Exam 1 Chapter 5: Vertebrate Development

Question 1

Describe steps of vertebrate development

Answer 1

Gamaete (male or female)
Fertilization(zygote)
cleavage
embryo (gastrulation/nerulation)

Question 2

What is yolk?

Answer 2

Yolk = food supply for developing embryo

Question 3

How does the animal pole of a zygote differ from the vegetal pole?

Answer 3

Animal pole
less yolky end of zygote

Vegetal pole
yolky end of zygote

Question 4

Amount of yolk

Question 5

Microlecithal eggs

Answer 5

Little yolk, young hatch quickly
Amphioxus, eutherian mammals

Question 6

Mesolecithal eggs

Answer 6

Intermediate yolk, young hatch later
Lampreys, amphibians

Question 7

Macrolecithal eggs

Answer 7

Lots of yolk, young hatch even later
Fishes, reptiles, birds, monotremes

Question 8

Holoblastic Cleavage (equal vs unequal)

Answer 8

Zygote divides completely
Equal: all cells the same size
Unequal: some cells smaller/larger

Question 9

Meroblastic cleavage (discoidal)

Answer 9

zygote does not divide completely, yolky region does not divide

Question 10

Define 3 types of egg envelopes

Answer 10

Primary: vitelline membrane (zona pellucida)
Secondary: follicle cells (corona radiata)
Tertiary: shell/egg case (sharks, rays)

Question 11

Understand diff in amount of yolks and cleavage in amphioxus compared to others

Answer 11

microlecithal egg, holoblastic equal cleavage

Question 12

Understand diff in amount of yolks and cleavage in amphibians compared to others

Answer 12

mesolecithal egg, holoblastic unequal cleavage

Question 13

Understand diff in amount of yolks and cleavage in birds/reptiles compared to others

Answer 13

macrolecithal egg, meroblastic cleavage

Question 14

Understand diff in amount of yolks and cleavage in eutherian mammals compared to others

Answer 14

microlecithal egg, holoblastic equal cleavage

Question 15

How do monotremes and marsupials differ from eutherians in these steps?

Answer 15

monotremes have a lot more yolk than others, marsupials have no morula stage (common in others); protoderm unique to marsupials

Question 16

Gastrulation

Answer 16

formation of germ layers
3 basic developmental tissue layers
ectoderm, mesoderm, endoderm

Question 17

Process of nerulation?

Answer 17

formation of central nervous system from ectoderm

Question 18

Gastrulation and nerulation in amphioxus

Answer 18

blastopore and coelom form how?

opening on hind end of gut, space inside indentation of gastrocoel forms the gut
blastocoel indents eventually make side connect to other

coelom will grown down around the gut body lined with mesoderm

Question 19

Why is dorsal lip in lamprey important?

Answer 19

It forms a new layer of dermis for the blastoderm that is needed

Question 20

Enterocoely

Answer 20

primitive method of coelom formation among chordates

Interior cavity is contained within the mesoderm when it first pinches off from other tissue layers

Question 21

Shizocoely

Answer 21

mesoderm forms first as a solid sheet and splits later to open the cavity within

Question 22

Describe development of blastodisc in sharks and teleost fishes

Answer 22

In sharks and teleost fishes, the blastodisc forms at the animal pole of the egg, where it undergoes meroblastic cleavage to develop into the embryo12. This process involves the blastodisc becoming the site of initial cell divisions, while the yolk remains largely undivided

Question 23

What is the improtance of the endomesoderm in sharks and teleost fishes?

Answer 23

The endomesoderm in sharks and teleost fishes is crucial for forming internal structures such as the gut, notochord, and mesodermal tissues

Question 24

Understand how the subdivisions of the mesoderm (epimere, mesomere, hypomere) form, and how the coelom forms from them in apmhibians

Answer 24

epimere makes omites
mesomore forsm urogenital system
hypomore forms lines
planchinic layer of hypoemere makes heart, lungs, pancreas, outer layer walls
coelem formed by splitting up mesoderm

Question 25

How is the basltodisc formed in birds and reptiles?

Answer 25

flat disc of cells, bilaminar (z-layers)

Question 26

Describe the function of the primitive node and streak in birds and reptiles?

Question 27

o How does the blastodisc transform from bilaminar (2 layers) to trilaminar (3 layers)?

Question 28

How does the notochordal process form?

Question 29

Understand the differences in gastrulation and nerulation in monotremes, marsupials, and eutherians

Question 30

Understand different types of tissues that form organs

Answer 30

• Epithelium
• Connective Tissue
  o Bone and cartilage: more later
• Muscle Tissue
  o More later