Introduction to Biology Biology The Study of Life

Introduction to Biology

Biology – The Study of Life • Life arose more than 3. 5 billion years ago • First organisms (living things) were single celled • Organisms changed over time (evolved)

Characteristics of Life (1) Order (2) Regulation (5) Response to the environment (3) Growth and development (4) Energy processing (6) Reproduction (7) Evolutionary adaptation

The Unity of Life: All forms of life have common features 1. Complex Organization/Order 2. Regulate internally 3. Growth and development 4. Energy processing 5. Contain DNA 6. Respond to the environment 7. Reproduce 8. Adapt 9. Evolve/Change Copyright © 2009 Pearson Education, Inc.

Themes of Biology n Seven Themes of Biology 1. Cellular Organization 2. Reproduction 3. Metabolism 4. Homeostasis 5. Heredity 6. Evolution 7. Interdependence

Biology Theme Descriptions 1. Cell Structure and Function • Cells are basic unit of life • All organisms are composed of and arise from cells

Organization • Life is organized at both the molecular and cellular levels

• In multicellular organisms, cells and groups of cells (tissues) are organized by their function Cells tissues Cells Tissues organs Tissues Organs body systems Body Systems ORGANISM 8

2. Homeostasis – maintaining an internal balance despite changes in the external environment. § Organisms must maintain very stable internal conditions to sustain life § Temperature, blood pressure, blood p. H

3. Heredity& Reproduction § Organisms must reproduce in order to perpetuate the species. § Organisms transmit genetic information to their offspring -Heredity

4. Reproduction (Growth) § Grow occurs as the result of cell division and cell enlargement § Cell division is the formation of two cells from a preexisting cell § New cells enlarge as they mature

5. Metabolism § ALL energy comes from the SUN (directly or indirectly) § Photosynthesis – process plants use to convert solar energy into chemical

Metabolism -Sum of all chemical reactions Cellular respiration-Breakdown of glucose to generate energy § Photosynthetic organisms -Autotrophs (producers) plants, some bacteria § Heterotrophs- (consumers) animals

6. Interdependence of Organisms § Interaction of organisms with one another and with their environment § Symbiotic relationships § Predator/prey relationships § Food Webs- passage of energy through trophic levels

Interdependence Continued. . § Life requires interactions between biotic and abiotic components § Organisms respond to stimuli in the external environment

7. Evolution § Evolve means to change. § Change occurs as the environment changes selecting favorable characteristics. § These favorable characteristics are known as adaptations § natural selection“survival of the fittest” 16

Natural Selection § Natural selection is the driving force in evolution § Organisms that have favorable traits are more likely to survive and reproduce passing these traits on to future generations 17