms reproduce.
The human body is a living, thinking machine that carries on countless functions every minute of every day. Humans can walk, talk, and eat with ease and yet we seldom stop to think how this is possible. In the lower primary grades children should learn the basic internal and external body parts and their functions. In the upper primary grades children should be taught that the body systems work together to provide all necessary processes required for life. With this knowledge, children can better understand why they should acquire good eating habits, good oral hygiene, and regular exercise in order to keep their bodies in the best possible condition.
I. LOWER PRIMARY - HUMAN DESIGN
The human body is very difficult to understand. Children cannot see inside of their bodies so they have to learn to interpret the exterior signs. By comparing and contrasting different models with their own bodies, students will learn the various body parts. Students will examine in detail their 5 senses, as well as study the circulatory and skeletal systems. By comparing and charting human growth the students will investigate their own growth patterns. Students will also learn the functions of individual organs.
II. UPPER PRIMARY - ANALYZING HOW BODY SYSTEMS WORK
Understanding the human body is important for the growing child in the upper primary grades. Anatomical knowledge will prevent misconceptions about the male and female bodies. Students will look at the body systems in more detail. They will begin comparing and contrasting the differences between the sexes. They will begin to understand why proper diets are important for their growing bodies. They will investigate different illnesses caused by bacteria, viruses, and genetic inaccuracies. The unit will be concluded with an investigation into the changing hormone system which prepares the young human body for its adult life.
We are not only surrounded by plants but are totally dependent upon them for the oxygen and food they produce. Therefore, the factors that influence plants also greatly affect the animal world. Children see plants all around them so they are familiar with the uses of plants. Teachers can use this general knowledge to extend the students' understanding of plants. Throughout the unit there are many illustrations of how plants are used for shelter, wood, clothes, paper, food, and drugs. There are two ways to produce useable items in this world, by growing or mining, and plants do the growing. Photosynthesis, classification, and reproduction are investigated throughout this unit.
I. LOWER PRIMARY - PLANT PARTS
Students begin to develop a basic understanding of the functions of different plant parts. They will learn the different requirements that plants need in order to grow. They will investigate how the cells and tissues of plants compare to those of other organisms. The students will be introduced to photosynthesis. Students will also investigate different plant parts and will learn how to differentiate species of plants while learning the function of plants in society.
II. UPPER PRIMARY - PHOTOSYNTHESIS AND REPRODUCTION
Students will learn about vascular and nonvascular plants and their functions in the environment. They will look closely at the differences between angiosperms and gymnosperms, by comparing leaf and seed structure, as well as function. Students will investigate photosynthesis by studying different components of the plants. Students will compare plant organs and tissues with plant systems. Reproductive modes displayed by plants will be analyzed.
In order for people to live in harmony with nature, we must understand the delicate and complex biological, physical, and chemical systems that exist in the world we share with all living and non-living things. The goal of this unit is to make children aware of the intricate balance that exists between all levels of life and more importantly, how any break or change of a "link" will affect the "chain" as a whole, including the human species. Students will learn about the requirements of the different ecosystems by looking at the individual, population, community, and ecology. They will compare and contrast different biomes throughout the world, and will understand the food chain and food web by looking at world, national, and local examples.
I. LOWER PRIMARY - REQUIREMENTS FOR LIFE
Students will examine land and marine environments by comparing and contrasting the communities that inhabit these areas. They will look at how producers and consumers are classified in a simple food chain. They will investigate the different requirements that each of the biomes of the world offer as well as requirements of individual organisms in the ecosystem. They will explore the differences between a food chain and a food web in land and in marine environments.
II. UPPER PRIMARY - ECOSYSTEMS
Students will look at specific ecosystems and evaluate their physical and biological components. They will explore ecosystems including those of a salt marsh, soil, and fresh water aquarium. They learn about different corals throughout the world's oceans. Students will conduct a population study by looking at specific land organisms. Students will probe and try to understand how the environment uses natural selection to alter the biological community that lives in a physical environment. Examples of adaptation, extinction, and evolution are investigated.
[Back to Life Cycle Grid]