Chapter 1 What is Biology?

Biology in Everyday Life

Warming of the Climate System From Newsweek Aug 13, 2007 Floods, Findings At least 90 percent certainty that global warming is man-made. Reducing CO2 More CO2 leads to more warming. 2006 The Electric Car 2005 Extreme Weather 2003 Heat Wave 1999 Polar Bears at Risk 1998 Fueling Debate 1997 Fire and rain 1992 Rio Treaty Cutting emissions of greenhouse gases

So then, what is biology? The science that deals with life. What is science? A process used to solve problems and understand natural events. Involves the scientific method.

Components of the scientific method Observation Questioning and exploration Forming and testing hypotheses Evaluation of new information Review by peers

A sample experiment Hypothesis: Male sex hormones produced by the testes stimulate male birds to sing. Experimental group: Male birds with testes removed at birth. Control group: Male birds subjected to a similar surgery that were allowed to develop normally with testes. Independent variable: presence or absence of testes. Dependent variable: presence of singing behavior Data: Male songbirds without testes do not exhibit singing behavior. Conclusion: Hypothesis is supported.

The science of biology The study of living things. Theoretical biology Evolutionary biology, animal behavior, biochemistry Applied biology Medicine, crop science, plant breeding, wildlife management

Levels of biological organization Biosphere — the worldwide ecosystem. Ecosystem — communities that interact with one another in a particular place. Communities — populations of different organisms interacting with each other in a particular place. Population — a group of individual organisms in a particular place. Organism — an independent living unit. Organ system — many organs that perform a particular function. Organ — many tissues that perform a particular function. Tissue — many cells that perform a particular function. Cell — simplest unit that shows characteristics of life. Molecules — specific arrangements of atoms. Atoms — the fundamental units of matter.