Master Curriculum Topic Study: Human Body Systems

Transcription

1 Master Curriculum Topic Study: Human Body Systems Session C Section I: Culminating Ideas for Adult Literacy 1. The fundamental building block of organisms is cells. a. Cells combine to form tissues, which compose organs that perform specific functions. b. Several organs form an organ system. Important organ systems include: i. Circulatory ii. Digestive iii. Endocrine 2. Humans evolved over time from other organisms. 3. Humans reproduce sexually. A sperm cell from the male combines with an egg cell from a female to form a fertilized egg cell. The cell divides into two identical cells. Over time, the cells form organs. After 9 months, an infant is born. a. The health of the infant is determined by genetic factors and the health of the mother. b. An infant born prematurely may not be able to live outside of the womb. 4. There are several important developmental milestones. a. Puberty is the age at which a human becomes able to reproduce. b. Menopause is the age at which a woman no longer produces eggs. 5. Organisms can be classified. a. Five kingdoms: animal, plant, fungi, Protista, monera b. Further divisions include phylum, class, order, family, and genus Section III: Concepts and Specific Ideas Italicized statements are from the National Science Education Standards, while non-italicized statements are from Benchmarks for Science Literacy. Grade Human Identity People have different external features but are more similar to each other than other animals. People have the same basic needs as other animals: water, food, air, waste removal, etc. Plants require air, water, nutrients and light. Organisms can only survive in environments where needs are met. People live in communities in which individuals have different roles. 3-5 Behavior in many non-human species is almost completely decided by biological inheritance. Technology extends human skills beyond what biology provides us. Preserved remains indicate that humans lived long ago and offer insight into their behaviors. Organisms change the environment that they live in. Humans change environments in ways that can be beneficial or detrimental for themselves and other organisms. 6 8 Human beings have body systems for obtaining and providing energy, reproduction, etc. The internal similarities of humans make blood and organ donation possible despite social and cultural differences. Fossil evidence is consistent with the theory that humans evolved from earlier species. Technology offers humans advantages over other organisms. Technology has also affected the way humans live (i.e., sanitation, disease prevention) Human similarity extends to genetics, anatomy, and cell chemistry. Written records facilitate the sharing and usage of information.

2 Grade Human Development All animals have offspring, usually with two parents. People may prevent some animals from producing offspring. A human baby grows inside its mother until birth; after birth, its survival relies on adults. 3-5 It takes about 9 months for a human embryo to develop; the development of the embryo depends on the substances the mother takes in. Humans live longer than most animals, but all living things die. There are common developmental stages in humans though individuals may reach them at different times. Plants and animals have life cycles that include being born, becoming adults, reproducing, and dying. This cycle varies between types of organisms. People are usually biologically capable of having children before they are able to care for them. Plants and animals closely resemble their parents. Some characteristics of organisms are learned (ex. riding a bike) and can t be passed on to future generations, while others are inherited (ex. hair color). 6 8 Fertilization occurs when sperm cells from a male s testes are deposited near an egg cell from a female ovary. Most of the time, by chance or design, sperm never arrives or egg isn t available. Contraceptives may incapacitate sperm, block the way to the egg, prevent the release of eggs, or prevent the fertilized egg from implanting in the uterine wall. A mother s malnutrition and drug, alcohol, or cigarette use risks the well-being of the child. As adults age, muscles and joints become less flexible, energy levels lessen, and senses become less acute. Women stop releasing eggs and can t reproduce. Quality of life is influenced by sanitation, diet, medical care, gender, and personal health behaviors As successive generations of an embryo s cells form by division, small differences in their environment cause them to develop differently, by activating or inactivating parts of DNA. Using artificial means to prevent or promote pregnancy raises political and ethical questions. The longevity of human development is associated with the prominent role of the brain in human evolution. Humans are able to learn throughout their lives. The development of technologies to maintain, prolong, or terminate life raises legal, social, and ethical issues. Grade Basic Functions The human body has parts that help it find and take in food when it feels hungry. Senses can warn people about danger and help them get out of it. The brain allows people to think and sends messages to other parts of their body. All animals depend on plants, as a food source or as the food source for their prey. 3-5 People obtain energy and materials for growth from food. Parts of the food are indigestible and are eliminated as waste. Breathing allows people to take in oxygen, which is necessary to function. Skin protects the body from harmful substances and organisms; it also prevents us from drying out. The brain gets signals from all parts of the body dictating what is happening there. The brain also sends messages to other parts of the body to influence what they do. Each plant or animal has different parts that serve different functions. An organism s pattern of behavior is related to its environment when this environment changes, some organisms survive, while others relocate or die. All organisms must be able to maintain constant internal integrity in a changing environment. Regulation involves sensing and modulating of internal conditions. An organism s behavior evolves through adaptation to its environment. 6 8 Living systems demonstrate the complementary nature of structure and function. Organs and organ systems are composed of cells with specialized functions. Most organisms are single cells, while others, such as humans, are multicellular. Cells carry out most functions needed to sustain life. For example, food can be used as energy and building

3 blocks only after it is digested and transported to cells. Burning food releases the energy stored in it. This requires oxygen; the resultant CO 2 must be eliminated by exhalation. The human body has interrelated systems for digestion, respiration, reproduction, circulation, excretion, movement, control, coordination, and disease protection. Disease is a breakdown in structures or functions of an organism. Some diseases result of damage from other organisms, while others are intrinsic system failures. Interactions among senses, nerves, and brain make learning possible, which allows humans to adapt to changes in their environment. The urinary system disposes of dissolved waste while the intestinal track removes solid waste; the skin and lungs rid the body of excess heat. The circulatory system moves substances to where they are needed. Hormones are chemicals that affect other body part. They regulate human growth, reproduction, and responses to danger. Plants, like humans, reproduce sexually. Sexually produced offspring are never identical to either of their parents. Every organism requires a set of instructions that specify its traits. Heredity is the passing of these instructions between generations Species evolve over time. Evolution is a consequence of the potential for a species to reproduce, the genetic variability of offspring, the finite supply of resources, and the ensuing selection by the environment of offspring who are best able to survive. The diversity of organisms today is the result of 3.5 billion years of evolution. Natural selection provides an explanation for the fossil record. All organisms that live on earth today are descended from common ancestors. Biological classifications are based on how organisms are related. The immune system protects the body against microscopic organisms, foreign substances, and some cancer cells. The nervous system uses electrochemical signals; the hormonal system is responsible for chemicals that circulate in the blood. The two systems coordinate together. Cell structure is based on its function. Every cell has a membrane that separates it from the outside environment. Most cell functions involve chemical reactions breakdown and synthesis of substances is made possible by enzymes. Cell communication is necessary and occurs via chemicals, spread locally or through the blood. Some drugs mimic or block the molecules involved in these communications and disturb normal functionality of the brain and body. Reproduction is vital to the survival of any species. Sexual behavior depends on cultural, personal, and biological factors. Hereditary information is contained in genes, located in cells chromosomes. A trait can be influenced by one or many genes. Human cells contain thousands of genes. DNA is a polymer that stores genetic information. It is composed of subunits of 4 kinds (A, G, C, and T). DNA directs the synthesis of proteins. DNA mutations occur spontaneously at low rates. Some of these changes influence the organism, while others make no difference. Most cells in humans contain two copies of each of 22 different chromosomes. A pair of chromosomes determines sex: XX (female) and XY (male). A child receives one chromosome from each parent. Cell functions are regulated through the selective expression of individual genes. Plant cells contain chloroplasts, where photosynthesis occurs. Plants use solar energy to create energy-rich compounds from water and carbon dioxide. Section IV: Examine Research on Student Learning Italicized content is from Benchmarks for Science Literacy, while non-italicized content is from Making Sense of Secondary Science. Topic Adaptation Research Middle and high school students may struggle between the colloquial and the scientific

4 Evolution Fertilization Death Internal Organs Nervous System Circulatory System Digestive System Respiratory System Muscles and Skeleton Germs Plant Nutrition usages of the term adaptation. Scientifically, adaptation is not a deliberate process, but an inadvertent one. Elementary and middle school students tend to confuse non-inherited adaptations with those features inherited in a population; that is, they appeared to believe in the inheritance of acquired characteristics. Research suggests that a student s understanding of evolution is linked to general reasoning ability. Students with poor reasoning skills fail to understand conflicting evidence to their intuition or misunderstandings and consequently, retain misinformation. By the end of 5 th grade, students understand that a baby results from the fusion between sperm and egg. However, the mechanism may be unclear students may believe that the egg is required as food or protection for the sperm, or the baby exists within the egg and the sperm is the impetus for the baby to grow. Lower elementary students understand that death is irreversible and inevitable. However, they usually do not understand that death is an internal process. Around 3 rd or 4 th grade, students understand that death means the cessation of bodily functions. Lower elementary students may believe that the contents of the body are what they witness entering or exiting it i.e., food, blood. Young children may also cite egocentric explanation for parts of the body, rather than causal relationships. Upper elementary students can list many organs. Few adults know which internal organs are located where. By age 4-5, children understand that the brain is an internal body part, but think that it exists in addition to the mind. By age 10, most children understand that the brain helps certain body parts to function. By age 14, most children know that the brain is essential to all behaviors. By the end of 2 nd grade, students understand that thought is needed for motor activities; as such, they know that the brain is involved. 5 th grade students don t appear to understand the role of the brain in involuntary behavior. Upper elementary students know that the heart is a pump, but are unaware that the blood returns to the heart. Students of all ages hold misconceptions about the circulatory pattern and circulatory relationships. Research indicates these ideas are difficult to change. Lower elementary students know food is related to growth, but don t understand the physiological mechanisms. Until 9 years of age, children tend to misattribute the role of the stomach to waste and blood management. They also thought that food vanishes after it is eaten. From about 7 years of age, students understand that the stomach helps break down food. Students commonly believed that digestion releases usable energy from food (without conservation). More than half of 13-year-olds thought that enzymes are made of cells. Lower elementary students may not know what happens to air after it is inhaled, while upper elementary students may associate the lungs with breathing and the exchange of gases. Children do not relate muscles to meat. Younger children understand that muscles support the skeleton, while older also understood that muscles are necessary for movement. Students do not understand the role of muscles in other bodily systems. Elementary students may believe that all illnesses are caused by germs, possibly the same kind of germ, and that any infection in the body makes it ill. Medicine is thought to induce healing immediately. A non-trivial number of 13 and 14-year-olds believe that plants get their food from the soil and that roots are an organ for feeding. More than 70% of 11-year-olds believed

5 Responses of Plants that plants feed similarly to humans. Most secondary students understand that isolating a plant from sunlight will retard its growth.