The Science of life Chapter 1 Biology II

Vocabulary- The Science of Life- 22 words Biology development Organization reproduction Cell gene Unicellular domain Multicellular kingdom Organ ecology Tissue ecosystem Organelle evolution Biological molecule natural selection Homeostasis adaptation Metabolism Cell division

A. The World of Biology Biology: the study of life Biologists study many different kinds of life from very tiny to very large Biologists investigate subjects that affect you and the way you live

4. Characteristics of Life All living things share seven characteristics 1. Organization and Cells a. Organization: the high degree of order within an organism’s internal and external parts and in its interactions with the living world

b. Cell: the smallest unit that can perform all life’s processes 1. unicellular: made up of one cell 2. multicellular: made up of multiple cells Organs: structures that carry out specialized jobs within an organ system Tissues: groups of cells that have similar abilities and that allow the organ to function Organelles: within each cell, tiny structures that carry out functions necessary for the cell to stay alive Biological molecules: the chemical compounds that provide physical structure and function

2. Response to Stimuli- must be able to respond and react to changes to stay alive Homeostasis- the maintenance of a stable level of internal conditions even though environmental conditions are constantly changing Metabolism- the sum of all the chemical reactions that take in and transform energy and materials from the environment

5. Growth and Development Cell division: the formation of two new cells from an existing cell Development: the process by which an organism becomes a mature adult

Reproduction: the production of new organisms Essential for the continuation of a species Gene: a short segment of DNA that contains the instructions for a single trait of an organism Sexual reproduction(resulting offspring not identical to parents)/asexual reproduction (resulting offspring identical to original) 6. Reproduction

7. Change through time- populations of living organisms evolve or change through time

B. Themes in Biology Diversity and Unity of Life a. All living things share certain sets of genes, inherited from a single common ancestor b. Different species possess certain sets of genes unique to them

c. Three domains of life domain: major subdivisions of all organisms Bacteria, Archea, and Eukarya Domains are divided into the following six kingdoms: a. Domain Bacteria- Kingdom Bacteria b. Domain Archaea- Kingdom Archaea c. Domain Eukarya- Kingdoms Protista, Fungi, Plantae, and Animalia

2. Interdependence of Organisms Ecology: the branch of biology that studies organisms interacting with each other and with the environment Ecosystems: communities of living species and their physical environment all organisms are interdependent upon one another and their environment for survival

3. Evolution of Life Evolution (descent with modification): the process in which the inherited characteristics within populations change over generations, with giving rise to new species Evolution helps construct the “tree of life” Natural selection: organisms with certain favorable traits are better able to survive and reproduce successfully than organisms that lack these traits

d. Adaptations: traits that improve an individual’s ability to survive and reproduce