Transcript The Best Selection

Natural & Artificial Selection
Web Quest
This assignment is due at the end of the period.
In some cases you will be given specific web links
which will help you with a task. In other cases you
must do your own research.
Play this power point as a slide show so you can click
on web links.
Green bugs show up more on
tree bark than brown bugs do.
Natural Selection
Nature “selects” which
individuals will survive –
those with the best
characteristics adapted to
their environment.
Birds eat the green bugs
because they are easier to see.
This leave mainly brown bugs available
to reproduce … and they produce
brown offspring.
Over time the green bugs die out while
brown bugs survive.
Charles Darwin
• in 1859 Darwin published
Origin of Species by
Means of Natural
Selection
• his theory of natural
selection came from
exploring & collecting
specimens from different
habitats … most
notably… from the
Galapagos Islands
• the Galápagos finches
illustrated how the fittest
or best-adapted organism
for a specific environment
survived
The Theory of Natural Selection
• all organisms produce more offspring than
can possibly survive
• there is incredible variation within each
species
• some of these variations increase the
chance of an organism surviving to
reproduce
• over time variations that are passed on
lead to changes in the genetic
characteristics of a species
Natural selection
“creates” a species that
is better able to survive –
due to its characteristics
or behaviors.
For example, look at the katydid (a type of cricket) in the
picture. Over time crickets that had a the best leaf-like
appearance survived more often because they could
hide from predators. Now this is the normal or most
common appearance for the species.
Artificial Selection
Humans select individuals with desired traits and breed
them to produce offspring also with those traits. This is
called selective breeding. Its like “intentional reproduction”.
Over time only those traits will survive – sometimes
creating one or many new species.
For example, archaeological records show that
dogs have been domesticated for over 14,000
years. They started as wolves who were more
tame and stayed around early human camp
sites. Over time the wolf pups became tamer
and tamer, and humans started breeding those
animals that had desirable traits – such as for
hunting, herding or companionship. Today
there are hundreds of different types of dogs…
all descendants from the wolf.
CORN
Here are some
examples of artificial
selection from the
world we live in.
Have you ever heard of purple,
white or yellow carrots.
Percherons – horses bred
to do heavy work.
Scottish Highland Sheep – bred to
withstand cold, harsh winters.
CLONING
Biotechnology is humans
using technology to speed
up or improve on artificial
selection.
ARTIFICIAL
REPRODUCTION
GENETIC
ENGINEERING
Cloning
Making a genetically identical
copy of a living organism.
Click on this icon for
some info on cloning.
Dolly the sheep was the first animal ever
to be cloned… it happened in 1996. She
was an exact copy of her mother.
Artificial Reproduction
Using technology to help create a new life
Artificial Insemination
Watch the
Video
Read the
News
In Vitro Fertilization
Genetic Engineering
Any technology that directly alters the DNA of an organism.
ACQUACULTURE
Genetically Modified Crops
Read About
Acquaculture in Canada
Learn about Genetically
Modified Fruits & Vegetables
Watch a Video
TRANSGENETICS