Invertebrates 4

Question 1

What group includes the annelids, rotifers, mollusks and flatworms

Answer 1

Lophotrocozoa

Question 2

What is special about the lophotrocozoa?

Answer 2

-Trocophore larvae
-Lophophore feeding structure(ring of tentacles around the mouth)

Question 3

What is an annelid?

Answer 3

-Ringed worm
-Segmented body
-True coelom
- Hydrostatic skeleton

Question 4

What is segmentation?

Answer 4

-The division of an organisms body plan into repetitive segments.
-Most segments have similar organizations and organs
-Segments are not always identical to accommodate specialization of organs
-Segments close together are very similar

Question 5

Advantages of Segmentation? (4)

Answer 5

1. Provides multiple copies of important organs and structures
2. Efficient nervous control( One ganglion and nerve in each segment means that the nervous response in each segment is very rapid/efficient and leads to efficient localized movement)
3. Increases body size by unit repetition
4. Regeneration(annelids can regrow segments that break off)

Question 6

Is segmentation unique to annelids? If not, name an example of segmentation in a different species?

Answer 6

No it is not. Segmentation also developed in vertebrates as our spring and rib cage

Question 7

Explain the annelid nervous system?

Answer 7

• Brain and ganglia (the more motile the annelid the more complex the brain/ganglia)
  -Brain connected to the ventral nerve cord
  -Each segment contains a ganglia

Question 8

Explain the annelid respiration system?

Answer 8

-Respiration occurs through the skin/gills

Question 9

Excretory system of the annelid?

Answer 9

-Annelids have tubular nephridia(equivalent to kidneys in humans) that get rid of waste

Question 10

Digestive system in annelids?

Answer 10

-Complete digestive system (one way tract with a mouth and anus)
-Distinct regions(oesophagus, intestines, crop(stores food in esophagus))

Question 11

Circulatory system in annelids?

Answer 11

-Closed system(blood is always contained within vessels)
-Blood is pumped throughout the organism through aortic arches(similar to hearts)

Question 12

Advantages of a closed circulatory system?

Answer 12

• Faster transport of gasses and nutrients
  -Better gas exchange between deep tissues and O2/CO2
  -Organism body can be thicker as they don’t need to undergo diffusion to exchange gasses

Question 13

What are the heart structures in annelids?

Answer 13

Aortic arches

Question 14

Trocophore larvae

Answer 14

Free-living and swimming larvae

Question 15

What is parapodia? What type of annelid does not have parapodia?

Answer 15

Parapodia: the locomotory organ of a segmented annelid.
Oligochaete do not have a parapodia

Question 16

What is a Polychaete?

Answer 16

-Detritivores(feed on dead/decomposing matter)
-Filter-feeder strain organic matter from water
-Separate sexes with external fertilization(trochophore larvae)

Question 17

3 Characteristics of mollusks?

Answer 17

-Triploblastic
-Bilaterally symmetrical
- Trocophore Larvae

Question 18

3 regions of the mollusk body plan?

Answer 18

Foot: large muscle used for movement
Visceral Mass: Contains main organs(heart, nephridia, stomach)
Mantle: Outgrow of the body wall that encloses the visceral mass

Question 19

Define Nephridia

Answer 19

An invertebrate organ which occurs in pairs and removes wastes similar to kidneys.

Question 20

Do mollusks have closed or open circulatory systems?

Answer 20

Open

Question 21

4 types of mollusks

Answer 21

1. Polyplacophora
2. Bivalvia
   3.Gastropoda
3. Cephalopod

Question 22

Hermaphrodite vs Dioecius

Answer 22

Hermaphrodite: Organisms can have both male and female organs
Dioecius: Organisms can only have female or male organs

Question 23

Do mollusks produce sexually or asexually?

Answer 23

BOTH