Zoology Test 2c Flashcards Preview

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Flashcards in Zoology Test 2c Deck (31)
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1
Q

annelids are….

A

segmented worms

2
Q

characteristics of annelids body form

A
  • eucolomates
  • possess a eucoelom or true body cavity
  • lined with peritoneum of mesodermal origin
  • peritoneum encloses internal organs
3
Q

advantages of true body cavity

A
  • allows for segmentation of body

- individual segments can move independently of each other, master burrowers

4
Q

peristalsis

A

contraction of muscles for movement of food

5
Q

mesentary

A

contains blood vessels, hold things in the right place

6
Q

what do nematodes and annelids have in common?

A
  • have bilateral symmetry and cephalization (only internal)
  • complete mouth to anus digestive tract
  • parasitism occurs in both groups, but annelids are mostly ectoparasites
  • no developed respiratory system
  • require wet or moist environment
7
Q

nematode muscles

A

muscular pharynx, but no muscles in intestine, contain longitudinal muscles

8
Q

annelid muscles

A

contain both circular and longitudinal muscles in body walls and digestive system

9
Q

nematode excretory system

A

use diffusion through excretory canals

10
Q

annelid excretory system

A
  • more complex
  • basic unit is the nephridium
  • nephridium covered in chlorogogue cells
11
Q

homoplasy

A

similarity probably due to convergent evolution

12
Q

homology

A

anatomy similar due to evolutionary derivation from common ancestor

13
Q

chlorogogue cells in annelids

A
  • cells that cover the peritoneum of the digestive system
  • convert waste product of protein metabolism to ammonia and urea
  • synthesize glycogen and fat from excess calories
14
Q

nematode circulatory system

A

contains no circulatory system

15
Q

annelid circulatory system

A

complex, closed circulatory system of arteries, capillaries and veins

  • have multiple hearts (aortic arches)
  • aortic arches regulate blood pressure
  • pumping done by muscular dorsal vessel
  • respiratory pigments present
16
Q

nematode respiratory system

A
  • no specialized structures to increase efficiency of gas exchange
  • done via diffusion
17
Q

annelid respiratory system

A
  • some contain “gills” or structures containing blood

- but most non- marine forms have no specialized structures and breath via diffusion

18
Q

nematode nervous system

A

dorsal and ventral nerve cords

19
Q

annelid nervous system

A
  • have ventral nerve cord connected to dorsally located brain via circumpharyngeal connectives
  • each segment has pair of nerves
20
Q

somite

A

means segment

21
Q

annelid classes

A
  • oligochaeta
  • polychaeta
  • hirudinea
22
Q

oligochaeta

A
  • mainly earthworms, have few setae

- Lumbricus terrestris

23
Q

setae

A

means bristles

24
Q

polychaeta

A
  • mainly marine annelids, many setae

- Nereis virens

25
Q

hirudinea

A
  • leeches
26
Q

characteristics of Lumbricus terrestris

A
  • type of oligochaeta
  • soil and freshwater annelid
  • with few and small setae
  • common earthworm
  • complete digestive system (mouth to pharynx to esophagus to crop to gizzard to gut)
  • monoecious, but don’t self fertilize
  • detrivores, important to recycling nutrients
27
Q

characteristics of Nereis virens

A
  • type of polychaeta
  • marine annelids
  • external cephalization
  • known as tube worms
  • contain parapodia
  • many setae
  • dioecious, no permanent organs
  • indirect development, contains a larvae stage
28
Q

parapodia

A

fleshy extensions of each somite

29
Q

characteristics of leeches

A
  • type of hirudinea
  • freshwater predator of invertebrates
  • ectoparasite of vertebrates
  • segmented but no setae
  • anterior and posterior suckers
  • monoecious with direct development
  • 4 to 12 pairs of testes and pair of ovaries
30
Q

how do leeches differ from annelids?

A
  • setae are lacking
  • no septa are present, but do have external segmentation
  • coelom is filled with connective or chlorogogue tissue
  • modified circulatory system, closed
  • digestive system is modified for fluid feeding
31
Q

septa

A

internal segmentation