Transcript Edges of Life - University of Arizona

Usefulness of
evolutionary science
Corn
There are many
varieties with
different uses
Types of corn
• Dent (Zea mays indenata):
Dent corn is often used as
livestock feed, in industrial products, or to make processed foods. Dent corn is
also frequently referred to as "field" corn. Either white or yellow, dent kernels
contain both hard and soft starch that become indented at maturity.
• Flint (Zea mays indurata):
Flint corn is also known as
Indian corn and has a hard outer shell and kernels with a range of colors from
white to red.
• Sweet (Zea saccharata or Zea rugosa):
Sweet corn is
primarily eaten on the cob. Sweet corn is extra sweet because it contains more
natural sugars than other types of corn.
• Flour (Zea mays amylacea):
Flour corn is used in baked
goods because it has a soft, starch-filled, kernel that is easy to grind. Flour corn
is primarily white, although it can be grown in other colors, for example, blue
corn. One of the oldest types of corn, flour corn was a chief type grown by
Native Americans.
• Popcorn (Zea mays everta):
Popcorn, a type of flint corn,
has a soft starchy center surrounded by a very hard exterior shell. When
popcorn is heated the natural moisture inside the kernel turns to steam that
builds up enough pressure for the kernel to explode. All types of corn will pop to
some degree, but they won't necessarily have enough starch to turn inside out,
or an outside layer that will create enough pressure to explode . One of the
oldest forms of corn, evidence of popcorn from 3600 B.C. was found in New
Mexico!
The wild plant that gave rise to corn
Origin of corn from a wild plant
Corn
Native Americans were great evolutionists!
They made teosinte evolve into dozens of
corn varieties.
Origin of corn from a wild plant
How did Americans change teosinte
into corn?
Preventing insecticide resistance
Where else in
agriculture is
understanding
evolution
important?
• Insect pests evolve
resistance
• This can be
prevented by
creating “refugia”
Preventing drug resistance
Drug resistance – an evolutionary
adaptation of bacteria
• Pathogens (bacteria, fungi, parasites)
can evolve resistance to antibiotics or
other drugs
• We can prevent this by:
– alternating multiple different drugs
– in HIV therapy, by taking breaks
where no drugs are taken
Use of evolutionary theory in engineering
“Evolutionary algorithms” used in
engineering
• Engineers let
designs “evolve” in a
computer
• By simulating
“mutations”
(variation) and
reproduction of
“successful”
(desired) variants
Summary
Genes
• Each cell contains a complete copy of
an organisms genome on a long
strand of DNA
• A “gene” is a section of DNA that gets
translated into a protein
• Proteins make up machines, skeleton,
and color of cells  and therefore
determine form and function
Summary
Inheritance
•
•
•
Most organisms inherit a set of genes from
their father and one from their mother: they
have sets two total
The two genes for a particular trait may be
the same or different alleles (variants). If
they are different, one may be dominant
over the other (brown over blue eyes).
Knowledge of genetics is used in many
fields, particularly agriculture and medicine