Chapter 1 Introduction: Themes in the Study of Life

Biology: Scientific study of life Bio- = life The phenomenon we call life defies a simple, one-sentence definition

Properties of Life (b) Evolutionary adaptation (a) Order (c) Response to the environment (a) Order (d) Regulation (g) Reproduction (f) Growth and development (b) Evolutionary adaptation (e) Energy processing Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Themes of Biology Identifiable common themes Makes study of complex subject more manageable Pay attention as we move through semester We will see evidence of themes many times

Theme: Hierarchy of Life Biological systems are much more than the sum of their parts Emergent properties New properties emerge with each step upward in the hierarchy of biological order Reductionism Involves reducing complex systems to simpler components that are more manageable to study

6 6.) Organs and organ systems Hierarchy of Life From atoms to organisms Cell 4.) Cells 6 6.) Organs and organ systems 7 5.) Tissues 3.) Organelles 50 µm 10 µm 1 µm 1.) Atoms 2.) Molecules Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Theme: Organisms Interact with Other Organisms and their Environment Organisms exist in constant interaction with other living organisms and the physical world Nutrients and other vital materials are cycled through living organisms, into the environment and back again Global climate change is just one of many examples of this interaction

Theme: Energy Transfer and Transformation Activities of life Require organisms to perform work, which depends on an energy source The exchange of energy between an organism and its surroundings Often involves the transformation of one form of energy to another

Energy flows through an ecosystem Energy Conversion Energy flows through an ecosystem Usually entering as sunlight and exiting as heat Producers (plants and other photosynthetic organisms) Consumers (including animals) Sunlight Chemical energy Heat Ecosystem Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Theme: Structure and Function Things are constructed based on their function Ex. Wheels are round so they can roll so they can move a vehicle Can you think of some biological examples of structure and function?

Theme: The Cell The cell is the lowest level of organization that can perform all activities required for life All living organisms are made of cells

Types of Cells All cells share certain characteristics They are all enclosed by a membrane They all use DNA as genetic information There are two main forms of cells Prokaryotic: No membrane bound nucleus Eukaryotic: Does have membrane bound nucleus

Prokaryotic cells vs. Eukaryotic cells Membrane Cytoplasm Organelles Nucleus (contains DNA) 1 µm PROKARYOTIC CELL DNA (no nucleus) Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Theme: The Cell’s Heritable Information Cells contain chromosomes made partly of DNA, the substance of genes Which program the cell’s production of proteins and transmit information from parents to offspring Egg cell Sperm cell Nuclei containing DNA Fertilized egg with DNA from both parents Embyro’s cells with copies of inherited DNA Offspring with traits inherited from Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Theme: Evolution Main theme of biology Evolution explains diversity and unity of all living organisms on our planet

Organization: Three Domains of Life At the highest level, life is classified into three domains Bacteria Archaea Eukarya

Organization: Three Domains of Life Domain Bacteria and Domain Archaea Consist of prokaryotes Domain Eukarya, the eukaryotes, includes Multiple kingdoms: Protista Kingdom Plantae Kingdom Animalia Kingdom Fungi