V2 Common Characteristics of Vertebrates

Question 1

Blastula

Answer 1

Fluid filled ball- when the zygote is dividing, during cleavage, it forms a ball of cells.

Question 2

Animal Pole

Answer 2

Smaller cells gathered at the top of the blastula.

Question 3

Vegetal Pole

Answer 3

Larger cells at the bottom contain more yolk (which are nutrients provided by the ovary fats, proteins and carbohydrates).

Question 4

Unspecialized cells are called _____________?

Answer 4

Totipotent

Question 5

Gastrulation

Answer 5

The process of the cells in a blastula moving inwards at the blastopore to form a gastrula of 3 layers

Question 6

The ENDOderm is ________ and specializes to become

Answer 6

The inside layer and becomes the gut lining and derivatives (liver, intestines, stomach) which makes sense because that is the part of the blastula with all of the nutrients (yolk)

Question 7

The ECTOderm is ________ and specializes to become

Answer 7

The outside layer and becomes the nervous system and outside layer of the skin.
Neurectoderm forms the nervous system.

Question 8

The MESOderm is ________ and specializes to become

Answer 8

The middle layer and becomes everything else (blood vessels, muscles and bones).

Question 9

Deuterostome

Answer 9

“Second” “mouth” refers to the fact that the mouth forms secondarily during embryogenesis. The first opening that is formed in the embryo is the anus.

Question 10

Animal Pole forms what?

Answer 10

The back of the vertebrate.

Question 11

Vegetal Pole forms what?

Answer 11

The abdomen of the vertebrate.

Question 12

Are cells still totipotent at this phase? Explain.

Answer 12

Yes, cells are still unspecialized in that they can be induced to restart development and have the potential to create an entire organism. However, their “fates are now determined” by virtue of where they ended up on the blastula, so what they are going to become on the adult organism is now determined.

Question 13

Neurulation

Answer 13

The process of the nervous system developing.
START

1) aggregation of mesoderm cells into a rod-like structure to form the notochord for the main axis of structural support in the organism
2) notochord development induces invagination- the dorsal ectoderm folds on itself, moving towards each other and pinching off the top, forming the dorsal neural tube (which will form the CNS)
3) Neural crest cells develop (stray cells form between the neural tube and the overlying ectoderm) These cells will migrate through the embryo and become distinct components of the nervous system in vertebrate specifically. Example: neural crest cells will become part of the sense organs in the adult organism.

Question 14

Notochord

Answer 14

Is the structural spine (think the backbone of the spine).

Question 15

Neural Tube

Answer 15

The spinal chord

Question 16

Induction

Answer 16

Notochord formation induces the folding of the ectoderm. Chemical signals get sent from the notochord to the overlying ectoderm that induce the ectoderm to start folding over, so the development of the notochord is a very important step for the rest of the development to occur.

Question 17

Blastopore

Answer 17

Spot where the walls of the mesoderm pinches off- forms the anus

Question 18

Somites

Answer 18

The mesoderm flanking the notochord starts to form segments which will eventually develop into the skeleton so the vertebrate and skeletal muscles. Anything that is segmented in the adult form is derived from somites.

Question 19

Nephrotomes

Answer 19

Found underneath the somites in the embryo and develop into the adult kidney.

Question 20

Pharyngeal pouches

Answer 20

Formed in a similar way to invagination in neuralation (endoderm cells move to the outside and ectoderm cells move to the inside).

Develops into pharyngeal slits/ gills/ thyroid gland in adults.

Question 21

Neural tube development in the anterior region

Answer 21

Brain differentiates into 3 lobes:

• hind brain
• mid brain
• fore brain

But hind and fore brain differentiate into 2 lobes each which gives a total of 5 lobes in the organism.

Question 22

Ectodermal placodes

Answer 22

Thickening of the nervous system in the ectoderm at sense organs (eye placode, ear placode and nostrils)

Question 23

What is the final product of neurulation?

Answer 23

The neurula or the phyryngula

It looks the same in most organisms weather you are frog or human!

Question 24

Organogenesis

Answer 24

Longest stage (can take up to 22 months in elephants)

Specialization of embryonic cells to form organs and organ systems.

Differential cell division, cell growth and cell death all occur to give rise to different body shapes.

Question 25

Integument (skin) system provides 5 things:

Answer 25

1) protection of diseases and temperatures
2) communication sending and receiving through signals (colour change during breeding season or pheromones)
3) respiration through diffusion (excrete CO2 and take in O2)
4) excretion of nitrogenous wastes (in fish)
5) osmoregulation allows to take in water or salts if needed

Question 26

Epidermis dead or alive?

Answer 26

In most vertebrates alive

In amniotes dead

Question 27

Fibroblasts

Answer 27

Cells that lay down the collagen fibres

Question 28

Dermis

Answer 28

Thick layer underneath the epidermis primarily elastic collagen derived from the mesoderm

Question 29

Epidermis

Answer 29

Originates from the ectoderm

Layer of cells on the outside

Question 30

Melanophore

Answer 30

Pigment cells in all vertebrates that contain melanin and allow for camouflage and chromatophore colour changing

Question 31

What is missing in the integumentary system that we looked at that gnathostomes have?

Answer 31

In cartilaginous fish (sharks): denticles with sensory nerves and blood vessels like teeth

In teleost fishes (ray finned and lobe finned fish):
scales overtop of the epidermis made of dermal bone

Question 32

Skeletal system provides what 3 things:

Answer 32

1) support in the vertebrate backbone
2) protection of the brain with the skull and internal organs
3) facilitates movement

Question 33

In lamprey where is there skeletal support around the gills?

Answer 33

Gill pouches are internal supports present to hold gills up and keep them suspended in the water for gas exchange

Question 34

Endochondral

Answer 34

Inside + cartilage

Bone that is layed down in cartilage usually in long bones (ribs).

Question 35

Dermal bone

Answer 35

Laid down in the dermis, so in the integument by the dermis

Question 36

Osteocyte

Answer 36

Bone cells are found within lacunae and joined up through canals within bone

Question 37

Skeleton of fishes

Answer 37

Because of buoyancy in water, bones in fish are mainly axial to support the cranium neural tube along the longitudinal axis of the body.

Question 38

Skeleton in tetrapods

Answer 38

Movement on land forced adaptation to bone. Specializations in the invertebral disks connecting to adjoining vertebrate facilitated movement.

• cartilage became bone in the ribs
• appendages elongated