2 - Fishes Flashcards
(29 cards)
In oceans no light beyond
1000 meters
Anglerfish adaptations
total darkness so:
- release mate attracting pheromones
- glowing bulb used of catching food
Desert pupfish
can withstand temps up to 45 degrees C
Crocodile icefish
- blood lacks red blood cells and haemoglobin
- clear blood
- contains anti-freeze chemical that prevents build up of ice crystals
When did this adaptive radiation begin
500mya
Ostracoderms
“fish” = oldest craniata
Teleostei
Most fish on planet now
Fish are ancestors of what
all other vertebrates
Subphylum craniata main characteristic
Skull that surrounds 3 part brain
Olfactory organs
Eyes
Inner ear
Subphylum craniata 2 infraphyla
- hyperotreti (hagfish)
2. vertebrata (vertebrates)
Infraphylum hyperotreti (hagfish) characteristics
Jawless Skull of cartilage Lack vertebrae and retain notochord No paired appendages Mouth with 4 pairs of tentacles Olfactory sacs open to mouth cavity 5-15 pairs of pharyngeal slits Ventrolated slime glands Tough, leather-like skin
Hagfish slime
Reacts with water to become slippery
Important for eating dead prey
More about hagfish
- Marine
- scavengers that feed off dead or dying organisms
- skin is used as leather
- 60 species
Superclass petromyzontomorphi class
class petromyzontida (lampreys)
Lamprey characteristics
- sucking mouth with teeth and rasping tongue
- 7 pairs of pharyngeal slits
- blind olfactory sacs
- true vertebrates but have ancient features
- 41 species
- marine and freshwater
- Some parasitic (ex: on lake trout) some not
- Complicated life style
- some are invasive species
Sea lamprey control programs
barriers, traps, lampricide
Ostracoderms are what
several classes of jawless fish
Ostracoderms characteristics
- 400 mya
- bony armour
- bottom dwellers
- probably filter feeders
- extinct
Superclass gnathostomata are what
jawed fishes
Gnathostoma 3 classes
chodrichthyes, actinopterygii, sarcopterygii
Importance of jaws
- led to predatory lifestyle in many fishes
- more efficient feeding so more offspring and exploitation of new habitats
- set stage for adaptive radiation of fishes
Class chondrichthyes 2 subclasses
elasmobranchii, holocephali
chondrichtyes characteristics
- tail fin with large upper lobe
- cartilaginous skeleton
- placoid scales ()
- lack opercula and a swim bladder or lungs
- Sharks, skates, rays, ratfishes
Placoid scales
skin feels like sandpaper, point posteriorly to reduce friction while swimming
