B Bacillus. Rod-shape bacterium. Big bang. Scientific theor y that proposes an explanation of the origin of the Universe and its expansion from a big explosion 14 billion years ago. Bilateral . Type of symmetr y presented in animals that divides the body in two identical sides. Binar y fission. An asexually type of reproduction in which a cell is divided in two daughter cells, identical to the mother cell . This is common in bacteria and some protozoa . Biocenosis. Also known as community. It consists of all the populations of living things in an ecosystem. From the Greek bios: life and koinós: common . Biodiversity. All the living things that live in a specific place. The variety of species is consequence of evolution and adaptation presented by living things. Biofuel . An efficient and less polluting fuel extracted from vegetables. Biosphere. It is made up of all the living things on Earth . From the Greek bios: life and sphâira: sphere. Biotope. All the non-biological components of an ecosystem like rocks, water and air and all the physical variables that can be measured: temperature, light, humidity, etc. From the Greek bios: life and tópos: place. Bitominous coal . Sedimentar y rock formed from the remains of living things buried millions of years ago. It is a fossil fuel predecessor of the anthracite, coal that has the highest energy content. Bivalves. Group of invertebrate with a shell consisting in two hinged valves connected by a ligament. For example, clams, mussels and cockleshell . From the latin bi: two and valva: door. Budding. An asexually type of reproduction that produces a protusion or bud capable of developing into a new organism. Bulbs. These are underground stems inside fleshy leaves. The leaves store nutrients. Each bulb can produce a new plant. For example, the onion . > W rite a short text in which you include three terms defined in these two pages. > G ive an example of a natural adaptation in animals, and another in plants. > L ooking at the definition of arthropods, would you know the meaning of apod? > H ow many animal groups are in these two pages? Classify them into vertebrates and invertebrates. 25
RkJQdWJsaXNoZXIy