Chapter 18 Fish

8/2/2019 Chapter 18 Fish

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Chapter 18The Fishes: Vertebrate

Success in Water

Zoology


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Fish: A Long History

The earliest fossils are

from 500 million yearsago.

Highly evolved/adaptedfor living in water

environments.


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Water and Fish

Water covers about 75% of the Earths surface.

By volume, only .009% is freshwater However, 41% of fish species are freshwater

+
http://images.google.com/imgres?imgurl=http://whatscookingamerica.net/Information/Salt1.jpg&imgrefurl=http://whatscookingamerica.net/Information/Salt.htm&usg=__8ZxuBClnhiHSdDD8ovuUhT6bvUk=&h=373&w=432&sz=30&hl=en&start=1&um=1&tbnid=k4KyB5_VkeMusM:&tbnh=109&tbnw=126&prev=/images%3Fq%3Dsalt%26hl%3Den%26um%3D1http://images.google.com/imgres?imgurl=http://weblogs.newsday.com/news/local/longisland/politics/blog/water.jpg&imgrefurl=http://www.arktimes.com/blogs/shale/&usg=__1vQePJn4Vqa-vKeyVzyjyLk0TxY=&h=640&w=800&sz=89&hl=en&start=3&um=1&tbnid=L73Dwc8okR-zSM:&tbnh=114&tbnw=143&prev=/images%3Fq%3Dwater%26hl%3Den%26um%3D1http://images.google.com/imgres?imgurl=http://www.fpaa.com.au/images/water.jpg&imgrefurl=http://www.fpaa.com.au/news/&usg=__WSKjVIEHe6B9dDvekqHy7hojT6k=&h=426&w=640&sz=35&hl=en&start=6&um=1&tbnid=Gd2twEEWqHZcfM:&tbnh=91&tbnw=137&prev=/images%3Fq%3Dwater%26hl%3Den%26um%3D1


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Water Presents Unique Challenges

How to move around

How to get air

How to float

How to sense what is around me


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Movement

Fish Shape- Fish are streamlined to minimize

resistance. Fish Skin- It is slimy, covered with mucous

secretions to reduce friction

Fish Paddles- The fins of fish allow for

movement.


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Gas Exchange

Water has 2.5% the free oxygen as air.

Gills- Need to be very efficient at gas exchange. They are composed of lots of tiny folds called

lamellae.

Capillary beds move in opposite direction to water

flow allowing forcountercurrent exchange ofoxygen.


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Diagram of Gas Exchange


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Gas Exchange (Cont.)

Water needs to be constantly moved over thegills.

Ram Ventilation- Adaptation of swimming withmouth open.

Operculum- A gill covering that can pump in water.
http://images.google.com/imgres?imgurl=http://susty.com/image/hammerhead-shark-underwater-blue-ocean-dorsal-fins-mouth-swimming-sunlight-swim-deep-sea-sharkwater-documentary-filmmaker-rob-stewart-photo.jpg&imgrefurl=http://susty.com/sharks-species-spotlight/&usg=__R3rKAbTtkCS7315MVaHqTI2YcjY=&h=270&w=468&sz=9&hl=en&start=12&tbnid=em2_AirdT6ChEM:&tbnh=74&tbnw=128&prev=/images%3Fq%3Dfish%2Bswim%2Bwith%2Bmouth%2Bopen%26gbv%3D2%26hl%3Den


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How to float

Floating/Sinking is dependenton density.

Float=Less dense than water

Sink=More dense than water

4 Methods for floating

Low density oils Low density bones

Fins

Pneumatic sacs- lungs or swimbladder that can be filled withair.
http://images.google.com/imgres?imgurl=http://img6.travelblog.org/Photos/17776/256478/f/2094680-Floating-in-the-Dead-Sea-1.jpg&imgrefurl=http://www.travelblog.org/Photos/2094680.html&usg=__USfg6JA0g_bf5r78WVBjYeRz08E=&h=600&w=600&sz=34&hl=en&start=4&tbnid=LEl1OM4-6hJ8XM:&tbnh=135&tbnw=135&prev=/images%3Fq%3Dfloating%26gbv%3D2%26hl%3Denhttp://images.google.com/imgres?imgurl=http://gallery.hd.org/_exhibits/places-and-sights/_more2002/_more01/Cuba-Trinidad-Caribbean-Sea-Playa-Ancon-woman-floating-on-clear-water-shadow-1-MY.jpg&imgrefurl=http://mirror-us-ga1.gallery.hd.org/_c/places-and-sights/_more2002/_more01/Cuba-Trinidad-Caribbean-Sea-Playa-Ancon-woman-floating-on-clear-water-shadow-1-MY.jpg.html&usg=__L6xWseJVUfsdndTCBGIifEn33CM=&h=1232&w=1840&sz=849&hl=en&start=2&tbnid=cIOaiZH51tGsIM:&tbnh=100&tbnw=150&prev=/images%3Fq%3Dfloating%26gbv%3D2%26hl%3Den


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Sensory Functions

Fish have eyes, nose, and ears

Additionally Lateral line system- collection of sensory nerves that

run in a line along the sides of fish.

Can sense currents or predator/prey movements.

Electroreception-Detection of electrical fields fromnerves and muscles of the other organisms.
http://images.google.com/imgres?imgurl=http://static.howstuffworks.com/gif/electroreception-1a.jpg&imgrefurl=http://animals.howstuffworks.com/fish/electroreception.htm/printable&usg=__z-WPL7zO4GaDOSJ_99oEGBhmhZ0=&h=267&w=400&sz=8&hl=en&start=2&tbnid=KSgoGGXXNiRTwM:&tbnh=83&tbnw=124&prev=/images%3Fq%3Delectroreception%26gbv%3D2%26hl%3Den


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Fish Adaptations

Where did all the fishadaptations come from?

Evolution caused by naturalselection.

Evolution can lead to theformation of new species, calledspeciation.

Natural selection- Idea that anorganisms environment causesthe best adapted to survival andthus pass on their traits.

Survival of the fittest


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Diversity of Fish

The diversity of fish is

thought to have arosefrom adaptiveradiation.

Adaptive radiation-

When an originalancestor diverges intomany different species.


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Subphylum Hyperotreti

Hagfish Most primitive fish

No true vertebrate

Slimy Secretions

Live as scavengersof dying fish
http://images.google.com/imgres?imgurl=http://bakkouz.net/pix/Hagfish.jpg&imgrefurl=http://bakkouz.net/%3Fp%3D101%26cp%3Dall&usg=__P5tGWWMDxHixIPpr4mjiqoRVObw=&h=359&w=384&sz=18&hl=en&start=7&tbnid=afUAWxnHAWdwDM:&tbnh=115&tbnw=123&prev=/images%3Fq%3Dhagfish%26gbv%3D2%26hl%3Denhttp://images.google.com/imgres?imgurl=http://oceanexplorer.noaa.gov/explorations/lewis_clark01/logs/jul08/media/r609hagfish_532.jpg&imgrefurl=http://oceanexplorer.noaa.gov/explorations/lewis_clark01/logs/jul08/media/hagfish.html&usg=__D-fWsT9HPVGrNjGGvrAZNSWeQRI=&h=480&w=562&sz=26&hl=en&start=1&tbnid=-I3rEWesYX4UTM:&tbnh=114&tbnw=133&prev=/images%3Fq%3Dhagfish%26gbv%3D2%26hl%3Den


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Class Agnatha

(a- = not, without;

gnatho = jaw) The lampreys.

Dont have jaws,often parasitic

The most primitiveform of fish with atrue vertebrate

Lamprey
http://images.google.com/imgres?imgurl=http://wupcenter.mtu.edu/education/Ecology_of_the_Great_Lakes_03/13lamprey_hickey.jpg&imgrefurl=http://wupcenter.mtu.edu/education/Ecology_of_the_Great_Lakes_03/13lamprey_hickey.html&usg=__fmYasazKajU8PE9gS_vc3EbsS4I=&h=480&w=640&sz=81&hl=en&start=3&tbnid=hJNZeuIN3EPipM:&tbnh=103&tbnw=137&prev=/images%3Fq%3Dlamprey%26gbv%3D2%26hl%3Den


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Two Classes of Jawed Fish

Class Osteichthyes Bony Fish

Class Chondrichthyes Cartilage Fish

Two different responses to selectionpressures.

Each have advantages and disadvantages.


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Class Chondrichthyes Cartilage Fish

(chondro = cartilage; ichthys = fish)

Sharks and rays They have a cartilage

skeleton, not bone.

Their backbone extends into their caudal fin


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Class Chondrichthyes Cont.

Advanced Electroreception

They also fertilize internally. Produce fewer eggs, less

young tend to die.

Lack operculum, lungs, andswim bladder


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Class Osteichthyes Bony Fish

(osteo = bone)

Bony fish. 24,000 Species

Operculum

Swim bladder or lungs 90% of members

fertilize externally.

Lots of eggs
http://thundafunda.com/33/underwater-animals-fish/School%20of%20Tropical%20Fish,%20Tahiti%20pictures%20underwater%20photos.jpg


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THE END!

Chapter 18 Fish

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