Why Study Biology Biology is relevant Great advances

Why Study Biology? Biology is relevant – Great advances – Bioengineering – Population has grown – Emerging technologies 1

Biology is Relevant Great advances – 19 th & 20 th centuries Disease caused by pathogens – Today Emphasis turning to physiological malfunctions – Past diseases fatal – now treated 2

ANTIBIOTIC RESISTANCE: Superbugs on the Hoof? Dan Ferber, Science 2002 Disturbing new findings have provided a key link in the chain of evidence connecting antibiotics used on livestock to outbreaks of disease caused by antibiotic-resistant human pathogens When the severe diarrhea didn't stop after nine awful days, the 62 -year-old Danish woman dragged herself to the emergency room at Bispebjerg Hospital in Copenhagen. The diagnosis was a cinch: food poisoning from Salmonella. Doctors rolled out their big gun, an antibiotic called ciprofloxacin that can vanquish the nastiest Salmonella strains in a few days. But as the hours passed, the infection worsened-- becoming so bad that the Salmonella punched a hole in her colon, allowing it and other bacteria to invade the rest of her body. As the situation grew desperate, doctors blasted her with heavy doses of two more antibiotics and stitched up her damaged colon. The drugs knocked off the Salmonella, but other escapees from the gut sent her into septic shock; one by one, her organs failed. Four days after doctors realized the Salmonella was impervious to ciprofloxacin, she was dead. 3

Biology is Relevant Bioengineering – New Green Revolution Developed new corn plant varieties Genetically enhanced – Resist pests & drought, cold tolerant – Could help alleviate world hunger 4

Biology is Relevant Population growth should level in 21 st century – Leveling will not be easy or quick – Tough decisions – couples, nations, beyond – Where put new cities, farms, etc. ? – Monitor & manage existing wild areas 5

Scientists Now Acknowledge Role of Humans in Climate Change By ANDREW C. REVKIN October 26, 2000, NY Times Greenhouse gases produced mainly by the burning of fossil fuels are altering the atmosphere in ways that affect earth's climate, and it is likely that they have "contributed substantially to the observed warming over the last 50 years, " an international panel of climate scientists has concluded. The panel said temperatures could go higher than previously predicted if emissions are not curtailed. This represents a significant shift in tone — from couched to relatively confident — for the panel of hundreds of scientists, the Intergovernmental Panel on Climate Change, which issued two previous assessments of the research into global warming theory, in 1995 and 1990. 6

Biology is Relevant Emerging technologies – computers – Will bridge gap between biology & technology – New career opportunities Biotechnology (lab-oriented) Applied technology (field-oriented) Some will straddle lab & field 7

Biology can be Controversial Some controversial questions: – Family planning – birth control? – How much $ to spend – endangered species? – Biomedical research – human fetal tissue ethical? 8

Youth's Death Shakes New Field of Gene Experiments on Humans By SHERYL GAY STOLBERG, January 27, 2000, NY Times WASHINGTON, Jan. 26 -- Perhaps no event in recent medical history has done more to shine light on the inherent conflict of interest between researchers and their subjects than the death of an 18 -year-old from Tucson in a gene therapy experiment at the University of Pennsylvania. It has been four months since Paul Gelsinger made the wrenching decision to withdraw life support from his son, Jesse, after an infusion of gene-altered viruses meant to correct an enzyme deficiency caused an immune response that spiraled out of control. The grieving father then vowed to stand by the Pennsylvania scientists "until my dying day. " 9

Biology can be Controversial questions: – Irradiated food safe to eat? – Dangers cloning animals? Humans? – Are we playing God? 10

Chefs Join Campaign Against Altered Fish By MARIAN BURROS September 18, 2002, NY Times In a pre-emptive strike against the newest genetically engineered food, 200 chefs, grocers and seafood distributors across 40 states plan to announce today that they have pledged not to purchase fish that have been altered through biotechnology. The campaign says it is concerned that if genetically engineered salmon are approved by the Food and Drug Administration, they could escape from the pens in which they are raised and interbreed with wild salmon, endangering some species. The F. D. A. is considering an application to market transgenic salmon. If the application is approved, salmon would become the first genetically modified animal allowed onto American dinner plates, where it would sit alongside genetically engineered corn and potatoes, which have been available for several years. The biotech company producing the salmon says they will be better for the environment than current farmed salmon. 11

Biology can be Controversial Some controversies remain within biology Others involve economic, moral, ethical & religious considerations Biology can help understanding – Identify options – Describe impacts 12

British Scientists Seek Approval to Clone Human Embryos By THE ASSOCIATED PRESS August 16, 2000, NY Times LONDON -- A panel of experts urged the government to allow human cloning for scientific study of transplants, a recommendation that, if approved, would make Britain the first country in the world to authorize human cloning for any purpose. In calling for Britain to amend its ban on human cloning, the government-commissioned panel said scientists should be allowed to create cloned embryos to study the manufacture of cells and tissues for transplant. The government accepted the panel's recommendation, led by Britain's chief medical officer, and said it would initiate legislation to implement it as soon as possible. Ethical concerns have tempered many countries' consideration of cloning technology. 13

Biology The study of life – A way of understanding nature – A human endeavor Strives to … – Understand, – Integrate, and – Describe 14

What is Life? Difficult to define Biologists focus on how life works – For Biologists, life is: That set of characteristics that distinguish living organisms from Inanimate objects 15

What is Life? Living organisms – Highly organized, complex entities – Composed of one or more cells Contain a blueprint of characteristics – Acquire and use energy – Carry out and control numerous chemical reactions 16

What is Life? Living organisms – Grow in size and change in appearance and abilities – Maintain constant internal environment – Produce offspring similar to themselves 17

What is Life? Living organisms – Respond to changes in environments – May evolve into new types of organisms Living organisms possess all of these simultaneously 18

cells nerve cell tissues nervous tissue organs the brain organisms pronghorn antelope populations herd of pronghorn antelope communities 19 snakes, antelopes, hawks, bushes, grass

The diversity of life A. The three domains of life – 1. Bacteria – 2. Archaea – 3. Eukarya 20

The diversity of life B. The importance of biodiversity C. Evolution—the unifying concept of biology – – 1. Genetic variation and inheritance 2. Natural selection 21

Biology: A Branch of Science is a way of knowing the natural world – Science is an activity It’s what scientists do – Body of knowledge derived from that activity 22

Biology: A Branch of Science Biology also differs from Science – Younger Natural science studied for 1000 s of years Physics since the 1500 s – Modern Biology Began with Darwin – mid 1800 s 23

Biology Integrated with other sciences – Organisms subject to laws of physics and chemistry – Mathematics used to analyze & interpret biological data 24

Major Theories of Biology Evolution by natural selection Inheritance Cells Biological Classification Bioenergetics Homeostasis Ecosystems 25

Evolution by Natural Selection Theory has two parts – Species change over generations – Natural selection is mechanism for change Accepted by many scientists as Biology’s most important theory 26

Inheritance Theory Inheritance – intimately connected with evolution How are traits inherited by offspring from parents? – Gregor Mendel’s pea plants 27

Inheritance Theory Mendel’s principles of inheritance apply to all organisms – Traits passed from one generation to next via hereditary factors (genes) – Mendel’s published results Ignored at first in 1865 Rediscovered early in 20 th century 28

Cell Theory Matthias Schleiden & Theodor Schwann proposed Cell Theory – Elements of Cell Theory All organisms are composed of cells All cells come from pre-existing cells The cell is smallest unit capable of exhibiting all characteristics of life 29

Biological Classification Started much earlier than most – Carolus Linnaeus – late 18 th century Classified living organisms by – Similarities – Differences 30

Bioenergetics The energy that powers life Operates according to rules that govern energy – Antoine Laurent Lavoisier, late 18 th century 31

Bioenergetics Antoine Laurent Lavoisier, late 18 th century – Placed chemistry of life into Larger context of physics & bioenergetics Culminated in understanding chemical reactions of cells (metabolism) 32

Homeostasis Claude Bernard – mid 19 th century – Organisms function best when Internal conditions maintained in narrow limits – External toleration via stable internal conditions (organisms) – Stability (homeostasis) maintenance constitutes study of physiology 33

Ecosystems Organisms interact with each other & their environment Changes in biological community can alter other parts – Ecosystem concept Recognizes organisms do not exist alone 34

Ecosystems Youngest of biology’s major ideas – Product of 20 th century – No readily identifiable parent – Diverse group of specialists – Perhaps most complex of concepts Blends biology & other sciences – Backbone of ecology 35

How is Biology Studied? Five Key Words of Biologists Observation Questioning Hypothesis Testing Explanation 36

The Scientific Method The set of procedures that form that rational approach to studying the natural world 37

Scientific Method – How? Observation – Can be something entirely new – A new way of looking at things, or – A realization natural world is at odds with currently accepted ideas – Leads to questions 38

Originally, this greenish bacterial growth covered the entire petri dish. When an experimenter placed a penicillincoated disk of paper in the dish, nearby bacteria were killed. 39

Scientific Method – How? Questioning – some science do not address and can’t – Scientists ask Questions answered by experiment or observation of material universe – Biologists use Observation & experience to ask how or why something happens 40

Scientific Method – How? Hypothesis – tentative explanation, possible answer – In formulating hypotheses, scientists Accept world as real place Believe world is neither chaotic nor dependent upon – Supernatural realm – Metaphysical realm 41

Scientific Method – How? Hypothesis – tentative explanation, possible answer – In formulating hypotheses, scientists Believe events & phenomena of material world have causes Believe simplest explanation is preferred (Occam’s razor) 42

Scientific Method – How? Hypothesis – Always tentative & remain so until rigorously tested – A scientist should be ready to abandon when A better one More consistent with observation is proposed 43

Testing Systematic observations Controlled experiments Detailed studies used to test hypotheses 44

Testing Occupies most of working scientist’s time Begins when – Scientist makes logical predictions – Based on hypothesis 45

Explanation A mature hypothesis, one that has been tested All explanations subject to review & reconsideration when – New evidence is presented – Better explanations are proposed 46

Explanation – Theory Nonscientists believe a theory is – Pure speculation – Without practice or evidence Scientists consider a theory a – Demonstrable, or – Well established principle 47

Explanation – Theory Many explanations in Biology are considered true 48

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