Biology: The study of life.

EEES 2150- Biodiversity
Biology: Evolution, Diversity, and Ecology
Biology:
The study of life.
Some Properties of Life
Order
Reproduction of Own Kind
Growth and Development (Differentiation)
Utilization of Energy
Response to Environmental Stimuli
Homeostasis (Internal Environment)
Evolutionary Adaptation

Some Properties of life: Order
Reproduction
Growth and Development
Energy Utilization
Ten Underlying Biological Themes
1. Biological organization and its structural hierarchy:
 
Atoms
↓
Molecules
↓
Organelles
↓
Cells
(Single and as subunits)
↓
Multi-cellular Organisms
(Specialization into tissues, organs, organ systems)
↓
Beyond Individual Cells
(Groups of organisms in same species = population; of different species = communities; and when one adds the non-living, environmental components = ecosystem)

***Each level in the biological hierarchy has its own novel properties; these are called emergent properties.
The hierarchy of biological organization 
Terrestrial Biomes
Marine Biomes

Climograph
The cell is the basic unit of life.

(Robert Hooke, 1665, first described cells; Antoine von Leeuwenhoek studied pond water, etc.). In 1839, it was proposed that all life was composed of single cells.
 
Two main types of cells – all contain DNA (molecule that makes up chromosomes, which contain the genes that tell cells how to differentiate).

- Prokaryotic (no organelles) = bacteria, Archae

- Eukaryotic (organelles) = all other forms of life

3. Continuity of life based on a heritable universal genetic code in the form of DNA.
 
- DNA (Deoxyribonucleic acid) molecule contains instructions for producing new organisms.
 
- Each DNA molecule consists of two long chains in a double helix. Chains consist of four molecules called nucleotides: adenine, guanine, cytosine, thymine.
 
- Replication (exact) of DNA allows for life’s continuity and mistakes are the driving force for evolution (mutations).
 
- All the nucleotides are organized into genes.

-All genes together = genome.
Structure and function are correlated.

If you know one, you can intuit the other.
For example, a bird’s bones are mostly hollow…
 


Form fits function
Organisms interact with the environment.
They take in energy and resources from the environment, and often convert these to different more-useful formats.
They exchange energy and materials with the environment.
These interactions mean organisms are open systems.
Living Organisms Have Regulatory Systems.

E.g., If we take in food, its energy is given off via controlled (regulated) chemical reactions to produce life functions and some heat. If we burn the food, energy is given off only as heat (unregulated chemical reactions).
 
- Controlled process is catalyzed by enzymes  function as regulatory mechanisms.
 
Negative feedback, Feedback inhibition
- Final product inhibits first enzyme, so no more product is produced.
 
Positive feedback
- Product enhances the rate of an enzyme in the reaction sequence.
7. Unity & Diversity are “hallmarks” and are linked.
 
Earth has approximately 1.5 million identified species with estimates of 5-10 million once all are known. Two questions emerge:
 
- How did we get all this diversity?
  - Is there an underlying unity to life?
 
To answer these questions, organisms have been placed into groups that form a framework to study diversity via interrelationships between living organisms.

 the current classification system:
 

Presently, there are 3 groups to which all organisms belong  domains:
1. Bacteria
2. Archae
3. Eukarya
And 5 Kingdoms:
1. Monera (prokaryotes)
2. Protista (unicellular)
3. Plantae (multicellular, photosynthetic)
4. Fungi (multicellular, saprophytes)
5. Animalia (multicellular, ingest other organisms)
Evolution is the core theme of biology.

Evolution with a universal genetic code provides link between unity and diversity.

 

Darwin (1859), Origin of Species
1. Species arose from common ancestors = evolution.
2. Evolution is driven (mostly) by natural selection.
a. Members of a population vary. Variation is heritable.
b. Struggle for existence due to a limitation in natural resources.
c. Population members that succeed pass on their traits to offspring and change the make-up of the succeeding population. Over time, these changes can lead to the creation of new species.
Evolutionary adaptation is a product of natural selection
Poorwill
South America
How to classify all this diversity?
Science: a process of inquiry based on repeatable observation and testable hypotheses.

- Defined generally as an inquiry into life.
- With either of two methods:
1. Discovery
2. Hypothesis/Deductive experimentation
 
a. Discovery
a. Observation of natural processes
b. Identification of new species
c. Discovery of antibiotics
 
- Discovered data can be used to make inductive conclusions (For example: all organisms are made of cells, all trees photosynthesize and are made of cells, thus all organisms photosynthesize.) that aren’t always correct.
 

b. Hypothetico/Deductive
a. Scientific method: ask questions; form an answer (hypothesis); predict; experiment; review hypothesis and determine if the data support the hypothesis or if it is in need of revision.

CASE STUDY (p. 18)

- Hypothesis: Feeding preferences by two different predators cause life histories of guppy populations to change in contrasting ways.

- Can be generalized with enough observations to form a theory.

- Theory: Populations evolve by natural selection because of feeding preferences of predators.
 

10. Science, Technology, Society.

Science and technology (often “applied” goal-oriented science) are products of society.
Science forms basis for new technologies to be developed. These affect society positively and negatively.
New technologies often drive new science.
Examples?