1
Q
- series of progressive changes in an individual from it’s beginning to maturity
- specialization occurs as a hierarchy of developmental “decisions”
A
Development
2
Q
- the theory that involves a tiny human in a sperm
A
Humoculus
3
Q
- Many eggs release a chemical molecule that attracts sperm of the same species to the egg
A
Contact and Recognition Between Egg and Sperm
4
Q
- Thin membrane above the egg plasma membrane
A
vitelline envelope
5
Q
- Fertilization cone forms where the sperm contacts the vitelline membrane
- Sperm head drawn in and fuses with egg plasma membrane
- Important changes in the egg surface block entrance to any additional sperm
A
Prevention of Polyspermy
6
Q
- the entry of more than one sperm
A
Polyspermy
7
Q
- used to block out other sperm
A
Fast block
8
Q
- the name for a fertilized egg
A
Zygote
9
Q
- embryo divides repeatedly
A
Cleavage
10
Q
- large cytoplasmic mass gets converted into small maneuverable cells
- No cell growth occurs, only subdivision until cells reach regular somatic cell size
A
Blastomeres
11
Q
- Zygote has been divided into many hundreds or thousands of cells
A
Blastula
12
Q
Cleavage Types
A
Holoblastic
Meroblastic
13
Q
- Cleavage extends entire length of egg
– Egg does not contain a lot of yolk, so cleavage occurs throughout egg
A
Holoblastic
14
Q
- cells divide at the top of the yolk
- too much yolk, can’t divide
A
Meroblastic
15
Q
Egg Types and Cleavage
A
Isolecithal
Mesolecithal
Telocithal
16
Q
– Very little yolk, evenly distibuted
– Use Holoblastic cleavage
A
Isolecithal
17
Q
– Moderate yolk
– Use Holoblastic
A
Mesolecithal
18
Q
– Have an abundance of yolk
– Use Meroblastic cleavage
A
Telocithal
19
Q
- cleavage creates a cluster of cells called the blastula
- During the blastula stage, the first germ layer forms
– Cells are arranged around a fluid-filled cavity called the blastocoel
A
Blastulation
20
Q
- Results in the formation of a second germ layer
- Involves an invagination of one side of blastula
– Forms a new internal cavity called the gastrocoel - creates an opening into the cavity: Blastopore
A
Gastrulation
21
Q
2 layers of the gastrula
A
Ectoderm and Endoderm
22
Q
- ## The only opening into embryonic gut
A
Blastopore
23
Q
- Some animals retain the blind gut
- the opening does not fully extend to other side
A
Flatworms, sea anemones
24
Q
- in which the opening extends and produces a second opening, the anus
A
Complete gut
25
- Animals with two germ layers
Diploblastic
26
- animals with 3 germ layers (most animals add a 3rd germ layer)
Triploblastic
27
- Forms between the endoderm and the ectoderm
- arises from endoderm
Mesoderm
28
- germ layer that deals with the epithelium and nervous system
Ectoderm
29
- germ layer that deals with epithelial lining of the digestive and respiratory
tract, liver, pancreas,
Endoderm
30
- Muscular system, reproductive system, bone, kidneys, blood
Mesoderm
31
- Body cavity surrounded by mesoderm
Coelom
32
– The method by which the coelom forms is an inherited character
• Important in grouping organisms based on developmental characters
– Upon completion
• Body has 3 tissue layers and 2 cavities
- coelom formation
33
- Animals Without a Coelom are called
Acoelomates
34
- Two major groups of triploblastic animals
Protostomes and Dueterostomes
35
- blastopore develops into an anus first, and the second opening becomes a mouth
Deuterostome embryos
36
- blastopore becomes a mouth first, then the second opening becomes an anus
Protosome embryos
37
- Coelom Formation - mesoderm movement
enterocoely and schizocoely
38
- Mesoderm sides push outward and expand into a pouch-like coelomic compartment
• Pouch-like compartment pinches off and forms a mesoderm bound space
surrounding the gut
• Occurs in Deuterostomes
Enterocoely
39
- Endodermal cells move to blastopore and develop into mesoderm
• Mesoderm separates or splits to form cavity (coelom)
• Occurs in Protostome
Schizocoely
40
- mesoderm fills the blastocoel
Acoelomate plan
41
- mesoderm lines one side of the blastocoel
- pseudocoelomate plan
42
- band of mesoderm surrounds the gut and spits open
Schizocoelous plan
43
- mesodermal pouches surround the gut
Enterocoelous plan
44
- mesodermal pouches surround the gut
Enterocoelous plan
45
– All vertebrate embryos share chordate hallmarks
The Common Vertebrate Heritage
46
•Dorsal neural tube
•Notochord
• Pharyngeal gill pouches with aortic arches
• Ventral heart
• Postanal tail
Common vertebrate heritage
47
- embryos develop within the amnion
Amniote
48
- Fluid-filled sac that encloses the embryo
– Provides an aqueous environment in which the embryo floats
– Protection from mechanical shock
- contains 4 extraembryonic membranes including the amnion
Amniotic egg
49
- responsible for storing yolk
Yolk sac
50
• Storage of metabolic wastes during
development
• Respiratory surface for gas exchange
Allantois
51
• Lies beneath the eggshell
• Encloses the embryo and other extraembryonic membrane
Chorion
52
–Need for oxygen increases
–Allantois and chorion fuse to form a
respiratory surface, the chorioallantoic
membrane
Happens when the embryo is growing
53
– Most mammalian embryos do not develop within
an egg shell
- Develop within the mother’s body
- Most retained in the mother’s body
Mammalian Placenta
54
• Primitive mammals that lay eggs
• Large yolky eggs resembling bird eggs
•Duck-billed platypus and spiny anteater
Monotremes
55
– Embryos born at an early stage of development and
– Continue development in abdominal pouch of mother
Marsupials
56
– Represent 94% of the class Mammalia
– Evolution of the placenta
• Required reconstruction of extraembryonic membranes
• Modification of oviduct
– Expanded region formed a uterus
Placental Mammals
57
- Remains unchanged
- Surrounds embryo
- Secretes fluid in which embryo floats
Amnion
58
- Contains no yolk
- Source of stem cells that give rise to blood and lymphoid cells
- Stem cells migrate into the developing embryo
Yolk sac
59
- Contains no yolk
- Source of stem cells that give rise to blood and lymphoid cells
- Stem cells migrate into the developing embryo
Yolk sac
60
- Not needed to store wastes
- Contributes to the formation of the umbilical cord
Allantois
61
- Not needed to store wastes
- Contributes to the formation of the umbilical cord
Allantois
62
- forms most of the placenta
Chorion
Vzoo Lesson 1-4
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Decks in class (5)
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