Introduction to Biology

Prologue: The Molecular Perspective

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Biology in Your World

Biology is believed to be the most influential Biology is believed to be the most influential science of the 21science of the 21stst century century

Cancer cures? Genetic engineering / counseling / cloning Stem cells

But, just because we can…should we?

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Ethics and BiologyUsing Knowledge Wisely

Ethics – a system of moral principles to distinguish right from wrongWhat are your ethics based upon?

Public Policy – laws and regulations that govern how science is appliedWhat role do you play in deciding public policy?

Example

http://www.csmonitor.com/USA/Justice/2011/0429/Stem-cell-research-Court-gives-Obama-a-victory-but-policy-still-on-trial

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What is science? An organized way of using evidence to learn about the

natural world

The body of knowledge that scientists have accumulated over time

It is not based on belief or faith, magic, or legend but on actual evidence. Pseudoscience – associating real science to some supernatural

occurrence or pattern without evidence EXs: Palm reading, Astrology, Alchemy, Intelligent Design

Daily Horoscope

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Important Scientific Skills

Observing – process of gathering information using your senses in a careful, orderly way

Inferencing – making a logical interpretation based on prior knowledge or experience Did not eyewitness

Example… Baby was asleep upstairs – heard a loud thump – heard crying What inferences can we make?

http://www.philtulga.com/Riddles.html - Inferencing game

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The Scientific Process Analyzes problems through TESTING

Hypothesis – possible explanation of observations that are testable through experimentation or observation. “If….then”

Theory – a repeatedly tested hypothesis that accurately explains observations and predicts future occurrences. Cell theory, gene theory

Laws – widely accepted and repeatedly tested theories Newton’s Law, Thermodynamics

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Good Scientists….

Are skeptics: they question existing ideas and new hypotheses

Are open-minded: they are always willing to consider new ideas when evidence demands it

Rely on basic natural laws: they understand that the universe functions as a system of interacting processes

Repeat experiments: through an immense amount of research a certain hypothesis might become so well-supported that scientists consider it a theory

Keep up with new knowledge gained through research: they continually revise and re-evaluate ideas. NOTHING IS “FACT”

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What is Life?A fundamental scientific question

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“Life is Organized”

Atoms

C,H,O,N,P,S

Molecules

Organelles

Cells

Tissues

Organs

Organ Systems

Organism

Species

Population

Community

Ecosystem

Biome

Ex: Tundra, desert, temperate forest

Biosphere

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Smallest / most simple

Largest / most complex

How did life begin?An Idea

The Oparin-Haldane Hypothesis (1920s) Verified by Miller-Urey (1953) Built an apparatus to mimic early earth:

Reducing atmosphere;

methane, ammonia, hydrogen Boiled water, shocked it, cooled it Atoms bumped together &

formed hydrocarbons and amino acids!

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Living things…

Are made up of units called CELLS Are based on a universal GENETIC code REPRODUCE GROW and DEVELOP CHANGE over time (evolve) Obtain & Use Materials and ENERGY Maintain an Internal BALANCE

= homeostasis RESPOND to their Environment

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All organisms are uniquely

adapted for their environments.

Scientists know that over long periods of time organisms have changed or adapted to better survive in their environments.

They call this slow process of change evolution.

Natural Selection: Those best adapted survive and reproduce.

EVOLVEWhy does a duck have a rounded bill and a heron have a long pointed bill? 

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Life BEGINS…

CELLS with DNA are passed on through

REPRODUCTION

An organism GROWS and DEVELOPS to an age where it can REPRODUCE.

Over time, subtle changes are introduced through mutation of DNA. These changes are selected for, leading to EVOLUTION of a population.

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A Mechanism for A Mechanism for Evolution: Science at Evolution: Science at

WorkWork

The formulation of a Theory

An Example of The Scientific Process

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Jean Baptiste Lamarck (1744 – 1829)

Organisms change over time by using or not using certain features. These acquired characteristics are then passed onto offspring

“Use or Disuse” “If a male and a female increase the size of their

muscles through weight training, then their children will be born with large muscles.”

Mr. Palmé as a 5 yr

old

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Was Lamarck right?

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Charles Darwin (1809 – 1882) A naturalist on a 5-year voyage of the Beagle around the

world Observed numerous, diverse organisms

Influenced by the geologists, Charles Lyell and James Hutton, who proposed uniformitarianism (everything in the

universe acts under the same laws of physics) Geological forces existing in the past are similar to the

forces of today and in the future

Proposed the mechanism of evolution Natural Selection

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Theory of Natural Selection

Organism best suited (specific traits/characteristics) for the environment would survive and reproduce.

The suitable traits would be passed on to their offspring.

The specific traits or characteristics are called adaptations

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Is this how Evolution works?

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Survival of the Fittest

Thomas Malthus (economist) noticed that species numbers exceed food supply

In order to pass on characteristics, an organism must eat enough to live to reproduce. Ultimately, the only organisms alive are those with beneficial

adaptations

What are some adaptations?

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Darwin’s Predictions If organisms with favorable variations are most likely to survive

and reproduce, then those organisms with unfavorable variations would be less successful at reproduction and die out.

If organisms with those favorable adaptations become so different from members of the original species that they can no longer reproduce together, then a new species may have evolved.

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Was Darwin Right?

Whose to say but… Experiments repeatedly show same results

Descent with Modification – related organisms share a common ancestor The greater the similarity between two groups of

organisms, the closer their relationship How is this studied today?

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