Studying Life What are some of the characteristics of living things? How can life be studied at different levels? Chapter 1 Section 3 Pages 16 - 22 Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Characteristics of Living Things are made of cells reproduce are based on a universal genetic code grow and develop obtain and use materials and energy respond to their environment maintain a stable internal environment taken as a group, change over time (evolve) Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Made of Cells Cells – smallest unit of an organisms that possesses all characteristics of life Unicellular composed of only one cell Multicellular composed of many cells Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Reproduction Reproduction – process of making more of own kind Sexual – two special cells (gametes) two parent individuals new individual different from either parent individual Asexual – No special cells one parent individual new individual identical to parent individual Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Based on a Genetic Code Genetic Code – determines inherited traits DNA or RNA – carries inherited traits in all organisms on Earth Mechanisms of control are the same in all organisms on Earth Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Growth and Development All living things grow during their lifetime Unicellular increase in size (growth) Multicellular increase in size increase number of cells cells take on different roles (differentiation) may have different forms (development) Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Need for Materials and Energy Metabolism – combination of chemical reactions needed to stay alive Anabolism (Synthesis) –build up materials. Catabolism (Decomposition) –break down materials to release energy to get substances needed to build up. Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Response to the Environment Stimulus – a signal to which an organism responds, usually involves a change. External Stimuli – changes outside light temperature sounds. Internal Stimuli – changes inside pain chemical levels pressure. Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Maintaining Internal Balance Homeostasis – internal conditions remain constant when external conditions change. Thermostat – controls house temperature Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Evolution The very slow change of groups of organisms over time Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Branches of Biology Anatomy (anatomist) Biochemistry (biochemist) Botany (botanist) Cytology (cytologist) Ecology (ecologist) Genetics (geneticist) Paleontology (paleontologist) Study of body structure Study chemicals of life Study of plants Study of cells Study of environment Study of heredity Study of ancient life Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Levels of Biological Organization Biosphere Ecosystem Community Population Organism System Organ Tissue Cell Organelle Molecule Life found on Earth All life and non living in area All life in area All life of one species in area Individual life Organs work together Tissues work together Cells work together Structural & functional unit of life Cell part with function Chemical with function Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Tools and Procedures What measurement system do most scientists use? How are light microscopes and electron microscopes similar? How are light microscopes and electron microscopes different? Chapter 1 Section 4 Pages 24 - 28 Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Common Measurement System Metric System (SI System) Decimal system (based on multiples of 10) Units increase in 10’s to measure larger deka- 10x hecto- 100x kilo- 1,000x mega- 1,000,000x Units decrease in 10’s to measure smaller deci- 1/10x centi- 1/100x milli- 1/1,000x micro- 1/1,000,000x nano- 1/1,000,000,000x Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Common Metric Units Length Volume Time Mass Temperature meter liter second Mass gram Temperature degrees Celsius Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Microscope produce magnified images of structures too small to see with unaided eye. Light Microscope focus visible light Electron Microscope focus beams of electrons Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Types of Electron Microscopes Transmission (TEM) beam through a thin sample of specimen show inside details Scanning (SEM) beam back and forth over the surface forms 3-D image Updated July 5, 2004 Created by C. Ippolito July 5, 2004

Lab Techniques Cell Cultures Cell Fractionation grow groups of cells from a single cell cell responses cell interactions Cell Fractionation a.k.a ultracentrifugation separate cell parts function of organelle Updated July 5, 2004 Created by C. Ippolito July 5, 2004

More Lab Techniques Chromatography Electrophoresis separates chemicals based on solubility Electrophoresis separates chemicals based on charge/size DNA fingerprinting Updated July 5, 2004 Created by C. Ippolito July 5, 2004