Intro to Diversity Flashcards
1
Q
Define “modern fish”
A
- aquatic vertebrate with:
—>gills
—>limbs (if present) in the form of fins
—> skin covered in scales
2
Q
What is the origin of scales?
A
DERMAL
3
Q
What type of group do fish form?
A
paraphyletic
4
Q
In an evolutionary sense, how can fish be defined?
A
- all vertebrates that are not tetrapods
5
Q
Approx. how many living species of fish are there?
A
- 34 000
6
Q
define paraphyletic group
A
- common ancestor but some groups are excluded
7
Q
Define monophyletic
A
- common ancestor and ALL of its descendants
8
Q
Approx how many species are discovered yearly?
A
- 200
9
Q
What is the defining feature of gnathostomata?
A
Jaws
10
Q
What is the defining feature of Chondrichthyes?
A
cartilaginous skeleton
11
Q
What is the defining feature of osteichthyes?
A
boned
12
Q
What is the defining feature of Agnetha?
A
jawless
