Exam 3a

Question 1

How do we Define animals?

Answer 1

1. Multicellular
2. heterotrophs (cannot produce food on their own)
3. Mobile at some stage of their life

Question 2

What is Cambian explosion?

Answer 2

Sudden explosion of animals coming into existence.

Question 3

Why is Cambian explosion a problem to darwin?

Answer 3

Evolution takes time and changes species over time. cambian explosion just happens all at once spontaneously

Question 4

How do scientists explain the cambian explosion?

Answer 4

Hox Genes.

Question 5

What are Hox Genes?

Answer 5

They are conductor genes. The are major genes that control developement of other genes. You dont need too many genes to change form.

Question 6

what is Asymmetrical body plane?

Answer 6

Organisms who dont have a top, bottom,left, or right.

Ex: Bacteria

Question 7

What is Radially symmetrical body plane?

Answer 7

It has a top and bottom. It has many planes and every plane that goes through the center will break the image into 2 halves that are mirror images.

Question 8

What is Bilaterally symmetrical body plane?

Answer 8

Only One plane can cut an organism into 2 halves that are mirror images.

Question 9

What is so important about body planes?

Answer 9

Shape of organisms will affect their lifestyle. Ex: bilaterally symmetrical organisms will have a different lifestyle than a radially symmetrical organism

Question 10

What is Diploblastic?

Answer 10

Two Embryonic layers

They only have the ectoderm and endoderm.

Question 11

What is Triploblastic?

Answer 11

Three embryonic layers

They have a ectoderm mesoderm and endoderm

Question 12

What is a protostome?

Answer 12

Mouth develops first before anus. Came from spiral cleavage

They are Arthropods, mollusks, sgemented worms

Question 13

What is a deuterostome and example phylum?

Answer 13

Anus develops first before mouth came from radial cleavage

They are choridaters and echinoderms

Question 14

What is the ectoderm and what does it give rise to?

Answer 14

its the germ layer covering the surface of the embryo, giving rise to the outer covering of the animal

Question 15

What is the Endoderm and what does it give rise to?

Answer 15

the innermost germ layer that gives rise to teh lining of the digestive tract and organs such as the liver and lungs in vertebrates

Question 16

What animals are diploblastic?

Answer 16

cnidarians (jelly fish)

Question 17

What is a mesoderm and what does it give rise to?

Answer 17

a germ layer that fills much of the space between the ectoderm and endoderm. it gives rise to the muscles and most organs between the digestive tract.

Question 18

What animals are triploblastic?

Answer 18

Flatworms,
arthropods
vertebrates

Question 19

What is a coelom and give an example animal

Answer 19

A body cavity. its a fluid- or air-filled space located between the digestive tract and the outer body wall.
Earthworms have coelem.

Question 20

what does a true coelom form?

Answer 20

it forms from tissues derived from mesoderm.

Question 21

What do you call animals with true coelom?

Answer 21

coelomates

Question 22

What is a pseudocoelom and give an example animal?

Answer 22

a body cavity that is formed from mesoderm and endo derm. It is NOT a false body cavity.
Roundworms have it

Question 23

What is acoelomate?

Answer 23

lacking of a body cavity. Planarians have it.

Question 24

What is a hydroskeleton who has it?

Answer 24

internal body fluids in limited spaced . round worms have it

Question 25

What is exoskeleton and who has it?

Answer 25

rigid external body parts like shells or armor plates. Snails and clams have it

Question 26

What is endoskeleton?

Answer 26

skeleton fond within the body structures (we have it )