A History of Fishes Evolutionary History Fish have adapted to a - - PowerPoint PPT Presentation

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A History of Fishes Evolutionary History Fish have adapted to a - - PowerPoint PPT Presentation

Nov 11, 2022 275 likes •568 views

A History of Fishes Evolutionary History Fish have adapted to a wide range of environmental parameters Temperatures -1.8C - 40C pH 4 - 10 O 2 Concentrations 0 - Saturation Salinity 0 - 90 Depths 0 - 7000m A

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A History of Fishes

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A History of Fishes 2

Evolutionary History

  • Fish have adapted to a wide range of

environmental parameters

  • Temperatures
  • 1.8°C - 40°C
  • pH

4 - 10

  • O2 Concentrations

0 - Saturation

  • Salinity

0 - 90

  • Depths

0 - 7000m

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A History of Fishes 3

Diversity and Evolution

  • The diversity of fishes reflects their long

evolutionary history

  • A major challenge to ichthyologists involves

unraveling the evolutionary pathways of both extant (living) and extinct taxa

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Evolutionary History

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A History of Fishes 6

Conodonts

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A History of Fishes 7

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A History of Fishes 8

Ostracoderms

  • Characteristics:

1. Lack of jaws 2. Lack of paired fins 3. Bony armor 4. Internal cartilaginous skeleton

  • Modern day representatives of this group:
  • Class Pteraspidomorphi (hagfishes)
  • Class Cephalaspidomorphi (lampreys)
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A History of Fishes 9

Ostracoderms

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A History of Fishes 10

Early Jawed fishes

  • Gnathostomes
  • Jaws are probably the greatest advancement

in vertebrate evolution

  • This allowed for an explosion in diversity due to

the different prey items that can be processed

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A History of Fishes 11

Placoderms

  • Diverse group with a bizarre

appearance

  • 1. Jaws
  • 2. Dermal body plates
  • 3. Internal skeleton
  • 4. Paired fins
  • Some were over 6 meters in size and

possessed a craniovertebral joint

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A History of Fishes 12

Placoderms

Dinichthys Craniovertebral joint

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A History of Fishes 13

Placoderms

Gemuendina Bothriolepis

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A History of Fishes 14

Class Chondrichthyes

  • Arose during the early Paleozoic and followed a

very different line of evolution

  • Cartilaginous fishes
  • 2 distinct lines of evolution; the connection between

the two is poorly understood

  • Fossil record is poor, since cartilage does not readily fossilize
  • Characteristics
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A History of Fishes 15

Class Chondrichthyes

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A History of Fishes 16

Class Chondrichthyes

  • Two distinct evolutionary lines
  • 1. Subclass Elasmobranchii
  • Sharks, skates, and rays
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A History of Fishes 17

Class Chondrichthyes

  • Two distinct evolutionary lines
  • 2. Subclass Holocephali
  • Ratfishes or chimaeras
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Class Osteichthyes

Bony Fishes

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A History of Fishes 19

Subclass Sarcopterygii (Lobe-finned fishes)

  • Present day lungfishes and coelacanths
  • This group has paired fins which actually have muscle in the fin itself
  • It is this class which is believed to have given rise to the

amphibians

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A History of Fishes 20

Subclass Actinopterygii (Ray-finned fishes)

  • The most successful of all the modern fishes
  • 1. Triangular dorsal fin
  • 2. Paired fins without

fleshy lobes

  • 3. Ray-finned
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A History of Fishes 21

Subclass Actinopterygii (Ray-finned fishes)

  • Infraclass Chondrostei
  • Sturgeons, and paddlefishes
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A History of Fishes 22

Subclass Actinopterygii (Ray-finned fishes)

  • Infraclass

Neopterygii

  • Remaining

27,000+ bony fishes

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A History of Fishes 23

Subclass Sarcopterygii - lobe-finned fishes Present day lungfishes and coelcanth

Evolutionary Review

Ostracoderms - primitive jawless fishes

No living representatives, possible relatives include hagfish and lamprey

Class Placodermi - first jawed fishes No apparent descendants Class Chondrichthyes - cartilaginous fishes

Subclass Holocephali - ratfishes Subclass Elasmobranchii - sharks, skates, & rays

Class Osteichthyes - bony fishes Subclass Actinopterygii - ray-finned fishes

Infraclass Chondrostei - sturgeons & paddlefishes Infraclass Neopterygii - remaining bony fishes

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A History of Fishes 24

Population Distributions

  • By volume, 97% of all water on earth is

found in the worlds oceans

  • 58% of all fish species are marine
  • 41% are freshwater species
  • 1% move between the two habitats
  • Marine Habitat
  • 13% of marine species associate in open water
  • 78% live over the continental shelf
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A History of Fishes 25

Physical Properties of Water

  • Water is 800x denser than air!
  • Water is incompressible
  • Water is a universal solvent
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A History of Fishes 26

Nomenclature

  • The most frustrating

aspect of ichthyology is the constant changing

  • f scientific names
  • These names change

for several reasons

  • Changes are necessary

as new information is discovered concerning evolutionary history

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A History of Fishes 27

Species Names

  • Each spp. is assigned a unique two part

scientific name

  • Longnose Dace Rhinichthys cataractae

(Valenciennes 1842)

  • Names are usually descriptive in some way
  • Rhinichthys - nose-fish
  • cataractae - the fast water in which it lives
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A History of Fishes 28