Why Study Biology?

Biology is relevant

 

     Great advances

      19th & 20th centuries -Disease caused by pathogens

      Today - Emphasis turning to physiological malfunctions

      Past diseases fatal – now treated

     Bioengineering

  New Green Revolution

         Developed new corn plant varieties

         Genetically enhanced - Resist pests & drought, cold tolerant

      Could help alleviate world hunger

     Population growth should level in 21st century

      Leveling will not be easy or quick

      Tough decisions – couples, nations, beyond

      Where put new cities, farms, etc.?

       Monitor & manage existing wild areas

     Emerging technologies – computers

      Will bridge gap between biology & technology

      New career opportunities

Biology can be Controversial

 

     Some controversial questions:

      Family planning – birth control?

      How much $ to spend – endangered species?

      Biomedical research – human fetal tissue ethical?

      Irradiated food safe to eat?

      Dangers cloning animals? Humans?

      Are we playing God?

     Some controversies remain within biology, others involve economic, moral, ethical & religious considerations

What is Biology?

     The study of life

      A way of understanding nature

      A human endeavor

What is Life?

Difficult to define; Biologists focus on how life works

     Living organisms

      Highly organized, complex entities

      Composed of one or more cells

      Acquire and use energy

      Carry out and control numerous chemical reactions

      Grow in size and change in appearance and abilities

      Maintain constant internal environment

      Produce offspring similar to themselves

      Respond to changes in environments

      May evolve into new types of organisms

     Living organisms possess all of these simultaneously

 

Biology: A Branch of Science?

 

     Science is a way of knowing the natural world

     Integrated with other sciences

      Organisms subject to laws of physics and chemistry

      Mathematics used to analyze & interpret biological data

       

Major Theories of Biology

        Evolution by natural selection

        Inheritance

        Cells

        Biological Classification

        Bioenergetics

        Homeostasis

        Ecosystems

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

 

Inheritance Theory

        Inheritance – intimately connected with evolution

        How are traits inherited by offspring from parents?

        Mendel’s principles of inheritance apply to all organisms

      Traits passed from one generation to next via hereditary factors (genes)

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

Biological Classification

         Classified living organisms by similarities/differences

Bioenergetics - The energy that powers life

        Operates according to rules that govern energy

         Larger context of physics & bioenergetics

         Culminated in understanding chemical reactions of cells (metabolism)

Homeostasis

  Organisms function best when

         Internal conditions maintained in narrow limits

      External toleration via stable internal conditions (organisms)

      Stability (homeostasis) maintenance constitutes study of physiology

Ecosystems

        Organisms interact with each other & their environment

        Changes in biological community can alter other parts

      Ecosystem concept recognizes organisms do not exist alone

How is Biology Studied?

 

The Scientific Method

 

The set of procedures that form that rational approach

to studying the natural world

     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

       

     Questioning

      Scientists ask questions answered by experiment or observation of material universe

      Biologists use observation & experience to ask how or why something happens

         Hypothesis – tentative explanation, possible answer; always tentative & remain so until rigorously tested

Testing

        Systematic observations

        Controlled experiments

        Detailed studies used to test hypotheses

        Occupies most of working scientist’s time

        Begins when scientist makes logical predictions based on hypothesis

Explanation

        A mature hypothesis, one that has been tested

        All explanations subject to review & reconsideration when

      New evidence is presented or better explanations are proposed

Theory

        Nonscientists believe a theory is pure speculation, without practice or evidence

        Scientists consider a theory a demonstrable, or well established principle

        Many explanations in Biology are considered true

 

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