SCIENCE (SEMI-FINALS)
BIOLOGY AND CHEMISTRY
• Charles Darwin and Evolution
Early 1800’s – French naturalist, Jean-Baptiste
Lamarck – developed a more concrete theory
about organic evolution
Charles Darwin – born in 1809
- At the age of 22, he ventured on an expedition
Evidence of Evolution
- Darwin’s On the Origin of Species
→ Fossil records – usually found in the sedimentary
layers
→ Biochemical evidence – nitrogen base
sequences in the genetic code
→ Comparative anatomy – seen mainly in the
biological structure of animals
→ Observable events – shows that evolution is an
ongoing process
Evolution – defined as any change in the
inheritable traits within a certain population
Natural selection – basic and central mechanism
of evolution of reproduction in this process
Artificial selection – selective breeding of
domesticated plants and animals
Genetic variation – the difference between cells,
individual organisms
Speciation – evolutionary process in which new
species arise
Related Concepts to Speciation
Species – Latin word specio for “kind” or
“appearance”
Taxonomy – branch of biology that deals with
naming and classifying the diverse forms of life
- Carolus Linnaeus : Father of Taxonomy
Biological Species Concept – views species as a
population whose members have the ability to
interbreed and produce fertile offspring
Other Species Concepts
Morphological species concept – is how scientists
were able to identify more than 1.8 million species
Ecological species concept – based on the
ecological environments or niche
Polygenetic species concept – based on unique
genetic history
Keystone species – those that exert influence or
control in their community structure
CHEMISTRY
GAS LAWS
• Gases have very low density
- Density is a useful property of matter.
└ KMT: Molecules are far apart
• Gases diffuse easily
└ KMT: Random motion in all directions
• Gases have no definite shape and volume
└ KMT: Particles move randomly in all directions
• Gases exert pressure
└ KMT: Molecules collide with the walls
• Gases are easily compressible and expandable
└ KMT: Large distance between molecules
Scientific theory – well-substantiated explanation
of some aspects of the natural world
Boyle’s Law: Pressure and Volume
→ Robert Boyle (1627-1691) studied the effects of
pressure and volume of gas
Relationship: (INVERSE)
P ∝ 1/V
Constant: n, T
Equation:
P1V1=P2V2
Pressure – the impact force per unit area
Charles’s Law: Volume and Temperature
→ Jacques Charles (1746-1823) duplicated the
experiment done by Joseph and Etienne
Montgolfier on June 4, 1783 in Annonay, France.
Relationship: (DIRECT)
V ∝T
Constant: n, P
Equation:
V1/T1=V2/T2
Absolute 0 (0) – lowest temperature possible
Amontons’s Law: Pressure and Temperature
→ Guillaume Amontons (1663-1705) investigated
the
relationship
between
pressure
and
temperature in gases.
Relationship: (DIRECT)
P∝T
Constant: n, V
Equation:
P1/T1=P2T2
760 mm Hg – equivalent of 1 atmosphere of
pressure