Bio. Chapter 1: Science of Life Biology => the study of all living things Organism => Living thing 40 million species estimated to exist 2 million identified/named Only a few thousand studied !!!! Too huge to view overall, need to narrow down to several THEMES that unify all of biology.

Science  From the Latin verb ‘scire’ meaning “to know”  Science is a process of asking questions and looking for explanations. It is a way of knowing.  Chemistry, Physics, Earth Science, Ecology, Environmental science, anatomy, physiology, microbiology…..

Themes of Biology 1. Cell structure and function 2. Stability and Homeostasis 3. Reproduction and Inheritance 4. Evolution 5. Interdependence of organisms 6. Matter, energy and organization We can study any biology idea (tree, frog, forest) from the level of each theme.

Cell Structure and Function The cell is the structural and functional basis (unit) of all life. Unicellular organisms  those having only one cell; bacteria and algae and fungi Multicellular organisms  those have “many” cells; humans, trees, etc. Differentiation  many kinds of cells within an organism….skin, nerve, muscle

Stability and Homeostasis Homeostasis  internal conditions stay steady while external conditions may fluctuate. Human body 98.6 F or 37 C Blood pressure, blood sugar, heart rate… Single celled and multicelled organisms must regulate their internal situations.

Reproduction and Inheritance Reproduce  transmit hereditary information to offspring. Asexual reproduction  one DNA source like bacteria that divide into two cells Sexual reproduction  two DNA sources egg + sperm or pollen = embryo DNA  chemical that stores information Gene  region on DNA for a trait (protein)

Evolution Populations of organisms change, or evolve, over generations. Natural Selection is the driving force behind evolution as it allows favorable traits to be represented in the population Lots more on this unit later… just keep in mind that organisms are not static.

Interdependence of Organisms Ecology  the branch of biology that studies the interactions of organisms with other living organisms and with their physical environments. Organisms, populations, communities, ecosystems, biomes…..

Matter, Energy and Organization Highly organized collections of cells Require lots of energy input (Metabolism) Photosynthesis, which requires the sun, is the energy source for all life on Earth Autotrophs  make own fuel (plants) Heterotrophs  require pre-made fuel, everything that’s not a plant (us)