1-3: Studying Life

Editor's Notes

• #4: Biology - The study of life -or- the science that seeks to understand the living world Characteristics of living things Glogster
• #5: Reproduction All living things are capable of reproduction. Reproduction is the process by which living things give rise to offspring. Reproducing may be as simple as a single cell dividing to form two daughter cells. Generally, however, it is much more complicated. Nonetheless, whether a living thing is a huge whale or a microscopic bacterium, it is capable of reproduction. Growth and Development All living things grow and develop. For example, a plant seed may look like a lifeless pebble, but under the right conditions it will grow and develop into a plant. Animals also grow and develop. Look at the animals in Figure below. How will the tadpoles change as they grow and develop into adult frogs? Complex Chemistry All living things—even the simplest life forms—have complex chemistry. Living things consist of large, complex molecules, and they also undergo many complicated chemical changes to stay alive. Complex chemistry is needed to carry out all the functions of life. Response to the Environment All living things detect changes in their environment and respond to them. What happens if you step on a rock? Nothing; the rock doesn’t respond because it isn’t alive. But what if you think you are stepping on a rock and actually step on a turtle shell? The turtle is likely to respond by moving—it may even snap at you! Keeping Things Constant All living things are able to maintain a more-or-less constant internal environment. They keep things relatively stable on the inside regardless of the conditions around them. The process of maintaining a stable internal environment is called homeostasis. Human beings, for example, maintain a stable internal body temperature. If you go outside when the air temperature is below freezing, your body doesn’t freeze. Instead, by shivering and other means, it maintains a stable internal temperature. http://www.saburchill.com/questions/lanlt001.html
• #6: All forms of life are built of cells. A cell is the basic unit of the structure and function of living things. Living things may appear very different from one another on the outside, but their cells are very similar. Unicellular Organisms. Unicellular organisms are those that contain just one single cell. Their body is made up of just one single cell. E.g. - Amoeba, Paramecium. The oldest forms of life are the unicellular organisms and they existed 3.8 billion years ago. Bacteria, Amoeba, protozia, viruses, diatoms are the five different types of unicellular organisms. This single cell regulates the various functions of the body. Unicellular organisms are invisible to the naked eye. Unicellular organisms vary in size.        The smallest bacteria measuring only a third of a micron (300 nanometers) across, ranging up to  20 cm (8 in) across. They can be viewed under a microscope only. Unicellular Organisms were the first forms of life that developed on earth. These organisms usually have cilia,flagella or pseudopodia that helps them in locomotion. They have a simple body anatomy with the most basic structures. They reproduce both sexually and asexually. They get their food by means of a process called phagocytosis where they engulf the food particles and store them in vacuoles present in them. Multicellular Organisms.                          Multicellular organisms are those living organisms that are made up of more than one cell. Their body contains many cells hence the name multicellular. Eg - Human Beings. In multicellular organisms all the cells coordinate with each other in order to regulate the various functions of the body. Multicellular organisms are visible to the naked eye unlike unicellular organisms. Because the first multicellular organisms that existed lacked hard body parts, there are no fossil records for them. There are many theories explaining the evolution of multicellularity;  1.Symbiotic Theory - This states that  first multicellular organisms arose from symbiosis of different species of single celled organisms, each with different functions. 2. Cellularization Theory - This theory states that a unicellular organism could have developed membrane boundaries/partitions around each of its nuclei,thus giving rise to multicellularity.  3. Colonial Theory -This theory states that the symbiosis of many organisms of the same species led to a multicellular organism.  Multicellular Organisms reproduce by means of sexual reproduction. Multicellular Organisms have a complex anatomy because of the various cell organelles that control the functions of the organism. Since there are more than one cell in their body, they are classified into germ cells that are the reproductive cells and somatic cells that help in body growth by cell division. Multicellular organisms have a very well coordinated cell division process in order to prevent abnormal cell division and growth.The different cells in a multicellular organism may be the Nerve Cells, Skin cells, Cardiac cells, Epithelial cells, Connective Tissue Cells,Blood Cells,Bone Cells, Muscle Cells etc.Each of these cells have their own specific functions which helps in the overall functioning of the body.
• #7: sexual reproduction -DNA from two different parentsasexual reproduction - single parent (cloning, budding) All living things are capable of reproduction. Reproduction is the process by which living things give rise to offspring. Reproducing may be as simple as a single cell dividing to form two daughter cells. Generally, however, it is much more complicated. Nonetheless, whether a living thing is a huge whale or a microscopic bacterium, it is capable of reproduction.
• #8: The Gene Theory The gene theory is the idea that the characteristics of living things are controlled by genes, which are passed from parents to their offspring. Genes are located on larger structures, called chromosomes, that are found inside every cell. Chromosomes, in turn, contain large molecules known as DNA (deoxyribonucleic acid). Molecules of DNA are encoded with instructions that tell cells what to do. Genetic Code - directions for inheritance (DNA)
• #9: Growth – getting larger Development – changing shape and structure Differentiation – cells look different and perform different functions
• #10: Differentiation – cells look different and perform different functions
• #11: Obtain and use energymetabolism - chemical reactions through which an organism builds up or breaks down materials. plants - photosynthesis Animals - eating
• #12: All living things detect changes in their environment and respond to them. What happens if you step on a rock? Nothing; the rock doesn’t respond because it isn’t alive. But what if you think you are stepping on a rock and actually step on a turtle shell? The turtle is likely to respond by moving—it may even snap at you! stimulus - a signal to which we respond response - a reaction to a stimulus
• #13: Keeping Things Constant All living things are able to maintain a more-or-less constant internal environment. They keep things relatively stable on the inside regardless of the conditions around them. The process of maintaining a stable internal environment is called homeostasis. Human beings, for example, maintain a stable internal body temperature. If you go outside when the air temperature is below freezing, your body doesn’t freeze. Instead, by shivering and other means, it maintains a stable internal temperature. Homeostasis, or keeping things constant, is not just a characteristic of living things. It also applies to nature as a whole. Consider the concentration of oxygen in Earth’s atmosphere. Oxygen makes up 21% of the atmosphere, and this concentration is fairly constant. What keeps the concentration of oxygen constant? The answer is living things. Most living things need oxygen to survive, and when they breathe, they remove oxygen from the atmosphere. On the other hand, many living things, including plants, give off oxygen when they make food, and this adds oxygen to the atmosphere. The concentration of oxygen in the atmosphere is maintained mainly by the balance between these two processes. http://www.youtube.com/watch?v=DFyt7FJn-UM.
• #14: 8) Evolution – Change over time Evolution is a change in the characteristics of living things over time. Evolution occurs by a process called natural selection. In natural selection, some living things produce more offspring than others, so they pass more genes to the next generation than others do. Over many generations, this can lead to major changes in the characteristics of living things. Evolution explains how living things are changing today and how modern living things have descended from ancient life forms that no longer exist on Earth. As living things evolve, they generally become better suited for their environment. This is because they evolve adaptations. An adaptation is a characteristic that helps a living thing survive and reproduce in a given environment. Look at the mole in Figure below. It has tentacles around its nose that it uses to sense things by touch. The mole lives underground in the soil where it is always dark. However, by using its touch organ, it can detect even tiny food items in the soil in total darkness. The touch organ is an adaptation because it helps the mole survive in its dark, underground environment.
• #15: Interdependence of Living Things All living things depend on their environment to supply them with what they need, including food, water, and shelter. Their environment consists of physical factors—such as soil, air, and temperature—and also of other organisms. An organism is an individual living thing. Many living things interact with other organisms in their environment. In fact, they may need other organisms in order to survive. For example, living things that cannot make their own food must eat other organisms for food. Other interactions between living things include symbiosis and competition.
• #16: Zoologists - animals Botanist - plantsPaleontologist - ancient life Cytologist - cells
• #17: Cell: basic unit of all living things Tissue: group of cells of the same kind Organ: structure composed of one or more types of tissues Organ system: group of organs that work together to do a certain job Organism: individual living thing that may be made up of one or more organ systems An individual mouse is made up of several organ systems. The system shown here is the digestive system, which breaks down food to a form that cells can use. One of the organs of the digestive system is the stomach. The stomach, in turn, consists of different types of tissues. Each type of tissue is made up of cells of the same type.
• #18: Organisms of the same species that live in the same area make up a population. For example, all of the goldfish living in the same area make up a goldfish population. All of the populations that live in the same area make up a community. The community that includes the goldfish population also includes the populations of other fish, coral and other organisms. An ecosystem consists of all the living things in a given area, together with the nonliving environment. The nonliving environment includes water, sunlight, and other physical factors. A group of similar ecosystems with the same general type of physical environment is called a biome. The biosphere is the part of Earth where all life exists, including all the land, water, and air where living things can be found. The biosphere consists of many different biomes.
• #19: Life on Earth is very diverse. The diversity of living things is called biodiversity. A measure of Earth’s biodiversity is the number of different species of organisms that live on Earth. At least 10 million different species live on Earth today. They are commonly grouped into six different kingdoms. Examples of organisms within each kingdom are shown in the picture on this slide