Transcript rep_ and dev

Reproduction and
Development – ensures that
The species lives on – passes
On genetic info.(DNA)
Genetic material = DNA - made of genes, are
Located in the nucleus of all cells
On x shaped structures called
Chromosomes. Humans have 46
Chromosomes in a normal cell.
Asexual reproduction –
One parent, offspring are
Exact copies (clones), same
DNA.
Mitosis – most common form
Of asexual reproduction.
In Mitosis the cell simply
Makes an exact copy of
Itself by dividing.
All living things depend on
Mitosis to create new cells
And to grow – Very important
We make new skin, hair etc.
MITOSIS
In mitosis the genetic
Material, DNA doubles then
The cell splits and each half
Gets a set of DNA.
This is DNA replication =It
Copies itself exactly.
.
Mitosis is AKA Mitotic
Cell division
All individual cells reproduce
By mitosis, a very important
Process.
Examples = paramecium,
Algae, all of our individual
Body cells except gametes.
Cloning – produces identical
Offspring by inserting a
Nucleus into an egg cell.
Cloning – produces identical
Offspring by inserting a
Nucleus into an egg cell.
The nucleus is removed from
An egg cell and any cell
Nucleus from the desired
Clone is implanted in that
Egg cell and then developed
Usually inside a surrogate
Mother.
Dolly
The $155,000 CLONED PUPPY
2 major types of cloning
Therapeutic vs reproductive
Therapeutic – embryo not put
In a “mother” – can develop
Into stem cells.
Reproductive – develops
Into exact copy of organism
Stem cells can be used to develop / grow
Specialized tissues , organs .
This could save lives – prevent/reverse
Diseases – disorders but has GREAT
Moral issues. – Is it right to do ???
Brain Buster Question!!!
Dolly died of lung cancer. Would the
birth mother of Dolly be at the same,
an increased, or decreased risk of
getting the same cancer?
………..Explain your answer.
Technically cutting a piece
From a plant and potting it
Is also cloning. An amoeba
Dividing by mitosis is also
Cloning.
Sexual reproduction – half the
Genetic material provided by
Each parent (sperm and egg
Cells = gametes)
Meiosis – a type of cell division
That occurs only in sex cells
(gametes = sperm and egg)
Meiosis cuts the chromosome
Number in half from 46 to 23
In sex cells
In sperm cells one sperm cell
With 46 chromosomes divides
Into 4 sperm cells with 23
Chromosomes.
In egg cell meiosis one egg
Cell with 46 chromosomes
Divides into one functional
Egg with 23 chromo. And 3
Nonfunctional cells.
How Many Chromosomes Should
be on each line?
Mother _____
Father _____
Meiosis ↓
Meiosis ↓
egg
_____
sperm _____
» Fertilization
Zygote _____
Mitosis ↓
Embryo _____
Mitosis ↓
baby ______
In meiosis the chromosomes
Randomly mix and line up in
Many different patterns which
Causes great genetic variation
Meiosis is responsible for
Great genetic variation.
Crossing over – during
Meiosis some segments of
Chromosomes are exchanged
Which creates new genetic
Variations.
Crossing over
Fertilization – egg meets
Sperm – fertilized egg is
Known as a ZYGOTE
Zygote contains genes from
Both parents that have
Recombined, this is known
As recombination.
Differentiation – after fertilization the
Zygote copies itself repeatedly by
Mitosis.
Zygote ---
Cell divides, but gets no
Larger = differentiation
(develops)
Zygote
Zygote goes through many
Divisions by mitosis known
As differentiation.
Embryo – early stages of
Development , after zygote
About 28 days
Fetus = after 2 months
?????
????????
Zygote goes through many
Divisions by mitosis known
As differentiation.
Embryo – early stages of
Development , after zygote
About 28 days
Fetus = after 2 months
Gene expression -if gene is
Actively producing its
Proteins , trait is present.
Can be influenced by the
Environment.
Ex = plant grown in dark is
White, sun needed to
Stimulate chlorophyll
Human reproduction
Female –
Ovaries – store eggs and make
The hormones estrogen and
Progesterone.
Oviduct – tube connecting
Ovaries and uterus – if sperm
Are present fertilization
occurs
Here = Oviduct
Uterus (womb) – this is where
The zygote attaches to the
Wall and develops into a
Fetus
Umbilical cord – connects
Mother and fetus – actual
Exchange occurs through the
Placenta – attached to wall of
Uterus.
Umb. cord
Placenta
Of uterus
Fetus may be harmed by moms
Actions such as drug use,
Smoking, alcohol, poor diet,
Mom having measles, AIDS or
Other illnesses as fetus is
connected
To moms blood stream.
Placenta – actual site of
Exchange with fetus & mom
Sonogram
Male reproductive stuff
Testes – produce sperm,
And hormone testosterone,
Which influences sexual
Development. Meiosis
Happens here.
Scrotum – maintains proper
Temp for sperm production
( a few degrees cooler)
Cowpers glands
Prostrate
Other reproductive glands
And structures (prostate and
Cowpers)
Produce fluids for sperm to
Swim in (semen)
Penis – deposits sperm
Hormonal regulation –
Females – 28 day egg release
Cycle controlled by hormones
(estrogen & progesterone –
Thicken uterus lining). =
Menstrual cycle
Males – testosterone – sperm
Production & 2ndary sex
characteristics
Twins
Identical = zygote splits into
2 zygotes during first stages
Of differentiation – both then
Divide on their own.
Fraternal – 2 or more eggs are
Released and fertilized.