Importance Of Biology: Scientific Study Of Life

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Biology – scientific study of life
Hierarchy of life
Biosophere>ecosystem>community>population>organism> organ system>organ>tissue>cell>organells>molecule>atom
Life is ordered & organized

Themes in biology
Organisms interact with the environment
Matter and energy exchange
Adapt to change living and non-living elements
Nutrients recycle while energy enters and exits (nutrient cycling – light, thermal, chemical, kinetic some heat is always lost) Structure and function are interrelated – or – form follows function
Maximize surface area for absorption or energy production.
– an organisms basic unit of structure and function
–enclosed by a membrane
– use DNA as genetic information
– lowest level that can preform all activities required for life.
Two Types of Cells
Eukaryotic – has nucleus and organelles (all other life forms)
Prokaryotic – doesn’t have nucleus or organelles (Achaea & Bacteria). Most are single celled & microscopic
Activities of all organisms based on activities of cells.
Properties of all organisms based on the structure & function of cells.
Division of cells to form new cells is the foundation for all reproduction, growth, & repair of multicellular organisms.
Contain most of the cells genetic material via DNA
Continuity of life based on passing on info.
Genes are units of inheritance – specify proteins (some RNAs)
Structure & function varies for all organisms
Inherited by offspring with controls
Substance of genes
Genes encode info necessary to build other molecules of cell (most notably protein)
Proteins mainly responsible for building & maintaining cells – enzymes speed up specific chemical reactions mainly proteins
Serves as central data base
4 subunits A T C G
Feedback mechanisms help regulate systems
Gene expression entire process by which info in a gene directs production of cellular product
Negative feedback inhibits & stabilizes
Positive feedback stimulates & destabilizes
Biology that classifies & names species into groups of increasing breadth
3 domains – Archaea, Bacteria & Eukarya
Kingdoms in Eukarya – Protists Plantae, Fungi, & Anamalia. Plantae, Fungi, & Anamalia are multicellular eykaryotes distinguished by modes of nutrition. Protists have membrane bound nucleus that bacteria lack.
Within diversity unit common genetic code, common structural features
Core theme in Biology is Evolution Decent from a common ancestor w/modification
Accounts for diversity and unity of all life
1.8 million species identified, named & growing
Total # of extant species 10-100 million
Darwin “Origin of Species by Means of Natural Selection” 1859
Darwin Observed
Individuals in populations have traits that vary
Many traits inherited
More offspring are produced than survive
Competition is inevitable
Species generally suit their environment.
Darwin inferred
Best suited individuals for environment survive
Over time more individuals of a population have the advantageous traits
Natural environment “selects” for beneficial traits.
Discovery Science
Based on observation and analysis of data.
Data – 2 types
Qualitative – descriptions
Quantative – recorded measurements
Repeat specific observations can lead to important generalizations.
Hypothesis based
Tentative answer to a well framed question.
Relies on deduction to arrive at answers.
Must be testable
Generates predictions
Must be falsifiable
Not provable
Systems Biology
Scientists attempt to model dynamic behavior of whole biological systems based on interaction of system parts

Takes up space
Has mass
Composed of subatomic particles atoms  elements  compounds
Smallest particle of an element that retains the properties of the element
Matter composed of a single type of atom – cannot be broken down to other substances by a chemical reaction
92 naturally occurring elements
25 essential to life (C, H, O, N