Chpt 1 The Science of Life

The Study of Life The first life form probably arose on Earth more than 3.5 billion years ago. This organism was probably a single cell and over time changed. Biology studies these organisms and common themes occur throughout: Cell structure and function Stability and homeostasis Reproduction and inheritance Evolution Interdependence of organisms Matter, energy and organization

Themes of Biology 1. Cell Structure and Function Cells = smallest unit of life Unicellular vs. Multicellular Cells are small but highly organized Cells in a multicellular organisms have undergone differentiation.

Themes of Biology 2. Stability and Homeostasis All living things want to have and maintain very stable internal conditions.

Themes of Biology 3. Reproduction and Inheritance All organisms produce new organisms that are like themselves. This is due to DNA. This information is passed through either sexual or asexual reproduction.

Themes of Biology 4. Evolution Populations change over time. Scientists suggest natural selection drives evolution. Ability to attain resources can affect individuals within a species. “descent with modification”

Themes of Biology 5. Interdependence of Organisms To truly understand biology interactions must be studied. This is called ecology.

Themes of Biology 6. Matter, Energy and Organization Living things must be maintained with a constant supply of energy. Almost all energy for life comes from the sun. (photosynthesis) Organisms can obtain energy in a couple of different ways: Autotrophs heterotrophs

Biology is the study of life! What are the characteristics of something that is “alive”? Does it have to move? Does it have to have lungs? Does it have to have sunlight? Does it have to have a mouth? Is this alive?

Slime molds Are actually alive! Use spores to reproduce and decompose tiny microorganisms

Bornean flat-headed frog – no lungs; breathes through skin Lichen – doesn’t move No sunlight No mouth

Characteristics of Life Cells Organization Energy Use Homeostasis Growth Reproduction

1-3 Scientific Method

1-4 Microscopes One of the most widely used tools in biology Produces an enlarged image of an object Types: Compound Stereo Electron (TEM and SEM)

Measurement Base Units Describe length, mass, time and other quantities Derived units can be used to measure surface area or velocity and many other things Dimensional Analysis