Biology Chapter 1 Notes

The Study of Life Organism – living thing containing organs(organelles in some cases) Biology – the science of life

Themes of Biology Cell structure and function Stability and Homeostasis Reproduction and inheritance Evolution Interdependence of organisms Matter, energy, and organization

Cell Structure and Function Unicellular organisms – organisms with only 1 cell Multicellular organisms – organisms composed of more than 1 cell Differentiation – becoming different as multiplication occurs and specializing.

Stability and Homeostasis Homeostasis – stable level of internal conditions. –Found in all living things –“stability” is actions that drive toward homeostasis. Example: thirst/drinking water

Reproduction and Inheritance Reproduction – all organisms produce new organisms like themselves. –Hereditary information is passed on from parent to offspring. Large molecule = DNA(deoxyribonucleic acid) –Cytocine, adenine, thymine, guanine –A with T, C with G

Reproduction and Inheritance, cont. Gene – short segment of DNA that contains the instructions for the development of a single trait of an organism. ***(new notes) Sexual reproduction – hereditary information is combined 1 of 2 ways parts from a single organism (flower) 2. 1 part from two organisms of the same species.

Reproduction and Inheritance, cont.2 Asexual reproduction – hereditary information from different organisms isn’t combined. –Example : bacterium splitting in 2. Contains identical copies of itself = clone.

Evolution Change over generations Explains how organisms alive today are related to those that lived in the past Provides a basis for exploring relationships among different groups of living organisms. –Natural selection – most important driving force in evolution. Organisms that have certain favorable traits are better able to successfully reproduce than organisms that lack these traits.

Interdependence of Organisms Ecology – interaction of organisms with one another and with their environment. –Example : populations of predators/prey Ecosystems = environmental communities.

Matter, Energy, and Organization Photosynthesis – changing energy from the sun into energy plants can use Autotrophs – make their own food. Heterotrophs – must take in food to meet energy needs.