Biological Themes Chapter 1

Biology The study of life. Includes the study of microscopic structure of single cells, study of the global interactions of organisms, & life history of these organisms.

Biological Themes Cell Structure & Function Cell Structure & Function Stability & Homeostasis Stability & Homeostasis Reproduction & Inheritance Reproduction & Inheritance Evolution Evolution Interdependence of Organisms Interdependence of Organisms Matter, Energy, & Organization Matter, Energy, & Organization

Cell Structure & Function The cell is the basic unit of life. The cell is the basic unit of life. Some organisms are Some organisms are –Unicellular –Multicellular –Differentiation: cells becoming different from one another as they multiply.

Stability & Homeostasis Homeostasis – Stable level of internal conditions found in all living things. Homeostasis – Stable level of internal conditions found in all living things. –Biological balance a cell maintains with its environment.

Reproduction & Inheritance Reproduction: the transmission of hereditary information from parents to offspring. –S–S–S–Sexual reproduction: two parents, genetic material is combined. –A–A–A–Asexual reproduction: one parent, no combining of genetic material.

Evolution Evolution: Change over a long period of time. Evolution: Change over a long period of time. Natural Selection Natural Selection –Survival of the fittest.

Interdependence of Organisms Ecology: Study of organisms and with one another and their environment. Ecology: Study of organisms and with one another and their environment. Ecosystems: Environmental communities. Ecosystems: Environmental communities.

Matter, Energy, & Organization Living things have highly organized structures that must be maintained by a constant supply of energy. Living things have highly organized structures that must be maintained by a constant supply of energy. –Photosynthesis: the capture of energy from the sun and conversion into food. the capture of energy from the sun and conversion into food. –Autotrophs: Make their own food, plants. Make their own food, plants. –Hetertrophs: Don’t make their own food, animals. Don’t make their own food, animals.

Characteristics of Life Cells Cells Organization Organization Energy Use Energy Use Homeostasis Homeostasis Growth Growth Reproduction Reproduction

Life Processes Certain activities that make life possible. Certain activities that make life possible. –Nutrition –Transport –Respiration (breakdown of food for energy) –Synthesis & Assimilation –Growth & Reproduction –Excretion –Regulation

Scientific Method Observing/Asking a Question Observing/Asking a Question Hypothesizing Hypothesizing Experimenting Experimenting Collecting and Analyzing Data Collecting and Analyzing Data Drawing Conclusions/ Communicating Results Drawing Conclusions/ Communicating Results

Variables & Controls Whenever possible, a hypothesis should be tested by an experiment in which ONE variable is changed at a time. Whenever possible, a hypothesis should be tested by an experiment in which ONE variable is changed at a time.

Variables & Controls cont……… Independent Variable: MANIPULATED; The variable that is changed. Independent Variable: MANIPULATED; The variable that is changed. Dependent Variable: RESPONDING; the variable that changes in response to the manipulated variable. Dependent Variable: RESPONDING; the variable that changes in response to the manipulated variable. Controlled Variables: The variables that are kept constant. Controlled Variables: The variables that are kept constant.

Quantitative vs Qualitative Quantitative: Numerical value – –Quant…quanitity…number Qualitative: Value of words Examples: – –Amount of rainfall in each state in the US

Graphs Bar: – –Qualitative value and quantitative value Line: – –Quantitative value and quantitative value Pie: – –Percent of a whole

Microscope & Measurement Compound Light Microscope Compound Light Microscope Magnification Magnification –increase of the image’s apparent size Resolution Resolution – the power to show details clearly

Electron Microscope A beam of electrons produces an enlarged image of the specimen. A beam of electrons produces an enlarged image of the specimen. –TEM: transmission electron microscope Can view the internal structure of an organism. Can view the internal structure of an organism. Magnifies up to 200,000 times. Magnifies up to 200,000 times. –SEM: scanning electron microscope View the surface of an object View the surface of an object Magnifies up to 100,000 times. Magnifies up to 100,000 times.

TEM

Images under TEM LungSpinach chloroplast LungSpinach chloroplast

Rat NerveMouse kidney Rat NerveMouse kidney

Sperm and egg Sperm and egg

SEM

Under an SEM PollenLung PollenLung

Leaf vein Staple through paper Leaf vein Staple through paper

Toilet paperHypodermic needle Toilet paperHypodermic needle

Mascara brush with flakes of skin and bacteria Mascara brush with flakes of skin and bacteria

Sperm and egg Sperm and egg

Disadvantages – Electron Microscopes Very expensive Very expensive Cannot be used to view a living specimen Cannot be used to view a living specimen Can be large Can be large

Other Lab Techniques Cell culture – growth of cells in lab. Cell culture – growth of cells in lab. Cell Fractionation – used to release components of cells. Cell Fractionation – used to release components of cells. Centrifugation – separation of cell parts by spinning Centrifugation – separation of cell parts by spinning Chromatography – separation of components; uses special paper, etc. Chromatography – separation of components; uses special paper, etc. Electrophoresis – separation of components based on electrical charge & size. Electrophoresis – separation of components based on electrical charge & size.