Evolution of Fish

1
Evolution of Fish
2
(No Transcript)
3
Lets start 390 million years ago

• During the Devonian Period, there were many
  creatures living in the oceans (some on their way
  to becoming the true bony fish of today!)

4
Placoderms

• Name means plated skin
• First seen 390 million years ago
• Extinct 345 million years ago
• Had true jaws
• Many were small bottom dwellers, but many more
  were bottom dwelling predators
• Armor plates on their skin

5
A Placoderm
6
Next came the Chondrichthyes
Kingdom Animalia
Phylum Chordata
Subphylum Vertebrata

Class Chondrichthyes
7
Chondrichthyes

• First seen 375 million years ago
• Theyre still around today
• Includes sharks and skates
• Sharks are sometimes called living fossils
• Developed cartilaginous skeletons

8
Chondrichthyes of old.
9
(No Transcript)
10
Osteichthyes

• Modern bony fish
• First appeared 395 million years ago
• Ray-finned fish of today are still the dominant
  fish group
• True bones

11
Osteichthyes
12
Osteichthyes branched into Actinopterygii

• KingdomAnimalia
• PhylumChordata
• SuperclassOsteichthyes
• Class Actinopterygii
• Ray-finned bony fish
• Fins are webs of skin supported by bony or horny
  spines.
• They are the dominant aquatic vertebrates today,
  making up about half of all vertebrate species
  known

13
and Sarcopterygii
Kingdom Animalia
Phylum Chordata
Superclass Osteichthyes
Class Sarcopterygii
14
Sarcopterygii

• Name means fleshy finned fishes
• First appeared 385 million years ago
• Ancestors of land vertebrates!
• Internal nostrils, fleshy fins and cosmoid scales

15

• 1. What does this mean that sharks are living
  fossils?

16
Sea to Land Transition
17
Sea to Land Transition

• Scientists think that the major cause for marine
  life moving on to land was a lack of oxygen in
  the water.
• There was also fierce competition for food in the
  oceans.
• Also, at this time insects were becoming very
  plentiful on land.
• 2. What do you think would be required for this
  sea to land transition to occur?

18
(No Transcript)
19
Tiktaalik roseae
20
Tiktaalik roseae
21
Tiktaalik roseae

• First seen 375 million years ago
• Large aquatic predator with a flattened head and
  body
• Scientists think that Tiktaalik lived on the
  bottom of the ocean in shallow water
• Tiktaalik might have been able to come out of the
  water for brief periods of time
• Skull, neck, ribs and limbs are similar to the
  earliest limbed animals
• Had fish-like features such as scales and fin rays

22
Tiktaalik roseae

• Discovered on Ellesmere Island, Canada in 2004
• Name means large freshwater fish in Inuktituk

23
Tiktaalik roseae