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Honors Biology
Do Now Download Development Honors Notes
off of my website
Where’s my money?!?!?!
Hand in Meiosis Pictures Lab
Honors Biology
Something to think about as your open up your notes
Humans have approx. 50-75 trillion cells and these cells are all different types (hair, skin, liver, stomach cells, etc.).
How can you explain all these types of cells if humans only start as a single cell?
Honors Biology
IMPORTANT! RECOMBINATION Sperm = DNA (haploid) : one version of
each type of chromosome. Egg = DNA (haploid): same as above The combination of one sperm with one egg
will unite and make . If another sperm or another egg unite, a
human would result.
Honors Biology
Oogenesis
Meiosis 1 completedduring egg maturation
Meiosis 2 completedtriggered by fertilization
ovulation
Unequal meiotic divisions unequal distribution
of cytoplasm egg polar bodies
What is theadvantage of
this development system?
Put all your eggin one basket!
Honors Biology
1) Cleavage Repeated of zygote
1st step to becoming cellular unequal divisions establishes body plan
different cells receive different portions of egg cytoplasm & therefore different regulatory signals
Honors Biology
Cleavage zygote m b
establishes future development
zygote
blastulamorula
gastrulation
Honors Biology
Establish 3 cell layers E
outer body tissues skin, nails, teeth nerves, eyes, lining of mouth
M middle tissues
blood & lymph, bone & notochord, muscle
excretory & reproductive systems E
inner lining digestive system lining of respiratory, excretory &
reproductive systems
2) Gastrulation
ectoderm
mesoderm
endoderm
protostome vs. deuterostome
gastrulation inprimitive chordates
Honors Biology
Testing…In a study of the development of frogs, groups of cells in the germ layers of several embryos in the early gastrula stage were stained with five different dyes that do not harm living tissue. After organogenesis (organ formation), the location of the dyes was noted, as shown in the table below.
Tissue StainBrain RedNotochord YellowLiver GreenLens of the eye BlueLining of the digestive tract Purple
Honors Biology
Neurulation Formation of notochord & neural tube
develop into system
Notochord
Neural tube
develops intovertebral column
develops into CNS (brain & spinal cord)
Honors Biology
Growth and DifferentiationUmbilical blood vessels
Chorion
Amnion
Yolksac
AllantoisFetal blood vessels
Maternal blood vessels
Bird embryo
Mammalian embryo
Placenta
Honors Biology
Testing…All of the following correctly describe the fate of the embryonic layers of a vertebrate EXCEPT
A. neural tube and epidermis develop from ectoderm
B. linings of digestive organs and lungs develop from
endoderm
C. notochord and kidneys develop from endoderm
D. skeletal muscles and heart develop from mesoderm
E. reproductive organs and blood vessels develop from
mesoderm
Honors Biology
3. Growth and Differentiation As embryo develops, the # of cells continues
to
Differentiation cells become
Different sections of DNA are , some are turned .
Certain cells act as organizers These cells influence other cells to become
certain cells, tissues
Honors Biology
STEM CELLS Omnipotent = have the potential to be
type of cell. If mitosis is done, all cells are
identical. FACT: all of your cells contain the
(because of mitosis)
Honors Biology
Differentiation: some DNA is turned off and only some directions are read, for example: Skin cells: all
DNA directions are turned off, except for how to make skin.
HOW DO WE GET DIFFERENT CELLS?
Honors Biology
1. Placental Mammals Placenta - part of the wall of the uterus
Site of !!!!!!!!!!!!!!!!!!!!!!!!
Embryo’s and mother’s circulatory system are touching BUT NOT
Honors Biology
Umbilical cord Contains that the embryo will
get nourishment and oxygen from the mother’s blood to the
Honors Biology
Human fetal development The fetus just spends much of the 2nd & 3rd
trimesters just growing …and doing various flip-turns & kicks inside amniotic fluid
Week 20
Honors Biology
Human fetal development 24 weeks (6 months; 2nd trimester)
fetus is covered with fine, downy hair called lanugo. Its skin is protected by a waxy material called vernix
Honors Biology
Getting crowded in there!! 32 weeks (8 months)
The fetus sleeps 90-95% of the day & sometimes experiences REM sleep, an indication of dreaming
Honors Biology
2. Nonplacental Mammals mammals
Duckbilled platypus Anteaters
mammals Embryo begins to
develop in uterus Crawls into mother’s pouch Finishes developing in pouch Kangaroo, opossum
Honors Biology
A
1) Albumen –
A
2) Allantois –
A
3) Amnion –
Y
4) Yolk –
S
5) Shell – Calcium carbonate,
E