E XPLORING L IFE Chapter 1

W HAT IS THE S CIENCE OF B IOLOGY ? Biology is the study of life Scientific inquiry is key Asking questions about living organisms and deriving scientifically supported answers What makes a living organism? Seven characteristics are used by scientists to define life Neither inclusive or exclusive LIMITATIONS EXIST

L IFE ’ S C OMMON F EATURES LIMITATIONS EXIST

H IERARCHICAL C LASSIFICATION OF L IFE Biosphere – all regions of Earth the support life Ecosystems – all living and non-living organisms in an area Communities – all species living in one area Populations – individuals of a species in a specific area Multi-celled organisms – each living individual in an area Organ systems – 2+ organs interacting to enhance survival Organs – body part with 2+ tissues performing common tasks Tissues – cells working together for a specialized activity Cells – smallest unit able to demonstrate characteristics of life Organelles – internal compartments of cells for specialized reactions Molecules – 2 or more atoms bonded together

T HE W HOLE IS M ORE THAN THE S UM OF ITS P ARTS Emergent properties Novel properties emerge with each step up the hierarchy (most exclusive to most inclusive) Reductionism Reducing complex systems into simpler parts make them more manageable Limited because life’s properties emerge with increasing complexity

L IVING THINGS MUST ACQUIRE ENERGY AND UNDERGO METABOLISM Organisms interact with living and non-living components 2 major processes Recycling chemical elements Flow of energy Some energy is converted to heat Chemical within Light to chemical to KE to thermal energy Energy through Light in & heat out

T HE C ELL : F ORM F ITS F UNCTION Prokaryotic CellEukaryotic Cell Single cells No nucleus or organelles Smaller, less complex Single- or multi-celled Nucleus and other organelles Larger, more complex

C ELLULAR I NSTRUCTIONS All cells have DNA (deoxyribonucleic acid) Direct the development of organisms through protein production Inherited by offspring from parents through reproduction All of the genetic information inherited constitutes an organism’s genome Chemical arrangement of determines function Similar to arrangement of the alphabet into words Contributes to the diversity of life All life forms basically use the same code Can artificially create instructions when necessary

F EEDBACK M ECHANISMS Most common Excess end product halts process Sugar breakdown to ATP; sufficient levels = stop sugar breakdown End product speeds up process Blood vessel damage causes platelets to aggregate = signal more platelets

O RGANIZING AND C LASSIFYING L IFE Different Killer Penguins Crawl OverFrozen Glacial Shores Subheadings exist for all taxons

D OMAINS Bacteria Prokaryotes Most diverse and wide spread Most are singled-celled Archaea Prokaryotes Live in extreme environments (extremophiles) Eukarya Eukaryotes Have a nucleus and organelles

I NTRODUCTION TO E VOLUTION November 1859 Charles Darwin published On the Origin of the Species by Means of Natural Selection Main points Evidence for evolution Descent with modification All living organisms evolved from common ancestry Natural Selection was the mechanism for evolution Pieced together existing information Individual variation and overproduction of offspring Unequal reproductive success and accumulation of favorable traits

T HE P EPPERED M OTH S TORY Prior to England’s Industrial Revolution, vast numbers of these moths existed. Light in color to blend with lichen on trees Afterwards the lichen began to die and the trees became covered in soot. Light colored individuals began to die off. Increase in numbers of darker colored moths appeared. Lighter versions returning with improved environmental standards Biston betularia betularia morpha typica Biston betularia betularia morpha carbonaria,

A NTIBIOTIC R ESISTANCE Antibiotics are used to kill bacteria Mutations for antibiotic resistance exist or arise Antibiotic-resistant bacteria survive and reproduce better than nonresistant Over time, proportion of antibiotic-resistant bacteria increases

T HE S CIENCE OF B IOLOGY Science stems from natural curiosity about the world around us Limited by what we can observe and measure Blends two forms of inquiry Discovery science Verifiable observations and measurements General principles from a large number of specific observations Hypothesis based science Seeking natural causes and explanations for discovery observations Proposing and testing a hypothesis

S CIENTIFIC M ETHOD

L IMITS TO THE S CIENTIFIC M ETHOD Can never concretely prove something (No absolute truths) Hypothesis Theory Law Can’t address supernatural phenomenas Limited by our current knowledge and understanding Can’t answer moral or ethical questions Limited by our fallibility