Chapter 17: Annelids, Clade: Clitellata, Class: Oligochaeta

Question 1

They live in what habitats?

Answer 1

• fresh water or soil, very few are parasitic or marine

Question 2

Nearly all of them bear what? But in fewer number than class polychaetes .

Answer 2

seta

Question 3

They burrow in _____ and usually live in ____. Often called?

Answer 3

• moist rich soil
• branched interconnected tunnels
• night crawlers

Question 4

What is food stored in?

Answer 4

• a thin walled crop

Question 5

What grinds food into small pieces?

Answer 5

• muscular gizzard

Question 6

Digestion and absorption occur where?

Answer 6

• intestine

Question 7

What increases the surface area for absorption?

Answer 7

• typhlosole

Question 8

What tissue surrounds the intestine and synthesizes glycogen and fat?

Answer 8

• Chloragogen

Question 9

What two things aid in the transportation of food, wastes and respiratory gases?

Answer 9

• coelomic fluid and blood

Question 10

What kind of system does the blood circulate in? With what five things running lengthwise in the body?

Answer 10

• closed circulatory system

- five main trunks

Question 11

The dorsal vessel contains ___ and functions as a ____.
It pumps blood ___ into five pairs of ___.
The _____ ensure steady pressure in ventral vessel.

Answer 11

• valves, true heart
• anteriorly, aortic arches
• aortic arches

Question 12

The ventral vessel serves as what? Delivering blood to body walls, nephridia, and digestive tract.

Answer 12

• aorta

Question 13

The blood contains colourless _____ and dissolved ___.

Answer 13

• ameboid cells

- hemoglobin

Question 14

There are ___ special gaseous exchange organs.

Answer 14

• no

Question 15

Gass exchange occurs where?

Answer 15

across the body surface

Question 16

In damp rainy weather they occupy where?

In dry weather?

Answer 16

• near the surface

- burrow deep underground and go dormant coiled in a slime chamber

Question 17

Peristaltic movements:

Step 1. Contractions of _______in the anterior end lengthen the body, pushing the anterior end forward where it anchors.

Answer 17

circular muscles

Question 18

Peristaltic Movements:

Step 2. Anchoring is accomplished by contraction of the _______ in forward segments.

Answer 18

longitudinal muscles

Question 19

Peristaltic Movements:

Step 3.Anchoring Causes the segments to become ___ and ____pushing against the burrow.

Answer 19

• short and wide

Question 20

Setae what are they? Function? GO

Answer 20

• bristle like rod set in a sac and moved by tiny muscles
• project outward through small pores in cuticle
• aid in anchoring by digging into walls of burrow

Question 21

What is their main method of getting a food source?

Answer 21

• scavenging

L> feeding on decaying organic matter, leaves, refuse etc

Question 22

Food is moistened by the ___ and drawn in by a sucking action of the _____.

Answer 22

• mouth

- muscular pharynx

Question 23

Calcium in soil leads to_____.

Answer 23

high blood Ca 2+

Question 24

What along the esophagus reduces calcium ion concentration in the blood?

Answer 24

• Calciferous glands

Question 25

Why is too much calcium ion bad?

Answer 25

- blood will crystallize and cause blockages

Question 26

Where are metanephridia located which aid in excretion?

Answer 26

there are a pair of metanephridia in each somite except the first three and terminal one

Question 27

The nervous system consists of what two things?

Answer 27

CNS and peripheral nerves

Question 28

A pair go cerebral ganglia connect around the ___ to the ganglia of the __.

Answer 28

- pharynx | - ventral nerve cord

Question 29

Fused ganglia in each somite contain both ___ and ___.

Answer 29

- sensory and motor fibers

Question 30

Neurosecretory cells in the brain and ganglia secrete ____.

Answer 30

- neurohormones wich regulate reproduction, secondary sex characteristics and regeneration

Question 31

One or more ____ located in ventral nerve cord increase the rate of ___ and stimulate _____ of many muscles in many segments.

Answer 31

- giant axons | - conduction, contractions

Question 32

General Behaviour: - They avoid right light which is called ? - What is important in locating food? - They have a limited learning ability which is?

Answer 32

- negative phototaxis - chemical stimuli - trial and error learning

Question 33

Reproduction and Development : - The sexes are not separate therefore they are classified as ? - In Lumbricus, reproductive structures are located in what somites? - Sperm is produced by ___ and matures in the ____ and pass into ___. - Eggs are discharged by __ into ____ and ciliated funnels transport them outside. - Two pairs of ____ receive and store sperm.

Answer 33

- monoecious - 9 through 15 - testes, seminal vesicles, sperm ducts - ovaries, coelomic cavity - seminal receptacles

Question 34

What time of the day and what kind of weather do they mate in?

Answer 34

- night during warm, moist weather

Question 35

Describe the Process of mating: - Aligning on opposite directions ___ surfaces together. - Mucus secreted by ___ holds the worms together. - Sperm from each worm are transported to the ____ of the other along ____. - After mutual copulation, each worm secretes a ___ and ___ to form a cocoon. - The cocoon passes forward and __, __ and __ are added. - Fertilization and embryogenesis occur in the __. - ____ will emerge from the cocoon.

Answer 35

- ventral - clitellum - seminal receptacles , seminal grooves - mucus tube, chitinous band - sperm, eggs and albumin - cocoon - young worms