Lecture 13 Flashcards Preview

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Flashcards in Lecture 13 Deck (24)
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1
Q

Symbiosis in Cnidarians examples

A

• Obligate Mutualism
Anemonefish can’t survive without
protection of an anemone
• Facultative Mutualism
Sea anemones can survive without an anemonefish

2
Q

Symbiosis with Zooxanthellae algae

A

Coral gets energy from the zooxanthellae’s ‘photosynthetic leftovers

3
Q

Worm Phyla

A
  • Phylum Platyhelminthes
  • Phylum Nematoda
  • Phylum Annelida
4
Q

Worm Body Plans

A

platyhelminthes- Acoelomate
Nematodes- Pseudocoelomate
Annelids- Coelomate

5
Q

Phylum Platyhelminthes characteristics

A
Commonly called ‘flatworms’
Most are parasitic
Triploblastic
Acoelomate
 Bilateral symmetry
Cephalization
Hydrostatic skeleton
Incomplete(‘blind’)gut
 Reproduction: Asexual and Sexual (usually monoecious)
“Tissue-Organ”level of biological complexity (no systems)
6
Q

How do platyhelminthes breathe

A

via diffusion

7
Q

Phylum Platyhelminthes Classes

A
• Class Turbellaria
      Mostly free living (not parasitic)
        e.g. planaria
• Class Cestoda
       Parasitic
      ex Tapeworms
• Class Trematoda 
         Parasitic
         Flukes
8
Q

Class Turbellaria Characteristics

A
  • Only class of flatworms that has free-living members
  • Some symbiotic
  • Blind gut – waste ejected through mouth
  • Sexual and Asexual Reproduction
9
Q

Class Cestoda: tapeworms body composition

A

Long flat body composed of…
• Scolex, for attachment to the host
• Strobila, main body composed of chain of proglottids
• Proglottids, reproductive units

10
Q

Class Cestoda characteristics

A

Class Cestoda= Tapeworms
• Nearly all monoecious
Proglottids fertilized by another proglottid on
the same or a different strobila
• Shelled embryos form in the uterus of the proglottid
• Strobilation
New proglottids form behind scolex
• Terminal gravid proglottids break off and are excreted in host’s feces

11
Q

Class Trematoda characterisitcs

A

Class Trematoda=parasitic flukes
Almost all endoparasites of vertebrates
leaflife body form

12
Q

Which class and species are in the phylum Platyhelminthes

A

Class Turbellaria species Flatworms
Class Cestoda species tapeworms
Class Trematoda species flukes

13
Q

What class and species are in phylum Nematoda

A

No class, species roundworms

14
Q

What class and species are in phylum Annelida

A

Polychaeta ,marine worms

Oligochaeta, earthworms

Hirudinida, leeches

15
Q

Phylum Nematoda Characteristics(11)

A

Phylum Nematoda= roundworm
• Triploblastic
• Pseudocoelomate
• Bilateral Symmetry
• Cephalization
• Hydrostatic skeleton formed by fluid filled pseudocoelom
• Ecdysozoans
• Have a molted cuticle (non-living external layer secreted by the epidermis)
• Complete gut
• Reproduction: sexual, most dioecious
• Organ-system level of biological complexity
• Have a full digestive system, but lack a circulatory system

16
Q

Differences between Nematoda and Platyhelminthes

A
Nematoda have:
       Pseudocoelomate
      Hydrostatic skeleton formed by fluid filled pseudocoelom 
       Ecdysozoans
        Have a molted cuticle

have a Complete gut
have organ systems (ie digestive system, no circulatory)

Platyhelminthes

  • Acoelomate
  • Cephalization
  • Incomplete(‘blind’)gut
  • Organ tissue
17
Q

Phylum Annelida characterisitcs

A

Phylum Annelida= earthworms, leeches,freshwater worms
• Triploblastic
• Coelomate
• Bilateral Symmetry, Cephalization, Hydrostaticskeleton
• Lophotrocozaoan
• Has trochophore larvae
• Complete gut
• Reproduction:Asexual and Sexual (monoecious or dioecious)
• Organ-system level of biological complexity
• Exhibit Metamerism
• Many have setae

18
Q

What is Metamerism

A

Worms have em
• Being composed of serially repeating parts;serial segmentation
• Segments are called metameres or somites
•Segments can be repetitive, but not identical
•Evolved differently in each group

19
Q

Benefits of Metamerism

A

Allows for greater complexity in structure and function possible

20
Q

Pseudometamerism

A

In tapeworms
Repeated segments are independent of each other
Each contains a complete set of organs

21
Q

Reproduction for Oligochaeta

A

Oligochaeta= earthworm
• Monoecious
• do not self-fertilize
• Mate on the surface (at night)

22
Q

Earthworm Reproduction -description

A

• Extend anterior ends from burrows, press ventral surfaces together
• Held together by mucus
Ventral setae also penetrate eachother’s bodies
• Sperm discharged and travels along the seminal groove (externally)
into the seminal receptacle of the other worm
• Worms separate
• Each worm secretes around its clitellum…
first,a mucous tube
then,a tough band that forms a cocoon
• Cocoon slides forward along body
• As it moves the following are mixed in the cocoon:
Eggs from oviducts(from genital pore)
Albumin(from skin glands)
Sperm from mate(stored in seminal receptacles)
• Fertilization of eggs occurs in the cocoon
• Cocoon slides off the head end of the worm
• Embryonic development occurs within the cocoon

23
Q

how to Polychaeta differ from other annelids

A
  • Well-differentiated head
  • Specialized sense organs
  • Paired paddlelike appendages (parapodia)
  • Many chaetae on each parapodium
  • No clitellum
24
Q

Class Hirudinida characteristics

A
Leeches
• Fixed number of segments (usually 34)
• No parapodia or setae
• Variable dietary strategies:
• carnivores on small invertebrates
• temporary parasites: sucking blood from vertebrates
• permanent parasites: don’t leave host
• Monoecious, cross-fertilization
• Clitellum is evident only during the breeding season