Invertebraes (1)

Question 1

Define animals.

Answer 1

Animals:

-are eukaryotes,
-are multicellular heterotrophs
-have cells that lack cell walls.
-Animals also use ingestion, the eating of food

Question 2

How can animals be classified based on embryonic development?

Answer 2

In protostomes, the first opening in the embryo becomes the mouth.

In deuterostomes, the first opening in the embryo becomes the anus, and the mouth develops later.

Question 3

How can animals be classified based on body layers?

Answer 3

Two layers: outer ectoderm and inner endoderm

Three layers: endoderm, mesoderm, and ectoderm

Question 4

What are Eumetazoa and Bilateria?

Answer 4

Eumetazoa (“true animals”) diverges animals with tissues.

Bilateria describes Animals with bilateral symmetry

Question 5

What are lophotrochozoa, Ecdysozoans, and deuterostomia?

Answer 5

Lophotrochozoa phyla is based on genetic similarities

Ecdysozoans have external skeletons that must be shed for the animal to grow(ecdysis)

Deuterostomia includes all animals that undergo deuterostome development.

Question 6

Explain the morphological features of sponges.

Answer 6

1. Do not have true tissues
2. Lack of body symmetry
3. Usually marine, although some are found in freshwater.
4. Their flagellated choanocytes filter food from water passing through pores in the body

Question 7

What is the simplest and earliest animal?

Answer 7

Sponges.

Question 8

What phylum do sponges belong to?

Answer 8

Porifera.

Question 9

What kind of feeders are sponges?

Answer 9

Sponges are suspension feeders, collect food particles from water passed through some type of food-trapping equipment.

Choanocytes collect food particles suspended in the water that streams through their porous bodies.

Question 10

What kind of defense mechanism do sponges have and why?

Answer 10

Adult sponges are sessile, meaning they are anchored in place and they cannot escape from predators.

Adapted to produce defensive compounds such as toxins and antibiotics that deter pathogens, parasites, and predators.

Question 11

What are the characteristics of Cnidarians?

Answer 11

(starfish& sea anemone)
-Characterized by radial symmetry
-Have two true tissue layers,
-Have a gastrovascular cavity(type of digestive tract with only one opening meaning their mouth and anus are one)

Question 12

What are the two forms of Cnidaria?

Answer 12

Polyp (such as hydras)
Medusa (such as jellies).

Question 13

What is the defense system in Cnidarians?

Answer 13

Unique stinging cells, called cnidocytes(can coil and uncoil), that function in defense and in capturing prey.

Each cnidocyte contains a fine thread coiled within a capsule

When discharged, the thread can sting or entangle prey. Some large marine cnidarians use their stinging threads to catch fish.

Question 14

What are the characteristics of Flatworms and what phylum do they belong to?

Answer 14

-Platyhelminthes.

Bilateral animals with no body cavity.
-A planarian has a gastrovascular cavity
-A simple nervous system.

Flatworms live in marine, freshwater, and damp terrestrial habitats

Question 15

What phylum do flatworms belong to?

Answer 15

Platyhelminthes.

Question 16

What are the simplest bilateral animals?

Answer 16

Flatworms.

Question 17

What are the characteristics of Nemotodes?

Answer 17

(roundworms,ascaris)

-Bilateral symmetry,
-Three tissue layers,
-A nonliving protective cuticle(to help retain water) that is shed periodically
-A complete digestive tract with a mouth and anus.

Question 18

What kind of animals are nemotodes?

Answer 18

Some nematodes are free-living decomposers, while others are plant or animal parasites.

Question 19

What are the characteristics of Molluscs?

Answer 19

-A muscular foot, which functions in locomotion
-A visceral mass containing most of the internal organs.
-A mantle, which may secrete a shell that encloses the visceral mass, and a circulatory system.

Question 20

How do Molluscs feed?

Answer 20

Many molluscs feed with a rasping radula (spiky tongue), used to scrape up food.

Question 21

What are the morphological features of Annelids?

Answer 21

(Earthworms)
1. Segmentation, the subdivision of the body along its length into a series of repeated parts,(two kidneys, two lungs etc)a nervous system

2. A closed circulatory system in which blood remains enclosed in vessels throughout the body.

Question 22

What kind of circulatory system do Molluscs and arthropods have?

Answer 22

Molluscs and arthropods, have an open circulatory system in which blood is pumped through vessels into open body cavities.

Question 23

What are the 2 clades of Annelids?

Answer 23

The two major clades of annelids are:-

-Errantians (mostly mobile marine worms)

-Sedentarians (less mobile worms, including earthworms, leeches, and many tube-dwellers).

Question 24

What are the morpholigcal features of arthropods?

Answer 24

1. Their diversity and success are due to their segmentation, hard exoskeleton, and jointed appendages.
2. As an arthropod grows, it must periodically shed its old exoskeleton and secrete a larger one, a complex process called molting, or ecdysis.,