Ch 1-A View of Life

Ch 1-A View of Life - Ch 1 - A VIEW OF LIFE Biology...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Ch 1 - A VIEW OF LIFE Biology Characteristics of Organisms composed of cells-Cell Theory growth & development metabolism-homeostasis response - movement, locomotion reproduction-asexual, sexual Biological Organization Information Transfer Evolution/Natural Selection Energy Flow Scientific Method Observation Problem/Question Hypothesis/Prediction Experiment (variables, control) Conclusion Biology is the science/study of life - Why study life? Life forms are called organisms and they share certain characteristics. CHARACTERISTICS OF LIFE 1 Organisms are composed (organized) of cells and cell products ( Cell Theory) and arise from pre-exiting cells (no spontaneous generation) – cells are enclosed by a membrane (prokaryotic, eukaryotic) and may have membrane enclosed organelles (eukaryotic) Organisms can be either: unicellular - bacteria, most protists multicellular - most fungi, plants, animals Cellular components produce extracellular components such as hair, nails, etc. Infectious particles – ie virus are not cellular and must use host cells which they parasitize/infect-are they alive? 2. Grow - cells increase in number or size and usually develop ( change ) Growth may be for a definite period or continue indefinitely and function continues during growth Many begin as an egg and grow and develop specialized structures and body forms 3. Metabolize - use chemical activity for growth, repair, & reproduction - all these must be kept in homeostasis ("same" state) - balanced internal environment-changes are maintained within a range . Human cells require nutrients in the form of glucose. Glucose availability is balanced by storing excess glucose in the liver when levels are high and converting it back into glucose for the blood stream when glucose levels are low. 4. Respond to stimuli (changes) - physical (light, temperature, pressure, sound), chemical (pH, different concentrations) An organism responds with electrical or chemical signals - may cause movement Move - all cell material is constantly moving (cytoplasmic streaming) (cyto = cell, plasm = material) Most animals exhibit obvious body movement, even plants move: toward light, the Venus Flytrap even closes on food Locomotion (movement from place to place) is accomplished by various means: amoeboid/ameboid) motion - streaming cytoplasm pushes cell along cilium/cilia (hair-like), flagellum/flagella (whip-like) cell extensions move the cell or the medium around the cell muscular movement
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 3

Ch 1-A View of Life - Ch 1 - A VIEW OF LIFE Biology...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online