second block

Question 1

stages of amphibian development

Answer 1

1. cleavage - meroblastic cleavage
2. Blastulation - blastula -> individual cells are blastomeres, cavity is blastocoel
3. gastrulation - blastopore -> yolk plug -> new cavity forms called archenteron, ectoderm outside, endoderm inside, mesoderm in between
4. neurulation - neural plate forms -> neural ridges -> neural groove -> neural tube (brain and spinal cord) -> notochord

Question 3

chicken development

Answer 3

early embryo
1. primitive streak
2. mesodermal tissues
3. notochord development
chick at 24 hours
1. neural plate -> neural folds -> neural groove
2. neural tube -> anterior end becomes the brain, posterior end becomes the spinal/nerve cord
chick at 48 hours
1. beating heart -> blood through vitelline blood vessels
2. brain, eyes, spinal cord
3. somites

Question 4

what are the five events of development?

Answer 4

1) fertilization
2) cleavage
3) gastrulation
4) neurulation
5) organogenesis

Question 7

stages of echinoderm development

Answer 7

1. unfertilized egg
2. fertilized egg
3. early cleavage - holoblastic
4. late cleavage - blastocoel -> blastula -> blastomeres
5. early gastrulation - blastula -> gastrula, germ layers
6. middle gastrulation
7. late gastrulation- fusion

Question 8

what cell stage is a morula?

Answer 8

8-16

Question 10

what comes after morula?

Answer 10

blastula and then gastrula

Question 11

three biological processes of development

Answer 11

cell division, differentiation, morphogenesis

Question 12

What are the four basic characteristics common to chordates during their development?

Answer 12

1. notochord
2. dorsal hollow nerve cord
3. pharyngeal slits
4. postanal tail

Question 13

How do the invertebrate chordates differ from the vertebrate chordates?

Answer 13

invertebrates do not have backbones or skulls

Question 14

How do amniote chordates differ from non-amniote chordates?

Answer 14

non amniote chordates eggs lack a shall and the four extra embryonic membranes

Question 15

What are the three types of embryological tissue layers found in most animals?

Answer 15

1. ectoderm
2. endoderm
3. mesoderm

Question 16

What occurs in each of these embryological developmental phases: cleavage, gastrulation, neurulation, and organogenesis?

Answer 16

cleavage- cell begins to split. produces multicellular morula and blastula
gastrulation- formation of the gastrula consisting of the three germ layers
neurulation- formation of the nervous system in chordates
organogenesis- development of organs from the three germ layers

Question 17

Discuss the effects of large amounts of yolk on the events of early development.

Answer 17

large amounts of yolk result in uneven cleavages. the animal pole will end up with more cleavages than in the vegetal pole

Question 18

Relate the events of early development in vertebrates to the formation of a dorsal nerve cord.

Answer 18

during neurulation, a raised sheet of cells from the neural plate -> neural ridges -> neural tube -> notochord

Question 19

List the events in early development that are common to all organisms

Answer 19

1. cell division
2. differentiation
3. morphogenesis