Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

VBSC 421: Comparative Vertebrate Anatomy > Lecture 6: Origin of Chordates > Flashcards

Lecture 6: Origin of Chordates Flashcards

1
Q

Pelagic

A

Relating to deep ocean, Planktonic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Benthic

A

Relating to the bottom of a body of water, Sessile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Paedomorphosis

A

Retention of juvenile features in descendant adults. This is a key discovery in explaining the development of chordates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Synapomorphy

A

An evolutionarily derived character-state that indicates sharing taxa are each other’s closest relatives

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which are the 3 most prevalent species?

A
  1. Arthropoda
  2. Nematodes
  3. Mollusca
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What kind of evidence can we use to help us find where chordates originated from?

A
  1. Paleontologic evidence - based on fossil evidence

2. Neontologic evidence - based on living animals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Complications with Paleontologic evidence

A
  1. Many early species did not leave behind fossils
  2. No retention of soft tissue
  3. Lack of embryonic development
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Complications with neontologic evidence

A
  1. Current living animals also underwent continual evolution
  2. May not reflect what was in the past
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What was the original theory regarding the origins of chordates?

A

Originally, it was theorized that chordates originated from arthropods. This theory was based on a comparison of analogous structures rather than homologous ones. The ventral nerve in arthopods vs dorsal nerve in chordates.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Auricularian hypothesis

A

Another chordate origin theory. It hypothesized that chordates originated from echinoderms through the retention of juvenile features during embryologic stages. These eventually would lead to the known chordate characteristics.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the CURRENT theory regarding the origins of chordates?

A

Radial evolution of deuterostomes (prechordate).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Do protostomes and deuterostomes have bilateral or radial symmetry?

A

Both have bilateral symmetry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are characteristics of protostomes?

A
  1. Means “first mouth”
  2. Blastopore forms mouth
  3. Spiral cleavage
  4. Coelom develops from mesoderm separation
  5. Ectodermal skeleton
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which groups are protostomes?

A

Molluscs, annelids, and arthropods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are characteristics of deuterostomes?

A
  1. Means “second mouth”
  2. Blastopore forms anus
  3. Radial cleavage
  4. Coelom develops as outpouching of primitive gut
  5. Mesodermal skeleton
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which groups are deuterostomes?

A

Echinoderms, hemichordates, chordates

17
Q

Do protostomes and deuterostomes share the same evolutionary line?

A

No, they come from two distinct and independent evolutionary lines

18
Q

What are the 5 chordate characteristics?

A
  1. Notochord
  2. Dorsal Nerve Chord
  3. Pharyngeal slits
  4. Endostyle (or thyroid gland)
  5. Post-anal tail
19
Q

Notochord

A

An elastic, fluid filled structure that provides support for the body and facilitates animal movement (swimming) by accentuates muscle actions.

20
Q

Pharyngeal slits

A

The digestive tract chamber just posterior to the mouth. In early chordates, these facilitated feeding mechanisms. They are present in all chordates now, but are not always functional.
Not gills –> but modifications will support gills in future vertebrates.

21
Q

Protochordates

A
  1. All marine animals
  2. Feed by cilia and mucus (filtration)
  3. Larval forms generally pelagic or planktonic
  4. Adult forms generally benthic or sessile
22
Q

What are the 3 protochordate groups?

A
  1. Hemichordata - “acorn worms”
  2. Urochordata - “sea squirts”
  3. Cephalocordata - Amphioxus
23
Q

How are hemichordates similar to chordates?

A
  1. Deuterostomes
  2. Pharyngeal slits
  3. Invagination of nerve chord
  4. Lack notochord (stomochord not equivalent) , tail
24
Q

What are hemichordates’ phylogenetic affinities?

A
  1. Links to chordates and echinoderms

2. Connection between chordate ancestry and invertebrates

25
Q

Enteropneusts

A

AKA Acorn Worms, they are hemichordates that burrow into the sea floor

26
Q

What are the 3 regions of enteropneusts?

A
  1. Proboscis
  2. Collar
  3. Trunk
27
Q

Pterobranchia

A

A hemichordate that are colonial organisms and that live in secreted tubules

28
Q

Cephalochordates chordate components

A
  1. Pharyngeal slights
  2. Notochord
  3. Tubular nerve chord
  4. Post-anal tail
29
Q

Lancelets (amphioxus)

A

Cephalochordates that occur worldwide in warm temperatures and tropical seas. They use suspension feeding via a pharyngeal feeding apparatus.
Larval form planktonic.

30
Q

Urochordates

A

Name means “tail backstring). They show all 5 chordate characteristics at one point during their life cycle

31
Q

What are the 3 classes of urochordates?

A
  1. Ascidiacea(Sea Squirts) –sessile adults, planktonic larvae
  2. Larvacea– pelagic adults/larvae
  3. Thaliacea– pelagic adults/larvae

VBSC 421: Comparative Vertebrate Anatomy (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions