Introduction to Biology

Prologue: The Molecular Perspective

Bio 391

Why should you care?What is Science?What is Biology?What is Life?Evolution – What does this major theory say?

Biology in Your World

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

What are some of the ways biology impacts your life now?

In the future?

But, just because we can…should we?

Ethics and BiologyUsing Knowledge Wisely

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

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

Ethics in Biology

Stem cells in research/treatment Prenatal genetic testing for diseases Genetic testing for susceptibility Biotechnology for altering self or offspring Genetically modified (GM) food What are some others?

Science as a way of Knowing

If you are a thinker, you question things you observe and may not understand and you try to find an answer. There are many ways to find these answers. If you are a scientific thinker you find your answer using the scientific method.

Example: Why is the sky blue?

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. It is concerned with the natural world, not the supernatural world

This is pseudoscience

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

Example…

The Scientific Process Analyzes problems through TESTS

Hypothesis – 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.

Laws – widely accepted and repeatedly tested theories Can you name any?

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”

What is Life?A fundamental scientific question

What is the difference between you and your desk?

Is a fallen apple alive?

“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

How did life begin?

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!

Early Life Everything is just a bunch of atoms Life began in the sea Oxygen was not used for respiration

How did Oxygen become plentiful?

Evolutionary tree Classification system

Classification

Biologists group organisms to show similarities and proposed relationships. Based on the Theory of Evolution Descent with Modification

Classification systems change with expanding knowledge about new and well-known organisms

Kingdoms and Domains

Three Domain System (based on rRNA evidence)

Six Kingdom System (based on rRNA evidence)

Traditional Five Kingdom System

Bacteria Archaea Eukarya

Bacteria Archaea PlantaeProtista Fungi Animalia

Monera Protista Plantae Fungi Animalia

Humans = .00009%

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 RESPOND to their Environment

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? 

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 ‘s are selected for, leading to EVOLUTION of a population.

Recap How do the 8 characteristics of life apply

to you? What Kingdom do we belong to? What is a theory? What is ethics?

A Mechanism for Evolution: Science at Work

P.5: The formulation of a Theory

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.”

Was Lamarck right?

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 (1797-1875) and James Hutton, who proposed uniformitarianism Geological forces existing in the past are similar to the

forces of today and in the future

Proposed the mechanism of evolution Natural Selection

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

Is this how Evolution works?

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?

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.

Was Darwin Right?

________ 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?

Recap What is the difference between Lamarck

and Darwin’s ideas? (use an example) Give an example of an adaptation What is uniformitarianism? What makes a theory different than a

hypothesis?

Other Accepted Theories

Cell Theory: All organisms are composed of one or more cells, and those cells have arisen from pre-existing cells

Gene Theory: The Central Dogma that

DNA RNA proteins. DNA is inherited and expressed as protein traits.

Homeostasis: maintenance of a constant/dynamic equilibrium