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Flashcards in Diversity of Animals I Deck (266)
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1

What is the phylum name for flatworms?

Platyhelminthes

2

How many germ layers do platyhelminthes have?

Triploblastic

3

What type of body cavity do platyhelminthes have?

Acoelomates

4

Describe the body cavity of platyhelminthes

Filled with loose parenchyma derived from mesoderm

5

Describe the symmetry of platyhelminthes

Bilateral symmetry

6

What is a characteristic of the platyhelminthes body shape?

Dorsoventrally flattened

7

What are three classes of platyhelminthes?

1. Turbellaria
2. Trematoda
3. Cestoda

8

Are turbellaria free-living or parasitic?

Free-living

9

What structure do turbellaria use to feed?

A pharynx that comes out of a ventrally-located mouth

10

Describe the turbellaria diet

Carnivorous: living invertebrates or dead animals

11

What is an advancement of turbellaria digestive system?

Highly branched to increase surface area

12

Do platyhelminthes have a complete digestive tract?

No, they do not have an anus.

13

How does egestion occur for platyhelminthes?

Out of mouth (no anus)

14

Where does platyhelminthes gas exchange occur?

Diffusion through their skin (aided by being flat)

15

How does excreton occur for platyhelminthes?

Excretion of NH3 by diffusion

16

What is a huge advancement of platyhelminthes for water removal?

Water is removed by protonephridia with a flame cell.

17

Describe the platyhelminthes central nervous system

Transverse nerve cords with a tiny cerebral ganglia at the head of the animal.

18

How do turbellaria reproduce asexually?

Transverse binary fission into 2 small turbellarians called zooids.

19

How do turbellaria reproduce sexually? (3 steps)

1. Both flatworms exchange sperm (monoecious)
2. Zygotes are enclosed in a cocoon
3. Zygotes develop into immature turbellarians that break out of the cocoon when the weather is good.

20

What is a common name for the trematoda?

Flukes

21

How do trematodes feed?

Adult flukes are parasitic on vertebrates

22

Describe the trematoda digestive tract (2 components)

1. Mouth and Pharynx
2. 2 Intestinal branches

23

Do trematodes have a complete digestive system?

No. No anus

24

How does a fluke protect itself from the host's defenses and digestive juices?

A layer of the epidermic called the tegument

25

Is the fluke tegument living or nonliving?

Living

26

Where does gas exchange occur in a trematode?

Diffusion through epidermis

27

Where does excretion occur in a trematode?

Diffusion of NH3 through epidermis

28

How does a fluke attach itself to its host? (2 ways)

1. Oral sucker
2. Acetabulum (ventral sucker)

29

What species of trematode is the human liver fluke?

Clonorchis sinensis

30

Describe the eight (8) step life cycle of the human liver fluke

1. Fluke eggs shed in feces of infected people and are washed into fresh water
2. Fluke larva (miracidium) emerges from egg and ingested by snail
3. Miracidium loses cilia to become a sporocyst
4. Sporocyst grows into a redia that can reproduce asexually.
5. Redia reproduces forming more rediae.
6. Snail deteriorates and rediae grow tails to become cercaria.
7. The cercaria attaches to fish using tail, loses tail and encysts to form a metacercaria.
8. Humans eat raw fish and digestive juices release metacercaria which grows into sexually reproduce adult.