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Flashcards in Annelida Deck (46):
1

What does the Phylum Annelida contain

Segmented worms living in marine, freshwater, and moist terrestrial habitats

2

How many species are there in Phylum Annelida

15, 000

3

The body divided into a serial succession of repeated units

Segmentation/Metamerism

4

What are the five significances of Segmentation/Metamerism?

-independently evolved -greater complexity in structure and function
-Burrowing efficiency
-Fine control –nervous system
-Redundancy –safety

5

external circular grooves delimiting body segments

Annuli

6

What is Septa (partition)

internal delimitation of body segments

7

Function of the Head

Sensory and feeding

8

What are the two parts of the head and where are they found

Prostomium: anterior most region of the body, anterior to the mouth

Peristomium: pre-segmental region of the body surrounding the mouth.

9

What does the nervous system in Annelida contain?

double ventral nerve cord and a pair of ganglia with lateral nerves in each segment;
brain a pair of dorsal cerebral ganglion with connections to ventral nerve cord

10

What system has tactile organs, taste buds, statocysts (in some), photoreceptor cells, and eyes with lenses (in some)

Sensory

11

What is coelom filled with fluid (except for leeches)

The Hydrostatic skeleton

12

The Hydrostatic skeleton does what?

-Fluid volume constant
-Contraction of longitudinal muscles shorten and expand the body
-Contraction of circular muscles narrow and lengthen the body
-Alternate waves of contraction, or peristalsis, allow efficient burrowing
-Swimming annelids use undulatory movements

13

Do Oligochaetes & Polychaetes have an open or closed circulatory system

closed

14

dorsal vessels carry blood

Anteriorly

15

ventral vessels carry blood

Posteriorly

16

What has:
dorsal vessel is contractile
Aortic arches maintain steady pressure in ventral vessel

The heart

17

excretory organs of the adult annelid

Metanephridia

18

Which section of excretion is highly vascularized with a capillary network

Metanephridia

19

- ciliated funnel that draws in coelomic fluid
- opens into segment anterior
to metanephridium

nephrostome

20

nephridiopore functions

terminal end of metanephridium
- opens to the outside,
eliminated waste
- in some forms, nephridiopores are enteronephric

21

tolerate a wide range of salinity,

Euryhaline

22

What class is:
Largest class of annelids - 10,000 species,
mostly marine and usually benthic
some live in crevices, others inhabit tubes, or are pelagic

Class Polychaeta

23

What was only discovered in 1977. 2 km depth.
Tube worms
Extremophile environment

Deep sea hydrothermal vents

24

Prostomium

retractile or not
Often bears eyes, tentacles, and sensory palps

25

Peristomium

surrounds mouth and may have setae, palps, or chitinous jaws

26

Ciliary feeders may bear a ____ that opens like a fan but can be withdrawn into the tube

tentacular crown

27

2 morphotypes of Polychaeta, what are they

Sedentary-mainly tube-living

Errant- may be free-moving, burrowing, or crawling

28

What clade has Earthworms & Leeches
Freshwaters, or terrestrial soils

Clade Clitellata

29

Form reproductive structure called a

clitellum

30

What clade has NO parapodia
Hermaphroditic (monoecious) - with direct development

Clade Clitellata

31

Class Oligochaete occur where?

Over 3000 species
Occur in habitats from soil to freshwater
Few are marine or parasitic
Nearly all bear setae
Fewer in number than in polychaetes

32

Earthworms - sometimes called

“night crawlers”

33

with pores for mucus secretion

Cuticle

34

epithelial cells + mucous, sensory and photoreceptor cells

Epidermis

35

circular muscles

metamere elongation

36

paired chitinous “bristles” to increase traction typically ventro- and dorsolateral

setae

37

Oligochaeta Locomotion
Mechanism:

waves of peristaltic contraction

38

waves of peristaltic contraction is when

Contractions of circular muscles in the anterior end lengthen the body, pushing the anterior end forward where it anchors
Anchoring is accomplished by contraction of the longitudinal muscles in forward segments

39

What class is Most freshwater, few marine or live in moist terrestrial environments
More common in the tropics
Vary in color: black, brown, red, and olive green
Most are flattened (dorsoventrally)

Class Hirudinida: Leeches

40

What type of feeding do Hirudinida have

most carnivores feeding on small invertebrates
others - temporary or permanent parasites

41

What usually has a fixed number of segments and why?

Leeches because they Appear to have more due to superficial annuli

42

What do Leeches not have

NO distinct coelomic compartments
NO septa
Developed suckers for attachment

43

Most leeches are

-predaceous, some parasites,
-Most are fluid feeders that prefer tissue fluids and blood pumped from open wounds

44

have chitinous ‘jaws” and salivary glands

Bloodsucker leeches

45

Leech Locomotion is by

musculature & suckers, looping

46

both suckers attached
anterior sucker detachment
contraction of circular muscles
body lengthens
anterior sucker attachment
circular muscles relax
longitudinal muscles contract
Posterior sucker is detached
dorsal longitudinal relax
ventral longitudinal muscles contract
- posterior sucker attaches

Leech locomotion