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Genetics and Species Survival
What makes you, you?
Genetics and Species Survival
 Our starting point is sex.
 Does everything have sex?
 Classify the organisms – have sex, don’t
have sex, unsure.
•Feed back to the class and debate.
Genetics and Species Survival
 Definitions
 Sexual reproduction (making offspring by
sex) – 2 parents
 Asexual reproduction (making off spring
but no sex) – 1 parent.
 Most large living things reproduce sexually.
Genetics and Species Survival
 Why have sex? It’s not issue free ….
You have to learn
all
the
right
Sometimes the girl
you
fall
forupthe
ofSometimes
your dreams
You
have
to
get
dressed
to
moves
Concentrating
on
sex
means
you
wants to eatwrong
your a mate
attract
partner
(eofdreams.com)
Sometimes
the last
thing you do.
forgetit’s
about
surrounding
dangers
head.
Friendships suffer
Genetics and Species Survival
 Sex must be very valuable for so many
things to do it when there are so many
dangers.
 So what is sex?
Write a definition of sex based on our
discussion.
Genetics and Species Survival
 Before we can continue on to discuss why
the living world bothers with sex we need to
see what the alternative is.
 Well the cells in your body are reproducing
all the time without having sex.
 See mitosis app.
Genetics and Species Survival
 Reproduction
without sex is
quite popular
really
 It is called
asexual
reproduction.
Genetics and Species Survival
 Asexual reproduction produces offspring
that for the most part are identical to the
parent.
Genetics and Species Survival
 The information that goes to make the off
spring in asexual reproduction comes from
the one parent so we get more or less exact
copies.
 The information that goes to make the
offspring in sexual reproduction comes
from two parents no exact copies.
 What carries this information and where is
it?
Genetics and Species Survival.
 Familiarisation with cells – a bit of
microscope work.
 Reminder about how to use
 Reminder how to make a stained slide
 Examine slides of cells. Record images to
pass on to whole class.
Might need to look at this
Genetics and Species Survival
www.yalemedi
calgroup.org
Genetics and Species Survival
ohyeahdevelopmentalbi
ology.tumblr.com
Genetics and Species Survival
 In the 1950s it was discovered that the
chromosomes were made of a chemical
called DNA and that it had a double Helix
Structure.
 Practical Investigation: - Extracting DNA.
 It’s really easy, especially if you have a lot
of material to work with.
Genetics and Species Survival
So the chromosomes and the DNA they are
made from seem to be the message carrier.
What sort of messages to they carry?
Investigation: How different are you from the
other members of the class?
Genetics and Species Survival
 Discussion: What did the exercise with the
cards tell you about your similarity to
others?
 How many selections on average did it take
to arrive at an individual?
 This activity involved phenotypes – rather
than directly looking at your genes it looked
at the effects your genes had on you and
your behaviour.
 Definition: Write a definition of phenotype.
Genetics and Species Survival
 Investigation: Following phenotypes
through a family.
 Aim: To see how genetic traits (phenotypes)
have passed through a family and see if it
assists in mapping genotypes (we don’t
know that term yet …)
Genetics and Species Survival

Equipment:
–

1.
2.
3.
Large sheet of paper, coloured pencils.
Procedure:
Choose one of the characteristics from the card.
(preferably one that was positive for you)
Draw up a blank family tree for your family (yes
include anyone who shares a parent with you,
aunts and uncles, and grandparents.)
At home check with family members if your tree
is okay and which members of that tree have the
characteristic.
Genetics and Species Survival
 Okay break in the investigation as you have
to follow up with your families … seriously
grandparents don’t mind a phone call from
their grandchildren even if it is for a school
assignment.
Genetics and Species Survival
 Inheriting genes through sexual
reproduction. Some mechanisms.
 Later we’ll look at how chromosomes carry
these messages about you but now we’re
going to look at how you inherit them.
 Note: There are lots of methods and often
your traits are formed from a combination
of genes in complex ways – we’re going to
look at simple ways.
Genetics and Species Survival
 Blue eyes and non-blue eyes.
mrbarlow.wordpress.com
Even eye colour can get complex – we’re keeping it
simple.
Genetics and Species Survival
 First another divergence into sex.
 The two sex cells are created in a similar
way to new cells (mitosis) but each sex cell
only receives one of each pair of
chromosomes (meiosis) rather than both
Only half the
chromosomes.
Poor things
Genetics and Species Survival
 Which of any pair they receive is
determined by pure chance.
 So when an egg is fertilized by a sperm it
will have two of each chromosome – one
from each parent.
 Which chromosome it gets is down to
chance.
 There’s a more involved activity about this
coming up.
Genetics and Species Survival
 You receive two genes for eye colour – one
from each parent.
 The gene can either be for blue eyes (b) or
non-blue eyes (B)
 There are four possible combinations in all
– bb – Bb – bB – BB
 As you can see two of the combinations are
the same.
 But it depends on which combination the
parent has.
Genetics and Species Survival
 The genes for blue eyes (b) are recessive.
 This just means that if one gene is b and the
other is B the blue eyed gene loses and the
eyes aren’t blue.
 Let’s see some scenarios.
Genetics and Species Survival
Parent with blue eyes
b
b
B
Bb
Bb
B
Bb
Bb
Genetics and Species Survival
Parent with blue eyes
B
b
b
b
Bb
Bb
bb
bb
Genetics and Species Survival
Brown eye parent
B
Brown eye
parent
BB
B
b
Bb
b
Bb
bb
Genetics and Species Survival
 Here’s your turn to see if you can use these
methods to make predictions.
Genetics and Species Survival
 Intermediate inheritance.
 Sometimes two genes combine to give
something in between
 E.g. curly hair and straight hair giving wavy
hair.
 This can become very complex especially if
more than one gene plays a part.
 All in all – lots of chance for variety.
Genetics and Species Survival
 Creating model DNA
 Here are the three different methods
 Method 1
 Method 2
 Method 3
 Lucky dip to see which one your group gets
 There are lots more options on the web.
Genetics and Species Survival
 The bases on the DNA chain code for a
particular amino acid (these make proteins).
 So for each of the bases a particular amino
acid is put in place. The chain of the amino
acids makes a protein.
 Some bits of the DNA chain mean start and
other bits mean stop – important
instructions when making a protein.
Genetics and Species Survival
Genetics and Species Survival
 It’s time we reproduced.
 Not quite what I meant
 Meet the parents
 Here are the body parts (phenotypes) 1 2
 Here are the genotypes Male and Female
Genetics and Species Survival
 Breeding and Genetics Investigation:
 Select the tokens for the genotypes for each
parent (two tokens for each trait –
Female/Male, heavy/dainty feet,
muscle/tentacle arms, angry/vacant eyes)
 Each parent should have two tokens for
each trait.
 Randomly select a token from each parent
for each trait.
Genetics and Species Survival
 Write out the genotype for the offspring
– Example
– Eyes Cc, Legs SS, Arms tt, and Sex XY
 Create your child … (you might need help
so ask)
 A few years have passed and your child has
matured. Repeat the above steps but choose
someone else in the class with whom to
reproduce.
Genetics and Species Survival
 Create an extended family tree for the
creatures.
 What does the family tree tell us about
inheritance in dominant and recessive
situations?
Genetics and Species Survival
 Following disease through a family tree
activity.
Genetics and Species Survival
 Genetic Engineering
 Introductory video/ New Scientist Article
 Brief Research Activity – to gain some
background and ideas
 Class discussion – how do changes in
genotype affect phenotype
– Give examples from research
– Suggest and discuss possibilities
 Ethical statement about Genetic
Engineering
Genetics and Species Survival
 How should genetic information be used by
society
 Viewing Gattaca
 Response (whatever form works for you)
–
–
–
–
How possible?
Benefit/Harm
Ethical considerations
Your personal position.