Invert Development

Question 1

Define Metazoan

Answer 1

Any animal that undergoes development from an embryo stage with three tissue layers, namely the ectoderm, mesoderm, and endoderm. Any animal that is multicellular.

Question 2

Name the 7 typical features of metazoan development

Answer 2

1. Fertilization
2. Cleavage
3. Gastrulation
4. Differentiation
5. Organogenesis
6. Morphogenesis
7. Growth and Sexual Maturation

Question 3

Define Fertilization and name the product of it

Answer 3

New individuals created from the fusion of two gametes. Product is a Zygote

Question 4

Define Cleavage and name the product of it

Answer 4

Zygote undergoes rapid mitotic division. Cytoplasm divided into many smaller cells (Blastomeres)

Question 5

Define Morula

Answer 5

Cluster of Blastomeres

Question 6

Define Blastula

Answer 6

Hollow ball of cells with central cavity

Question 7

Define Gastrulation and name the 3 products of it

Answer 7

Cells of blastula undergo rearrangement into the 3 Germ Layers:

1. Endoderm: Inside embryo
2. Ectoderm: Surface of embryo
3. Mesoderm: between endo and ectoderm

Question 8

Define Differentation

Answer 8

Cells in different germ layers giving rise to distinctive types of tissues

Question 9

Into what 2 things does the Ectoderm differentiate?

Answer 9

1. Most of nervous system
2. Surface of skin

Question 10

Into what does the Endoderm differentiate?

Answer 10

Epithelial lining and associate organs

Question 11

Into what 4 things does the Mesoderm differentiate?

Answer 11

1. Muscle
2. Blood
3. Bone
4. Connective Tissues

Question 12

Define Organogenesis

Answer 12

Cells from the same and differnt germ layers interact and rearrange to produce organs

Question 13

Define Morphogenesis

Answer 13

Aquisition of form/shape; typically coincides with organogenesis

Question 14

Define growth and Sexual Maturation as they relate to Metazoan development

Answer 14

Organism grows in size via Mitosis until it reaches sexual maturity and initiates Gametogenesis

Question 15

Define Gametogenesis

Answer 15

Gametes are produced by Germ Cells

Question 16

Define the Germ line/Germ cells

Answer 16

Special cells set aside early during development that produce gametes

Question 17

Define Somatic Cells

Answer 17

All cells that are not germ cells

Question 18

Name 6 approaches to understanding development

Answer 18

1. Observation
2. experimental manipulation
3. genetics
4. molecular biology
5. biochemistry
6. ohylogenetic comparisons

Question 19

What is development? (super basic definition)

Answer 19

Change in phenotype over time

Question 20

What determines phenotype? (super basic answer)

Answer 20

Gene activity

Question 21

Name the 4 steps of the gene centered approach

Answer 21

1. Identify all genes
2. Determine what activites (i.e. functions) each gene has
3. figure out when and where each gene is active
4. figure out how the activites of each gene are regulated

Question 22

Draw a basic diagram of the C. elegans life cycle

Answer 22

Question 23

Draw basic diagram of C. elegans hermaphrodite form

Answer 23

Question 24

Draw basic diagram of C. elegans male

Answer 24

Question 25

Name the physical differences between the c. elegans genders (7 for both)

Answer 25

Females have:

1. Two-armed gonad
2. Vulva
3. Spermatheca
4. Anus
5. Intestine
6. Oocyte
7. Whip

Males have:

1. One-armed gonad
2. Sperm
3. Vas deferens
4. Cloaca
5. Fan
6. Ray
7. spicules

Question 26

Describe the difference in reproductive capabiltiy between the C. elegans genders

Answer 26

• The Hermaphrodite is Self-fertile: Germ line makes sperm and oocytes
• Male is Cross-fertile: only makes sperm

Question 27

name the 5 basic behaviors of C. elegans

Answer 27

1. Locomotion
2. Feeding
3. mating
4. defecation
5. egg laying

Question 28

Name the 4 basic senses of C. elegans

Answer 28

1. Smell
2. Taste
3. Sense touch
4. Thermosensation

Question 29

Why is meant by the phrase “C. elegans development is essentially invariant”? why is this helpful?

Answer 29

It means that the cells in hermaphroditic C. elegans individuals are produced in an indential pattern of cell divisions between individuals.

This invariant cell lineage makes is possivle to identify all of the cells in an individual and compare them across organisms.