Life Science Lessons
• Experiment and Discover-CLONED...Learn how to make scientific discoveries using the scientific method. When you follow these steps, there's no telling what you might find out!
• Find and Track Animals-CLONED...We can learn more about animals by watching them. Both art and science are a part of animal tracking. We can search for paw prints in the snow, we can look at damaged plants, and we can pick through the remains left behind by animals to help us guess the how an animal acted and where they went. Cameras are often used to observe animals without them knowing we are there. These are called critter cams. We can take pictures and video to help us learn more about how animals live and move.
• Animal Families - c...The world is full of many different types of animals. We can group them by size, color, texture, habitat, and more. There are millions of kinds of animals. Scientists are always working to find new animals. Meanwhile, various groups work hard to protect the current species that we do know.
• Warm Blooded Animals-CLONED...As you walk outside, look around. Listen. What do you see? What do you hear? You might hear the chirping of a robin, the skittering of a squirrel, the bark of a dog, or even the quick of a duck. It seems like birds and mammals are everywhere we go. However, birds and mammals are the smallest groups of animals in the animal kingdom. Some animals, such as the white-tailed deer, brown bear, and sea otter live in just about any local zoo. Other animals, such as the koala, kangaroo, kingfisher, and the wallaby live only in other parts of the world far away. More and more construction cuts down on many of the habitats in which birds and mammals live in the wild. This has caused many species to become endangered. We need to all work together to preserve the environment for all animals to live.
• Cold Blooded Animals-CLONED...Fish, amphibians, and reptiles group of animals. They can adapt to live in many different environments. They are important and valuable members of the world. Fish include the classic types of fish we see in ponds and aquariums, but sharks and stingrays are also fish. Frogs, salamanders, and newts begin life in the water as tiny eggs and then grow legs and move on to the land. Reptiles are rough-skinned creatures. Lizards, crocodiles, snakes, and turtles are all reptiles.
• Hard and Soft Animals-CLONED...Mollusks, worms, echinoderms, and arthropods are all amazing animals. The mollusks have soft bodies and grow beautiful shells to protect themselves. Humans use the shells in many ways. Worms are more than just slithery, slimy creatures. They are able to perform amazing jobs such as creating air in the soil and breaking down garbage. Echinoderms have spiny skins and can grow back any of their body parts. Arthropods are the largest group of all animals. Insects live everywhere on Earth. They have six legs. Spiders have eight legs and lobsters have ten or more legs.
• Life In and Around Water-CLONED...Texas is the home to many plants and animals. A large number of these organisms live in water communities. The water environments are very different from place to place within Texas. There are rivers, streams, ponds, lakes, and even the huge Gulf of Mexico. They are the homes for many of the animals and plants in Texas.
• Fixing the Ozone Hole-CLONED...Human use of certain types of chemicals has created a massive hole in the ozone layer, which protects the earth from the sun. Find out what is being done now to fix it.
The Cycle and Structure of Life
• The Life Cycle...All organisms go through a life cycle. Some living things, such as humans, cats and dogs, start life looking similar to what they will look like as adults. Other organisms, including plants and butterflies, undergo major changes as they mature. Every organism is adapted to live in its environment, and the stages it goes through as it gets older are a reflection of this, and as organisms grow and develop, they are better prepared to defend themselves. Once living things become adults, they are able to reproduce, continuing the cycle of life.
• Life's Structure...Different organisms use different structures to accomplish the activities that enable them to survive. For instance, humans use their arms and hands to get food and put it into their bodies. Plants use roots to absorb water needed to make their food. Over time, changes have occurred in structures and processes of living things. Some living things that have experienced these changes, or adaptations, have survived and reproduced in their environments. Living things that do not have structures that are helpful in one place either move to another place or die, and their species becomes extinct.
• Life Continues...In order to keep a species living on the planet, organisms produce offspring of their own kind. All organisms reproduce. Plants and animals all create new plants and animals. They reproduce through different methods. Each organism is made up of special organs or parts that help it reproduce.
• Heredity...Every living thing on earth is part of the circle of life. This includes plants, animals, and humans. Parents produce babies; babies grow up and produce their own children. This cycle continues indefinitely, thus contributing to the great circle of life. Similar characteristics, or traits, are passed from parent to offspring. This is called heredity. We measure and understand heredity by units called genes. Each parent gives you one half of your genes. Genes make you the extraordinary person that you are. There is no other person in the world that is just like you.
• The Diversity of Plants...In this lesson, we will learn about many different kinds of plants. We will look at some ways other living things use plants. We will meet some very special plants and see why we should protect them.
• Plant Anatomy and Reproduction...We do not usually think of plants as having bodies like we do, but if you look at a plant, it is easy to see that most of them are made of different parts. While most people can name different parts, such as roots, leaves, stems, or petals, it is also important to learn about the jobs of each of these plant parts. Some plant parts have the job of getting food to the right parts of the body, while other parts help the plant reproduce. Not all plants have the same parts or design to their body. These differences can affect where a plant can grow, survive, and reproduce. Our lesson begins by looking at plants from a new point of view.
• Introduction to Animals...Scientists group animals together according to various characteristics under one classification system that all scientists around the world use. This classification system is called taxonomy. While some animals fit clearly into one classification or another, it is not always so simple to place other animals into one specific group. Numerous animals have adapted to their changing environments over time and successfully maintained their populations. However, other animals are not so fortunate and therefore we have witnessed several species become endangered, even extinct. While there are millions of species yet undiscovered, it would be tragic to lose a species forever.
• Animal Groups...The world of animals ranges from very basic, single-celled organisms such as protists and amoebae to the complex mammal, the human being. Within that range, you will find a massive array of fascinating creatures. With every body type, behavior pattern, and living style imaginable, a plethora of animals await discovery. While biologists continue to hunt for new species, we can study the exceptional creatures that we have already discovered. Joint-legged arthropods, soft-bodied mollusks, swift-swimming cephalopods, and prickly echinoderms are all invertebrates. Vertebrates include amphibians, reptiles, fish, birds and mammals. Within all of these animal groups is a fascinating range of differences. Each animal has its own unique body structure, behaviors, living environment, and abilities. Humans are the most sophisticated of all animals, and one of our most intense curiosities is to learn about all of the animals around us.
Interactions of Life
• The Behavior of Living Things...Life begins with cells containing information within them, called DNA. DNA is called “the code of life” because it tells the cells what proteins to make to keep the organism healthy and in good repair. Some animals have changed over time because nature has changed around them. These changes include skin and outer covering colors, alterations in behavior, adaptations in movement, and changes in geographic location and diet. Living things respond to what is happening around them in their environment, such as light, temperature, gravity, heat, water, and pressure. Animals respond to these in order to survive. Living organisms like their system to be in balance. They often move to other areas when their home becomes too hot, too cold, or if food becomes scarce. Sometimes, different beings live together to keep this balance. When this happens, both animals can help each other, or one or both animals harm each other. Scientists cannot decide what makes living things do what they do when they do. Some think that their DNA decides everything, while others think that what happens when an animal was young decides behaviors. Still others believe that it is a combination of both.
• Living Relationships...For living things to stay alive, they must face many tests. Finding the basics needs of food, water, shelter, and space is not enough. One of the most common relationships is between living beings who can make their own food and those who cannot. Producers can make their own food while consumers eat what the producers make. Plants produce their own food by trapping the sun’s energy. They mix carbon dioxide and water with the sunlight to build sugars. In turn, consumers eat the sugars created by plants. Consumers are classified as herbivores, which eat plants, carnivores, which eat meat, and omnivores, which eat both plants and meat. Food webs and chains show how living things survive in relation to each other. All food chains start with sunlight that plants trap and turn into sugars. All food chains end with decomposers which break down dead materials. A simple chain shows how predator and prey act together. A predator is a creature that eats others. Prey is what is eaten by the predator. For example, a rabbit eats plants, and a wolf in turn eats the rabbit. When the wolf dies, decomposers break down its remains. Many living things live together in a close relationship known as symbiosis. Sometimes, both living things are helped; other times, one is harmed because of the living together. These relationships occur in biomes, which areas that have all these different types of plants and animals living and interacting in specific environments.
• Living and Nonliving Connections...Civilizations across time have investigated livings things. They have attempted to understand how and where they live, how they relate to each other, and how they behave. Scientists now recognize that living organisms are dependent on both the nonliving and living features of a habitat. The elements around us, such as trees, soil, water, and air, form all living organisms. Some of these primary components include nitrogen, oxygen, carbon, and phosphorus. All of these are recyclable and constantly interchange between living and nonliving entities. All life begins with energy from the sun. Plants capture the sun's energy and use it to make food. They are the basic food source for all living creatures. Other organisms rely on plants this primary source in different ways, organized in the food chain. These organisms live in all sorts of arrangements, including niches, habitats, ecosystems, which all form the larger arrangements called biomes. Within all these systems, there are producers, those organisms that can photosynthesize, consumers that eat the producers, and decomposers that break down living materials into the original inorganic elements. The world is composed of a hierarchy of environments called biomes. Examples of biomes include forest, desert, grassland, tundra, and mountain, among others. In all these environments, organisms establish themselves as producers, consumers and decomposers. Biomass is the term for plant material or agricultural waste used as a fuel or energy source. It may eventually be used as a fuel source and possibly even replace some fossil fuels.
• Preservation for Continuation of Life...Every creature is connected to all others in a system known as an ecosystem. Plants supply food, water, and shelter. Plants depend upon animals for such processes as pollination and breaking down necessary nutrients. Animals are part of complex food webs, chains, and pyramids that rely on a balance in the predator-prey relationship. The way in which living and non-living components interact comprise what is called an ecosystem. Some of these factors include precipitation, sunlight, ground covering, and temperature. The design of these interactions allows certain organisms to thrive; this is called the carrying capacity. Limiting factors, such as food, water, shelter, and space control population size. This usually results in the fluctuation of various populations over time. Natural disasters are a major factor that can also cause dramatic and immediate changes in populations. Ecosystems provide both renewable and nonrenewable resources. Human interactions with these resources often have devastating effects. With time and effort, humans have begun to recognize the warning signs of a deteriorating ecosystem. Environmentalists have created a variety of solutions, including recycling, reducing, conserving, and reorganizing landfills. These efforts are world-wide and our hope is to see the Earth’s valuable resources renewed to sustainable conditions.
Middle School Lessons
• Tracking Animal Movement-CLONED...Learn how scientists and animal enthusiasts track the movement of animal species by using advanced technology...or simply by looking for signs the old-fashioned way.
• Aquatic Life in Texas-CLONED...Texas is home to a diverse set of plants and animals living in or near water. Learn more about these aquatic species and their unique adaptations.
• The Scientific Method...Most people are naturally curious. If you like asking questions and finding answers, you would make a good scientist. Learn how you can use the scientific method to find answers to almost anything.
• Classifying Animal Life-CLONED...The world is full of many different types of animals. Only by grouping and classifying can we record and account for all of the species.
• Birds and Mammals-CLONED...Birds and mammals represent only a fraction of all animal life on the earth, but humans have more in common with them. Find out what makes them special.
• Fish, Amphibians, and Reptiles...Fish, amphibians, and reptiles are the most adaptable animals on the earth, able to thrive in even the harshest environments.
• Worms, Mollusks, and More-CLONED...Mollusks, worms, echinoderms, and arthropods are among the most strange and remarkable groups of animals on the earth. Find out what makes them special.
• The Ingredients of Life-CLONED...Life is an intricate chain, with each form linked in some ways to the others. Learn about the important relationships that keep us all alive.
• Preserving Animal Life-CLONED...As earths human population continues to grow, it becomes all the more important for us to ensure the survival of other species. Find out what it will take and how you can participate.
• Scientific Inquiry...When does an idea or discovery become a scientific fact? Never, really. But methods of scientific inquiry can be used to determine the best explanation. Learn how to apply the principles of scientific reasoning.
• Monitoring Animal Populations-C...Biologists who study animal species must be able to observe, count, and sometimes even relocate the animals. They need to be good at tracking. Learn what it takes to track and identify animals by the signs they leave behind.
• Ways Animals Communicate-CLONED...Humans use speech to communicate, but we also communicate non-verbally. How would you convey without words that you are upset, that you love the taste of sushi, or that you want someone to follow you? Animals use many different forms of communication. Learn about some of them.
• Studying Animal Behavior-CLONED...You know what it means to be on your best behavior, but behavior can be anything you do. Even sitting and doing nothing is a behavior! Biologists study animal behavior to learn more about them and, hopefully, help them survive. Learn about the study of animal behavior.
• Laboratory Research Methods-CLONED...Doctors use laboratories to help them care for human patients. Laboratory tests can show if someone is healthy or has a disease. Zoos also use laboratories to help them care for animals and do research. Learn more about laboratories.
• Bats!...Did you know that without bats, we might not be able to enjoy some of our favorite foods such as peanut butter, chocolate, bananas, bread, French fries, ketchup or orange juice? There are over 1,100 species of bats, and they live on every continent except Antarctica. Only 3 species of bats suck blood. Most (70%) eat insects. The other 30% of bats eat fruit, pollen, or nectar, or are carnivores. Most of what we eat comes from plants. Bats help provide us with these foods, and many other products, by eating insects that destroy certain plants, by pollinating plants and dispersing seeds, and even by providing fertilizer. Bats also help keep humans healthy. We obtain 80 different medicines from plants that rely on bats for their survival. Bats keep us from getting sick by eating disease-carrying insects, such as mosquitoes which carry malaria and West Nile virus. Bats also protect the environment; if bats were not around to eat so many insects, we would have to use many more harmful pesticides, which can harm animals, including us!
• Cats - Overview...Zoologists place cats in to either big or small categories based on characteristics other than physical size. The throats of small cats are designed to purr continuously, but not roar. Big cats can roar but not purr. Purring and roaring each have specific purposes. The pupils of Big cats close to a circle, while most small cats’ pupils close to a slit. Smaller cats that are domesticated have many similar behaviors and characteristics as their wilder counterparts. They make good pets but some housecats that return to living outdoors become feral which is not quite wild but not quite the kitty purring on your lap. Cats of all shapes, textures, behaviors, and backgrounds are fascinating creatures and the subject for many researchers.
• Small but Fierce -The Small Cats...The small wild cats can be found all over the world including: Africa, Asia, China, Europe, Indian subcontinent, Mediterranean, Russia, United Kingdom. They live in high-altitude mountain ranges, jungles, deserts, and forests. Compared to other carnivores, very little is known about the small cats. They are elusive animals and very difficult to study in the wild. The destruction of natural habitat, poaching, and diseases all contribute to a severe threat to the wild cats' populations. Efforts are in effect to conserve the wild cats' numbers but the task is challening due to lack of funding.
• Saving the Ocelot - Felis pardalis...Ocelots were highly prized in the 1970s in the Western fur trade. By the mid 1980s, the ocelots were nearly extinct. Concern over their extreme decline in numbers played a role in the formation of the 1975 Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). By the end of the 1980's the ocelot fur trade significantly decreased. Ocelots remain on the endangered list in the United States due to their continued decline as a result of habitat loss. Today ocelots can be found in southern Texas where they are protected.
• Big and Bold - The Big Cats...'Big cat' is the informal classification of lions, tigers, leopards, and jaguars. It is not a scientific classification as these cats share many similar biological characteristics as the smaller cats. However, they have certain physical features that set them apart. The big cats have suffered declining populations due to a variety of reasons. climate change, habitat loss due to deforestation and pollution, and poaching are some of the major factors that affect the big cat numbers. Conservation efforts are in operation around the globe the aim to assist in the reversal of the big cat numbers. This is an arduous battle as it is important for nations to universally get behind these efforts to preserve the environment for the cats.
• Texas Communities and Biomes...Texas is a big state with diverse environments: prairie, forest, desert, beach, etc. Learn about the animal species that struggle and thrive in the many biomes of Texas.
• Texas Plant Diversity - c...In a state the size of Texas, you would expect there to be a lot of plant species. You would be right! Learn about the diversity of plant species in Texas.
• Texas Animal Diversity - c...The sheer size and geographic location of Texas means the state has many diverse environments and a wide variety of animal species. Learn about the many kinds of animals that call Texas home.
• Texas Aquatic Communities - c...When you think of animal diversity in Texas, aquatic species may not come first to mind. But from its wetlands along the Gulf Coast to the many rivers and lakes of its plains, Texas is home to many aquatic species. Learn about a few of them.
• Texas Geology - c...At its surface, the diversity of the state of Texas is evident. In this lesson you will learn about the geological forces that shape the landscape of Texas, as well as the minerals that impact its economy.
• Animal Classification-CLONED...The world is full of many different types of animals. Only by grouping and classifying can we record and account for all of the species.
• Mollusks, Worms, Arthropods, Echinoderms-CLONED...Some animals have physical features similar to humans: two eyes, two ears, four limbs, and warm blood, to name a few. Many more animals are nothing like us. In this lesson you will learn about some of these amazing and very different creatures.
• Fish, Amphibians, Reptiles-CLONED...Earth's original residents were fish, amphibians, and reptiles. Some of these prehistoric animals – sharks, turtles, and alligators, among others – are still around today. Learn about some of these enduring species.
• Birds and Mammals-CLONED...Birds and mammals are the most loved animals by humans (who are also mammals). Some have been domesticated and have evolved to have working relationships with humans. Learn more about our animal cousins.
Interactions of Life
• Living Relationships-CLONED...An important key to understanding life on earth is to recognize the relationships between life forms. For example, a plant may provide food and shelter for an animal, which in turn protects and nourishes the plant. Learn about some of these amazing relationships.
• Preservation for Continuation of Life-CLONED...Every creature is connected to all others in a system known as an ecosystem. Plants supply food, water, and shelter and depend upon animals for pollination and breaking down necessary nutrients. Animals are a part of intricate food webs, chains, and pyramids.
• Humans and Erosion-CLONED...The human causes of soil erosion are simple to understand, but are difficult to fix. How do we stop beaches eroding due to man-made structures such as seawalls? Do we stop building seawalls and homes on the beach? Or do we spend more taxpayer money for more expensive solutions such as beach renourishment? How do we stop poor farmers worldwide from practicing farming techniques, such as slash-and-burn, that erode the soil when they have families to feed? Who will pay for the education and training they need? As you can see, the problem of human and soil erosion does not have a simple solution, and it will be up to future leaders worldwide to continue working on this complex issue.
• Human Effect on the Ozone-CLONED...Ozone is a naturally occurring chemical in the stratosphere that serves to protect the Earth. Human activities, though, have affected this protective layer. The use of CFC's in aerosols, air conditioners, and refrigerators, just to name a few, has contributed to the destruction of protective ozone. The destruction of the ozone layer will have serious consequences for both humans and the environment. The Montreal Protocol brought many countries together to form an agreement to ban the use of CFC's, with hopes that the ozone layer will repair itself.
The Basic Units of Life
• Types of Cells...A cell is defined as the smallest part of any living thing. The discovery of its existence is thought to have occurred in the late 1600s. Anton van Leeuwenhoek created microscopes and began to observe tiny living things in pond water, which had not been seen before. He christened these things "animalcules". He also observed bacteria, protists, sperm cells, and blood cells. Robert Hooke studied cork under a compound microscope, eventually naming the “little boxes” cells because they reminded him of the cells of a monastery. Over the next 200 years Matthias Schleiden, Theodore Schwann, and Rudolf Virchow in 1858 combined thoughts to devise the cell theory. Cytology is defined as the study of cells and cytologists are those scientists who study cells. Cytologists have discovered that all cells contain similar elements such as carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur. Beyond these similarities, cells are incredibly diverse and serve multitudes of purposes.
• Functions of Cell Parts...Throughout time, thoughts and ideas about life have formed and evolved. Originally we hought life arose from nonliving matter. With a great deal of time and effort, we now recognize that living cells must come from existing cells. The cell is one of the most basic units of life and is often entitled the building blocks of all living matter. There are numerous types of cells that can exist and survive alone while others assemble to perform specific functions. Almost all cells contain a combination of the following organelles; cell membrane, cell wall, cytoplasm, nucleus, mitochondria, chloroplasts, ribosomes, endoplasmic reticulum, chloroplasts, vacuoles, and lysosomes. Organelles are those structures that carry out everyday processes most of us take for granted.
• Cell Processes...Cells must carry out many processes to ensure healthiness and maintain suitable conditions for survival. Photosynthesis and respiration are interconnected because photosynthesis traps sunlight and creates the sugars needed by all living organisms. Cellular respiration utilizes the sugars created by photosynthesis to provide energy. Cells use two distinct methods for creating new cells for growth and repair. This is accomplished via mitosis during which one cell divides into two identical cells. Meiosis divides the number of chromosomes in half to guarantee genetic accuracy. To keep from failing, cells must control what exits and enters the cells. Passive transport allows materials to enter cells without application of energy; active transport is identical to passive with the exception that it requires energy. Endosytosis allows materials to enter cells without a membrane; exocytosis allows materials to exit cells without a membrane.
The Codebook of Life
• Introduction to DNA and RNA...Over time, many chemists, physicists and biologists discovered and contributed to the blueprint and structure configuration of DNA. However, it was in 1962 that James Watson, Francis Crick, and Maurice Wilkins collected the Nobel Prize in physiology/medicine for proposing the actual structure of DNA. Watson, Crick, and Wilkins suggested that the structure of DNA is a double helix, much like a ladder that is twisted into a spiral shape. The bases of the DNA are found in pairs, which make up the rungs of the ladder. The sides of the ladder, made of phosphates and deoxyribose (sugars), are the structural backbone of the DNA. They don't transmit information; they just hold the bases in their proper order. DNA bases characteristically pair G with C, and A with T. DNA is located in cells' nuclei of which every living organism consists. This information is found in chromosomes that exist in the nucleus of your cells. The nucleus has a nuclear envelope with minute pores to maintain its integrity and allow movement of materials. Inside this nucleus or nuclear area are chromosomes, which are long strands of DNA that contains certain sequences of genes. These genes carry the genetic information of the cell. Genes are portions of the DNA strand that tell the body what proteins to make to ensure the health and rebuilding ability the living creature.
• Chromosomes and Genes...More than likely you have noticed that you share characteristics with your family members. DNA, found in the nucleus of each cell, is wrapped into coiled structures called chromosomes. That DNA holds the codes for your traits. Chromosomes, in turn, are divided into portions of genetic material that regulate production of proteins manufactured for the proper health of a living system. Living things are constructed from many different types of cells such as those in the heart, eye, nerve and bone. All of the cells hold the same chromosome but perform different functions. And, not all genetic material is active at the same time. Occasionally, the genetic message is altered or mutated, in some way due to exposure to radiation, certain foods, multiple copying of extensive strands of DNA, or simply aging. Variations could result in deleting, reversing, or inserting nitrogen bases. Most changes are irrelevant, but some can create the foundation for genetic disorders or syndromes, which disrupt the normal functioning of a living system.
• Passing the Code...For living organisms to continue existing on this Earth, they must reproduce by bestowing their genetic information to the next generations. Some animals reproduce by asexual reproduction. This method involves passing identical genetic information to subsequent generations. Organisms accomplish this by such processes as budding, regeneration, and binary fission.
Patterns of Change
• Heredity...DNA is an important molecule of all life. It determines who you are, what you look like, and even your health. But long before DNA, we understood and could predict some of the traits an organism might end up with. These principles of genetics came from Gregor Mendel. By studying pea plants, he discovered that traits have two forms, called alleles, which can be dominant or recessive. Scientists now make predictions of the genes that offspring receive, called the genotype, as well as the appearance or phenotype of the offspring, by simply using a Punnet square. Pedigree charts are useful for tracing the history of a trait from one generation to the next. Today, the study of genes has uses far beyond what Mendel could have ever imagined when he was studying his pea plants, such as gene therapy, genetic engineering, and even cloning.
• Evolution...“It is not the strongest of the species that survives, nor the most intelligent that survives; it is the one that is the most adaptable to change.” This quote is from a book that changed scientific thought permanently and began a debate between people from many different backgrounds that continues today. The book, Origin of the Species, was written in 1859 by an English naturalist named Charles Darwin. Darwin was not the first to propose a theory of evolution, or change over time, but his theory is the one that has withstood the tests of science.
• Classifying and Exploring Life...All life that has been currently identified and studied is placed into one of six kingdoms. Single-celled Eubacteria are found in every imaginable environment. Humans depend on bacteria, but are also affected by them with many diseases. Even older and smaller than Eubacteria are the Archaebacteria, primitive life forms living in only the most extreme environments on the planet. The primary difference between these two kingdoms and the other four is based upon cell structure. Plants, animals, fungi, and protists all have a nucleus in their cells, whereas bacteria do not. These life forms also tend to be more complex, with those that consist of more than one cell organizing themselves into tissues, organs, and organ systems. All of these kingdoms contain millions of species and represent the vast biodiversity of our planet.
To Be or Not To Be a Cell
• Viruses and Bacteria...Have you ever taken antibiotics when you were sick? Have you ever thought about what might be surrounding you when you go swimming in the ocean or local pool? Organisms that require a microscope to be seen are called microorganisms. During this lesson we will focus on two types: bacteria and viruses. Keep your eyes open; you are about to go searching for a particular one!
• Protists and Fungi...When you wade in the creek, you are surrounded by tiny creatures that you cannot see. Some are very interesting to watch on a microscope slide and others can make you very sick. These living things belong to a kingdom called Protista. Most of them are made of only one cell. Some, like plants, can make their own food while others must eat like animals do. The other kinds of living creatures we will see in this lesson have good varieties that we eat and bad ones that we hope do not grow on our feet. The mushrooms on our pizza and athlete's foot are caused by living things that belong to a kingdom called Fungi. When we see fungi in our yards or growing on something that has been in the refrigerator for too long, we might think of it as some kind of plant material, but a fungus cannot make its own food and must live off a plant or animal. Even if you detest mushrooms and you have never had some kind of rash because of a fungus, you will see in the following lesson that there is a good chance that Protists and Fungi have been a part of your daily life in many ways.
The Multicellular Synthesizers
• The Diversity of Plants...Many different kinds of plants play a part in our daily life on planet Earth. We can eat plants, wear clothes made from plants, or give them as gifts. When we visit new places, we can discover new kinds of plants that live in habitats that are different from ours. Plant life began in the water and through many years of evolution developed ways to solve problems that come with living on land. As you move through the following lesson, think about why having different kinds of plants on Earth is important.
• Plant Anatomy...We do not usually think of plants as having bodies like we do, but if you look at a plant, it is easy to see that most of them are made of different parts. While most people can name different parts, such as roots, leaves, stems, or petals, it is also important to learn about the jobs of each of these plant parts. Plant cells have special parts that allow the plant to have a firm structure and to make its own food. Special plant tissues have the job of getting food to the right parts of the body. Most flowers contain parts that can make both male and female reproductive cells. Not all plants have the same parts or design to their body. These differences can affect where a plant can grow, survive, and reproduce. Our lesson begins by looking at plants from a new point of view
• Plant Reproduction...Wow! The college students are sorry you got caught in their unauthorized experiment, but they sure hope you enjoyed your tour of plants and will share the information with your classmates. It is amazing to stop and think about how similar our bodies are to plants in some ways. Humans and plants have cells that gather together to form tissues. Those tissues then form different organs such as leaves, or a leg. Isn't it fascinating how many layers there are to a leaf when they appear so thin? Next time you eat a salad, you will know whether or not it contains roots, stems, leaves, fruits, seeds, or all of the above! Plants cannot move around and choose a mate like animals can, but they have seeds that come in all shapes and sizes that can be spread out, or dispersed by wind or animals, and just like animals, plants use egg cells and sperm cells to reproduce. We also both have to keep a certain amount of moisture in our bodies. Both types of living things need a certain amount of time to grow and develop. Now that you know so much about plants, maybe you can visit a local garden or park and look for the parts and processes which you have seen today.
• Introduction to Animals...A trip to the zoo, a visit to the ocean, a hike in the mountains, even a walk through the park reveals a vast array of animals that live around us. Some animals have skeletons and others are gelatinous blobs; some have wings while others have flippers; some breathe with lungs whereas others take in oxygen through highly structured gills. The collection of these diverse organisms comprises the animal kingdom. Scientists group animals together according to various characteristics and have developed a universal, highly sophisticated classification system, called taxonomy. While some animals fit clearly into one classification or another, it is not always so simple to place other animals into one specific group. Numerous animals have adapted to their changing environments over time and have successfully maintained their populations. However, other animals are not so fortunate and therefore we have witnessed several species become endangered and even extinct. While there are millions of species yet undiscovered, it would be tragic to lose a species forever.
• Mollusks, Worms, Arthropods, and Echinoderms...Mollusks, Cephalopods, and Echinoderms are truly remarkable living organisms. Within each phylum are thousands of intricately designed animals that never fail to astound scientists. Using physical and chemical assets, these animals have learned to live with and protect themselves from one another. Through shells, spines, ink, slime and enzyme secretions, enhanced brain systems, segmented bodies, regenerative abilities, and other such amazing characters, they have truly set themselves apart from the other members of the Animal Kingdom.
• Fish, Amphibians, Reptiles...Some of the Earth's most unique and readily adaptive organisms are fish, amphibians, or reptiles. These animals are present in every environment, even the harshest locales. Invaluable members of the world's ecosystem, they are at great risk of decline and eventual extinction due to the destructive activities of humans. We need to take part in protecting the habitats that these creatures live in.
• Birds and Mammals...While we can observe many of the species of birds and mammals in zoos, wildlife exhibits, and in regulated safaris, they represent only a fraction of all of the species of birds and mammals in the world. Some animals, such as the white-tailed deer, brown bear, and sea otter reside at just about any local zoo. Other animals, such as the koala, kangaroo, kingfisher, and the wallaby are indigenous to other parts of the world and we therefore may only have a rare chance to encounter them. With the rapid expansion of industrialization in an ever-growing world, the natural habitats for many of these animals are disappearing. This has placed several species at risk of endangerment. There are efforts to protect the Earth's ecosystems, but we need to do more before we lose certain species forever.
Keeping the Inside Strong
• Structure and Movement...The skeletal and muscular systems permit the body to remain upright and in motion. At birth the human skeleton is designed primarily of cartilage that eventually fuses into bone. The axial skeleton comprises the skull, ribs, and sternum. The appendicular skeleton consists of the bones located in the shoulders, pelvis, and attached limbs. Each bone has three major sections: compact, soft bone marrow, and spongy bone. While the skeleton may seem nearly indestructible, it can rupture. The skeletal system would be useless if the muscular system did not work in concert to allow movement. Three different kinds of muscles are found in vertebrate animals: cardiac muscles found in the heart, smooth muscles in the walls of all the hollow organs, and skeletal muscles attached to the bones. Joints are defined as a point where two or more bones connect permitting bending, swiveling, stretching, and pivoting. They are categorized as moveable, such as ball-and-socket, hinge, gliding and pivot and immovable, such as bones of the skull and pelvis.
• Circulation and Respiration...The respiratory and circulatory systems complement each other to exchanges gasses and transport materials. The respiratory system consists of lungs, bronchi, diaphragm, trachea, alveoli, throat, mouth, and nasal passages. The circulatory system is comprised of the heart, blood vessels and blood functioning together to transport oxygen and carbon dioxide, clot blood, and fight infection. The heart is divided into four sections: two atria and two ventricles. The lymphatic system is also involved in the circulatory system, providing assistance in the body's defense system by filtering out unwanted organisms that cause disease.
• Digestion and Excretion...The digestive system breaks down food into usable products for the body by means of enzymes and digestive juices. Digestion begins in the mouth with the teeth, tongue, and salivary glands. Once food is swallowed down the esophagus via peristalsis, it plummets into the stomach where it is further processed. The material then passes into the small intestines where the usable materials are absorbed. Unfortunately, not everything that is eaten is digestible. In addition, waste products are created during everyday processes required to keep us alive. Both products exit the body through the excretory system. Liquid waste, or urine, is processed in the kidneys that filter blood and remove toxins. That waste is sent to the ureters, tubes leading from the kidneys, and into the bladder. The bladder then releases the urine through the urethra. Solid wastes are processed in the large intestine, stored in the colon, and then removed through the rectum and anus.
Sending and Receiving the Right Signals
• Nerves, Skin, and Senses...The nervous system, skin, and five senses are entirely interconnected. The nervous system's job is to gather information and transmit it to the suitable body part. The ultimate job of the system is to maintain all other systems and preserve the healthy and safety of the organism. It is divided into two parts: the central and peripheral systems. The central nervous system consists of the brain and the spinal cord. This system then processes information to transmit messages through the peripheral nervous system, which connects the central nervous system to the rest of the body. Information travels along neurons, cross a synapse, and elicits the proper reaction. The skin is the largest organ of the body and has many different functions. The skin maintains our body temperature, protection against invading pathogens, and sweating. It also provides the first indications of the outside environment characteristics. The five senses provide detailed information about the world around us. Sight develops a visual representation; smell detects odors and scents; taste distinguishes between sweet, sour, salty, and bitter; touch elicits words such as soft, smooth, rough, bumpy; and hearing allows us to perceive sounds.
• Hormones and Reproduction...Male and female endocrine structures are different, yet designed for similar purposes. Endocrine glands secrete hormones that make other cells perform different functions, attempt to balance stress, and create mature male and female body forms. The male's reproductive system is designed to create produce and release sperm into the female's body for the express purpose of reproduction and the continuation of the human race. Organs include the prostate gland and epididymides, vasa deferentia, seminal vesicles, seminal fluid, the prostate glands, and Cowper's glands. Outside the body are the penis and the scrotum. The female's endocrine system is designed to equip the body to produce and release eggs, with the express purpose of carrying a child and eventually giving birth. Organs include the vulva, the vagina, the uterus (or womb), the fallopian tubes, ovaries, and breasts.
• Immunity and Defense...Invaders, who would like nothing more than to make us ill, bombard the human body daily. Most of those trespassers are harmless, but some are deadly. The immune system is the body's defense against such pathogens such as bacteria, viruses, germs, and allergens. The system is delicate, but extremely well directed, involving a variety of organs, tissues, and cells. Its ultimate goal is to protect and keep us healthy. On occasion, the system fails, resulting in illness. The immune response shifts objectives to destroying what has assaulted our body. It can receive assistance by resting, drinking plenty of fluids, and using medications when necessary. Several cells flow through our bodies as a primary line of defense. These include the white blood cells, or leucocytes. Their sole purpose it to find and destroy disease-causing agents. The phagocytes eat pathogens, and lymphocytes help the body to remember and recognize previous prowlers. Neutrophils fight bacteria, B cells search and label the targets, and T cells destroy what the B cell has labeled. The technical name for a foreign substance is an antigen. B cells produce antibodies that connect to the antigen. The antibodies remain in your system to protect against any subsequent invasions of that specific antibody. Several types of immunity also aid in the body’s protection. Infants receive innate immunity at birth from their mothers. Active immunity develops as people contact and experience specific illnesses or receive vaccines.
• The Behavior of Living Things...Life begins at the cellular level, specifically within the chromosomes that carry genetic blueprint for structure and function. Over time, chromosomes that code for certain traits have disappeared and new ones emerged primarily through the process of natural selection and adaptations. These adaptations have brought variations in skin and outer coating colors, behaviors, habitats, and food preferences. Living things respond to their environment in a myriad of ways. Stimuli are those actions that evoke a response, causing changes in behavior, growth, reactions, and abilities. Living organisms can and do react to light, temperature, gravity, heat, water, and pressure. The ultimate goal of these behaviors is survival. Living organisms prefer for their system to be in homeostasis, simply defined as the organisms’ ability to maintain a proper balance for processes necessary for life to function. The behaviors of hibernation, torpor, estivation, and diapause assist in maintaining homeostasis when environmental conditions are unpleasant. Commensalism, mutualism, and parasitism are behavioral relationships that combine two or more species for specific purposes. As with any scientific theory, conflict arises when discussing what determines characteristics and shapes living organisms- is it nature or nurture?
• Living Relationships...Food webs and chains illustrate living organisms' relationships with animals. For living organisms to survive, they must face countless obstacles. Just locating the basic needs of food, water, shelter, and space is not enough. One of the most common relationships between living organisms is the producer/consumer connection. Living organisms can be classified into producers and consumers. Plants obtain their energy directly from sunlight, and undergo photosynthesis. In turn, animals consume the sugars synthesized by plants. Consumers are classified as herbivores, which are mainly plant eaters, carnivores, which consume mainly meat, and omnivores, which dine on both plants and animals.
• Living and Nonliving Connections...Scientists understand that living organisms are dependent on abiotic factors, nonliving features of the habitat, and biotic factors, which are living ingredients. Living organisms are created from the same elements as all other components of an ecosystem. All these elements are recyclable and move through both living and nonliving factors. Life begins with energy from the sun, an abiotic factor. Plants capture the sun's energy and use it to manufacture sugars, which are the ultimate food source for all living creatures living in niches, habitats, ecosystems, and ultimately biomes. Biomass is the term given to plant material or agricultural waste used as a fuel or energy source. This biomass will eventually be used as a fuel source theoretically replacing some fossil fuels. The world is composed of a diversity of environments technically termed biomes. In all these environments, organisms organize themselves as producers, consumers, and decomposers that all rely on abiotic factors.
• Sharing and Protecting the Earth's Resources...Every creature is connected to all others in a system known as an ecosystem. Plants supply food, water, and shelter and depend upon animals for pollination and breaking down necessary nutrients. Animals are a part of intricate food webs, chains, and pyramids. Ecosystems are designed to allow certain populations to flourish. Limiting factors, such as food, water, shelter, and space, control populations. Natural disasters can also cause dramatic and immediate changes in populations. Ecosystems provide resources, both renewable and nonrenewable. Humans have interacted with these resources, often with devastating effects. Solutions include: recycling, reducing, conserving, and reorganizing landfills and ensuring they are in place all over the world.