Introducing
Your new presentation assistant.
Refine, enhance, and tailor your content, source relevant images, and edit visuals quicker than ever before.
Trending searches
All living things on Earth are either unicellular (they are made of one cell), or multicellular (they are made of many cells). A cell is a highly organized, tiny structure with a thin covering called a membrane and is the smallest unit able to carry out all life functions. The sturcture of cells in all organisms is pretty similar. A paramecium is a single-celled organism. A human is a multicellular organism. A human body has more than 100 trillion cells.
All living things are able to reproduce. Reproduction is the process by which organisms make more of their own kind from one generation to the next. Some bacteria divide into offspring cells every 15 minutes. Bristlecone pine trees that are 5,000 years old still produce seedlings. Since no organisms live forever, reproduction is essential.
Unifying Themes
All living organisms carry out numerous different chemical reactions so they can obtain and use energy to run the processess of life. All living organsims use energy to grow, move, and process information. Without energy, life soon ceases. Metabolism is the sum of all the chemical reactions carried out in an organism.
In the study of Biology, a number of broad themes emerge that both unify living things and aid in explaining Biology as a science. Biology is the study of life.
All living things must be able to maintain a stable internal environment to work the right way. When organisms respond to changes in their external environment, their internal environment changes to match. The maintenance of this stable internal environment is called homeostasis. If an organism is unable to maintain this stable internal environment, it could get sick and die.
All living things are able to pass on traits to their offspring through genes. A gene is the basic unit of heredity. Heredity is the reason why some children sometimes tend to resemble their parents. Sometimes, damage can cause genes to change. This is called a mutation. The majority of mutations are harmful, but sometimes they can aid in survival.
Mutations for the blood protein hemoglobin, which carries oxygen to the cells of the body, has a harmful effect but it also has a positive effect. The harmful effect is that it can result in sickle cell anemia. This is a disease in which the defective form of hemoglobin causes many red blood cells to bend into a sickled shape which reduces the oxygen-carrying capability of that cell. Mutations in sex cells are passed from one generation to the next. Mutations in body cells are not, but they can disrupt control of cell reproduction and result in cancer.
The great diversity of life on Earth is the result of a long history of change. Change in the inherited characteristics of species over generations is called evolution. A species is a group of gentically similar organisms that can produce fertile offspring. Individuals are similar, but not identical. The individuals with genetic traits that better enable them to meet nature's challenges tend to survive and reproduce in greater numbers, which causes these favorbale traits to become more common. A nineteenth-century British naturalist, Charles Darwin, used the term "natural selection" to describe these processes.
Darwin's theory in biological community live and interact with the other organisms. Ecology is the branch of Biology that studies these interactions of organisms with each other and the nonliving part of their environment. Organisms are dependent on one another and their environment (this is called interdependent). Interdependence within biological communities is a result of a long history of evolutionary changes. This complex web of interactions is dependent on the proper functioning of all its members... even its microscopic ones.