Biolgy : is the sience of life and living organisms , including their structure , function grooth , origin ,evolution ,distribution and taxonomy.
It includes botany and zoology
Although living things are divers , they share certain characteristics in common ( Fig.1.1)
1-living things are organized ( Fig1.2)
The smallest unit of living organsims is the cell
2-living things acquire materials and energy : human and other animals acquire materials and energy when they eat food
Foot provides nutrient molecules which are used as building blocks or for energy.
Metaboism : is all the chemical reactions that occur in a cell
3- Living things respond to external stimuli : All living things are able to respond t stimui in the exernal enviroment . For example :living things respond to change in light,heat,sound and chemical ad mechanical contact. To detect stimuli,organism have means for receiving informations such as eyes,ears and taste buds.
4-living things repoduce and develop.
5- Living things adapt and evolve
Adaptation : are modifications that make organism suited to its way of life in a particular enviroment
Evolution : is the process by which a species changes through time.
The process of science : The ultimate goal of science is to understand the natural world in terms of theories. Some of the unifying theories of biology are shown in the following :
Theory: concept:
Cell : All organism are composed of cells, and new cells only come from Pre-existing cells.
Homeostasis : The internal enviroment an organism stays relatively constant
Genes : organisms contain coded information that dictates their form ,function and behavior
Ecosystem : Populations of organisms interact with each other and the physical enviroment.
Evolution : All organisms have a common ancestor , but each is adapted to particular way of life.