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Biology Notes Introduction to Life

What my Intro to Biology Study Guide Looks Like

Identify and describe the properties of life.  – Living things share some common properties. According to our online reading material the properties of life are order, sensitivity or response to stimuli, reproduction, adaption, growth and development, regulation, homeostasis, and energy processing.  These 8 characteristics characterize living things.  Life displays order through the organization of the organism.  Living things will either respond positively or negatively to stimuli.  Then, there is reproduction. which single-celled organisms are able to do by copying and duplicating its DNA. Once the information is copied it divides equally, while many multi-celled organisms produce special reproductive cells that form new individuals. DNA, which contains the genetics, are passed down to offspring after reproduction  Adaptation has to do with how a living organism “fits” into their environment and the process of natural selection allows for organisms to change accordingly to that environment.  Though adaption is not constant, whenever there are changes in the environment, the population of that environment will change to maximize their reproductive potential in accordance with those new changes. Growth and development is an obvious sign of something living and it happens based on the genes which were passed by the parents.  The regulation of all these complex processes happens constantly while that organism remains alive.  Even small organisms need a mechanism to coordinate and regulate internal functions. Homeostasis allows an organism to keep a constant internal state or “steady-state”.  A polar bear, for example, keeps homeostasis through a process called thermoregulation.  Last is energy processing.  All living organisms use a source of energy.  Energy allows for metabolic activities to happen.  Some organisms get their energy from the sun which is changed and converted into chemical energy.  Other organisms get their energy from molecules taken in.

Describe the levels of organization among living things – Organisms organize in complex ways.  We start this organization at the atomic level with the smallest unit of matter, the atom.  The atom is comprised of a nucleus that is surrounded by electrons.  Then, when 2 atoms form a chemical bond we get a molecule.  There are macromolecules (which are pretty important biologically!) which usually form by the combination of these smaller units named monomers.  DNA is an example of a macromolecule.   There are cells that aggregate macromolecules that are surrounded in membranes.  These are called organelles.  Organelles are tiny structures within cells that perform functions that are highly specialized for that cell.  Cells are fundamental for life and the smallest unit of function and structure in all living things. Viruses have no cells, which is why most do not consider viruses to be alive).  Those cells which consist of only one cell are considered prokaryotes. These cells lack nuclei as well as organelles. Multicellular cells are made up of at least 2 cells, these are called eukaryotes.  Eukaryotes do contain nuclei and organelles that are membrane-bound.  

List examples of different sub-disciplines in biology –  There are many fields of sub-disciplines within biology. Molecular biology deals with those things at the molecular level and the interaction between molecules.  Then there is microbiology which looks at how microorganisms interact with each other. Neurobiology (also referred to as neuroscience) studies the nervous system.  There is also the field of forensics that looks at the evidence left at crime scenes to figure out information on what happened.

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