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Lesson Overview
Meeting Ecological Challenges
Chapter 15
Genetic
Engineering
15.1
Selective
Breeding
Lesson Overview
Meeting Ecological Challenges
Selective Breeding
• Selective breeding –
only organisms with
desired characteristics reproduce.
• Two Types
o Hybridization
o Inbreeding
Lesson Overview
Meeting Ecological Challenges
Hybridization
• Hybridization - crossing dissimilar
individuals to mix best of both.
• Hybrids are often hardier than the parents.
•
•
Ex: Crossing disease-resistant plants with productive
plants.
Ex: Horse + donkey = mule
Lesson Overview
Meeting Ecological Challenges
Inbreeding
• Inbreeding - breeding individuals with
similar characteristics.
– Adv: Preserves characteristics
– Disadv: Increases chances for
genetic disorders.
Copyright Pearson Prentice Hall
Lesson Overview
Meeting Ecological Challenges
Increasing Variation
• Biotechnology – using
technological processes on living organisms.
• Selective breeding is one form
of biotechnology important in agriculture and
medicine, but there are many others.
Lesson Overview
Meeting Ecological Challenges
Increasing Variation
• Breeders can increase genetic variation by
introducing mutations.
• Ex: Oil-digesting bacteria
• Polyploid
(many sets of chromosomes) plants
are larger and stronger than their diploid
relatives.
Copyright Pearson Prentice Hall
Lesson Overview
Meeting Ecological Challenges
15.1 Review
1. What are the two types of selective breeding?
Hybridization and Inbreeding
2. What is the difference between the two types?
H- mixing different things. I- mixing similar things.
3. What are two ways to increase variation?
Introduce mutations and polyploidy
4. What does “polyploidy” mean?
Many sets of chromosomes
Lesson Overview
Meeting Ecological Challenges
Chapter 15
Genetic
Engineering
15.2
Recombinant
DNA
Lesson Overview
Meeting Ecological Challenges
THINK ABOUT IT
Suppose you have an electronic
game you want to change.
Knowing that the game depends
on a coded program in a computer microchip, you’d
need a way to get the existing program out of the
microchip, read the program, make the changes you
want, and put the modified code back into the
microchip.
What does this scenario have to do with genetic
engineering? Just about everything.
Lesson Overview
Meeting Ecological Challenges
Copying DNA
1. Extract DNA.
2. Restriction enzymes –
Cut DNA into fragments.
3. Polymerase chain reaction (PCR) –
used to copy DNA fragments.
Lesson Overview
Meeting Ecological Challenges
Polymerase Chain Reaction
1. Separate
DNA strands.
2. Add DNA
polymerase
to make DNA copies.
3. Use copies to make
more copies.
Lesson Overview
Meeting Ecological Challenges
Combining DNA Fragments
• It can be beneficial to combine DNA
from two different organisms.
• Recombinant DNA –
A gene from one organism that is combined
with the DNA of another organism.
Lesson Overview
Meeting Ecological Challenges
Plasmids and Genetic Markers
• We can transform bacteria using plasmids.
• Plasmids - small circular DNA molecules
in bacteria.
Lesson Overview
Meeting Ecological Challenges
Plasmids and Genetic Markers
• Genetic marker –
a gene used to isolate
only desired bacteria.
Lesson Overview
Meeting Ecological Challenges
Transgenic Organisms
Transgenic – organism
containing genes from other species.
-An organism with recombinant DNA
Lesson Overview
Meeting Ecological Challenges
Cloning
Clone - a
genetically
identical copy
First clone - In 1997, Ian
Wilmut cloned a sheep
called Dolly.
Lesson Overview
Meeting Ecological Challenges
Cloning
Animal cloning uses a procedure called nuclear
transplantation.
1. Nucleus of egg is removed.
2. Egg is fused with donor cell.
3. Egg is placed in foster mother.
Lesson Overview
Meeting Ecological Challenges
15.2 Review
1. What do restriction enzymes do?
Cut DNA
2. What is the process of copying DNA (abbrv.)?
PCR
3. When DNA from two different organisms is combined,
what is it called?
Recombinant DNA
4. If we wanted to isolate specific bacteria, what would we
use?
Genetic marker
Lesson Overview
Meeting Ecological Challenges
15.1/15.2 Review
Each group must pick one of the following to explain. One
person in each group must explain their topic:
A. What is selective breeding? What are the two types (and give
examples).
B. What are two ways breeders increase variation? Explain
them.
C. What are the three steps of copying DNA?
D. What are the three steps of PCR?
E. What are the three steps of cloning?
F. What is the difference between the terms “recombinant” and
“transgenic”?
Section 15-3:
Applications
of Genetic
Engineering
Chapter 15:
Genetic
Engineering
Agriculture and Industry
 Genetic
engineering could give us:
 Less expensive food
 More nutritious food
 Safer manufacturing
GM Crops
 “Genetically
modified”
 Crops resistance to herbicides,
rot, and spoilage
GM Animals
 More
milk, more meat, and leaner meat.
 Clone to save endangered species.
Treating Disease
 Use
recombinant DNA
to make
human proteins
 Insulin,
blood-clotting
factor, cancer-fighting
proteins
 Gene
therapy –
changing a gene to
treat a medical disease.
Treating Disease
 Very
risky
 Need a more reliable way
to insert working genes
 Make sure it’s not harmful
DNA Microarray
 Not
every gene is active all the time
 DNA microarray –
measures activity level of genes
 Colored tags label source of DNA
 Red
spots = more
cancer mRNA
 Green
spots = more
normal mRNA
 Yellow
spots = both
Personal Identification
 DNA
fingerprinting –
analyzes sections of
DNA with little/no
function, but that
vary widely.
Forensic Science
 Forensics
= study of
crime scene evidence
 Uses DNA fingerprinting to solve
crimes, overturn convictions
15.3 Review
1.
What does “GM” stand for? Name benefits.
Genetically modified; less expensive, more quantity,
and disease resistant food.
2.
What is gene therapy?
Changing genes to treat disease
3.
What measures gene activity?
4.
5.
DNA Microarray
What does DNA fingerprinting look at?
DNA sections with little/no function
Why does DNA fingerprinting work?
No two people are alike
Lesson Overview
16.1 Darwin’s Voyage
of Discovery
Darwin’s Epic Journey
– Developed scientific theory
explaining how organisms
evolved over long periods of
time through descent
from common
ancestors  evolution
Darwin’s Epic Journey (cont.)
- Three distinctive patterns of diversity:
(1) Species vary globally
(2) Species vary locally
(3) Species vary over time.
Species Vary Globally
- Different but similar
species live in
separated
habitats around the globe.
• Rhea of SA
• Emu of Australia
• Ostrich of Africa
Species Vary Locally
- Different, yet related,
species occupy
different habitats
within a local area.
- Ex: Galapagos Islands which
are close together but have
different ecological conditions
which lead to very distinct
giant tortoises.
Species Vary Locally (cont.)
– Ex. Darwin’s Finches beak structure
varied depending on their diet.
Species Vary Over Time
- Fossils - preserved
remains of ancient
organisms.
- Some fossils were
similar to
living species.
Putting the Pieces of the Puzzle Together
- The evidence suggested species could
change by natural process.
Review 16.1
1. What theory states organisms evolved over
time from a common ancestor?
Evolution
2. What were three ways Darwin found species
vary?
Globally, locally, over time
naturally
3. Species can change by ________________
processes.
Lesson Overview
16.2 Ideas That Shaped
Darwin’s Thinking
An Ancient, Changing Earth
– Uniformitarianism Processes that changed
Earth in the past
continue to operate in the
present.
Lamarck’s Evolutionary Hypotheses
– Lamarck proposed
organisms change during their
lifetimes by
using or not using
parts of their bodies.
• Acquired characteristics.
– Suggested these traits could be
passed on to offspring
• Inheritance of acquired
characteristics
Evaluating Lamarck’s Hypotheses
– Lamarck’s hypotheses were incorrect.
– Evolution
species becomes “better”
– Acquired traits cannot be passed on
to offspring.
Artificial Selection
– Artificial selection - nature provides
variations, but humans select traits
to pass on.
– Breeders do this for animals and plants.
– Recognized natural variation provided
raw materials for evolution.
Review 16.2
1. The process that changes Earth both in the past
and present is called…
Uniformitarianism
2. Who’s ideas about evolution were incorrect?
Lamarck
3. Why were his ideas incorrect?
Traits are not dependent on use.
4. What is artificial selection?
Humans select natural traits to pass on
Period-Only Poster Project
• Create a poster with
color, pictures, descriptions, and [examples]
of your topic.
• Try & use examples NOT listed in the notes – use internet.
• Topics include:
1. Species vary globally
2. Species vary locally
3. Species vary over time
4. Lamarck’s hypothesis and why it was incorrect
Lesson Overview
16.3 Darwin Presents
His Case
When does natural selection
occur?
– Struggle for existence
– Variation and adaptation
– Survival of the fittest
The Struggle for Existence
– When more individuals are
produced than can survive,
members must compete to
obtain food, living space, and other
limited necessities of life.
Variation and Adaptation
– Adaptation - Characteristic that
increases ability to survive.
• Ex: Camouflage, sharper claws, efficiency,
behaviors
Survival of the Fittest
– Fitness – ability to survive and
reproduce in its environment.
• High fitness - Individuals well-suited to environment
and can reproduce
• Low fitness - Individuals not well-suited to environment
and die without reproducing or leave few offspring
– Survival of the fittest –
Individual with the highest fitness will survive.
Natural Selection
– Natural selection - organisms with best
variations for the local environment survive.
– Environment—not breeder—influences fitness.
– Populations change as they become better adapted,
or as environment changes.
Natural Selection Example
1. Grasshoppers can lay 200 eggs at
a time, but few survive to
reproduce.
2. Variation includes yellow and green
body color.
 Which color is adaptation? Green
3. Green grasshoppers = higher
fitness = survive & reproduce
4. Green grasshoppers more
common because higher fitness in
this particular environment
Natural Selection
– Natural selection does not make
organisms “better.”
– Natural selection doesn’t move in
a fixed direction.
• Changes to fit environment.
• If organism cannot adapt, could go extinct.
Common Descent
– Evolution suggests common descent
- all life descended from ancient common
ancestors.
– Descent with modification –
living species descended, with modification, from
common ancestors.
Review 16.3
1. What three things happen for natural selection
to occur?
-Struggle for existence, Variation and
adaptation, Survival of the fittest
2. Characteristic that increases ability to survive…
Adaptations
3. What does fitness mean?
Ability to survive and reproduce
4. Natural selection can change based on the…
Environment
Lesson Overview
16.4 Evidence of Evolution
Biogeography
– Biogeography - study of where organisms live
today and where their ancestors lived in the
past.
The Age of Earth
- Geologists use radioactive
dating to indicate that Earth is
about 4.5 billion years old.
Recent Fossil Finds
- Paleontologists have
discovered many
fossils believed to be
intermediate
stages.
Comparing Anatomy and
Embryology
– By Darwin’s time, scientists had noted that all
vertebrate limbs had the same
basic bone structure.
Homologous and Analgous Structures
– Homologous
structures shared common
structures
– Analogous
structures shared common
function
Ex: The wing of a bee
and wing of a bird
Homologous or Analogous??
Vestigial Structures
–Vestigial structures –
inherited structures with little to no function.
• Ex: Wings of penguin, ostrich, etc.
– As scientists learn more, many parts thought to be
vestigial actual have function.
• Ex: Tonsils, coccyx
Embryology
– Embryos of many organisms
develop in similar ways
• Used as evidence of common
ancestor.
Only so many ways to do the same thing.
Life’s Common Genetic Code
– All living cells use information
coded in DNA and RNA.
– There are also homologous genes.
• Some Hox genes are found in most multicellular animals
Review 16.4
1. Difference between homologous and analogous?
H= Common structure, A= common function
Intermediate
2. ___________________
fossils link past and
present organisms.
3. What is a vestigial structure?
Structure with little/no function
4. All living cells use what for information?
DNA and RNA