EARTHWORM ( Annelids )

Question 1

Explain body structure (4)

Answer 1

1. Long segmented body covered with fine bristles that are retractable
2. 90-150 segments
3. Front segment modified for mouth, last segment for anus
4. longest earthworm in SA is 6.7 m

Question 2

What is anterior and posterior? (2)

Answer 2

ANTERIOR - front

POSTERIOR - back

Question 3

Explain the 2 ways the EARTHWORM moves ? (8)

Answer 3

1. Circular muscles: that make up the segments are used to lengthen earthworms body
2. Fine bristles that sticks out (protrude) from the front (anterior) segments anchors in soil while back (posterior) segments drag along. Then the bristles on the front (anterior) segments are pulled back and the bristles on the back (posterior) segments are anchored in the soil and push the front segments forward.

Question 4

Explain how an EARTHWORMS eats and it’s natural nutrition and how it has adapted? (6)

Answer 4

Front segment has membrane that covers mouth opening, helps to push food in mouth.

Earthworms naturally eats organic material:

plants, insect parts and bacteria

But they have adapted for use of compost making by eating:

anything that once lived like leftover food, newspaper, eggshells, meat, tea bags

Question 5

Explain EARTHWORMS respiration (4)

Answer 5

Through skin:

Oxygen dissolves on moist hide and absorbed through skin into the body tissue and transported to rest of body.

Question 6

Discuss why Water Balance is important for EARTHWORMS (2)

Answer 6

Always moist to prevent drying out

Moisture on hide dissolves gases for respiration (breathing)

They HAVE TO live in moist enviroments

Question 7

How does EARTHWORMS reproduce / multiply?

Answer 7

Earthworms are hermaphrodites

(both Male and Female)

The Clitellum (saddle like area) secreates slimy cocoon where eggs are fertilised during mating.

Clitellum is between 30 - 40 segment.

Juvenile (babies) hatch from cocoon

they look like earthworms

Question 8

What is Hermaphrodites ?

Answer 8

Annimal with Male and Female organs

Question 9

What is a Juvenile

Answer 9

Young animal - new born

Question 10

What senses are very sensitive/best with the EARTHWORM?

Answer 10

Sense of TOUCH

Highly developed to feel even as a bird land close by. They feel the vibrations in the ground and burrow deep into soil for protection.

Question 11

What senses are the worst with EARTHWORMS?

Answer 11

SIGHT

EARTHWORMS can’t see

Question 12

What role does EARTHWORMS play in our ecosystem?

Answer 12

• Decomposition of dead organic material
• Kill harmful bacteria and makes healthy bacteria through their urine and faeces.
• Responsible for healthy soil and plants
• They help loosening the soil to let oxygen into the soil for plant growth.

Question 13

EARTHWORM SKETCH

Answer 13