FISHES Chapter 30. Learning Targets 30.2 Identify the characteristics of fishes Summarize the...
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Transcript of FISHES Chapter 30. Learning Targets 30.2 Identify the characteristics of fishes Summarize the...
FISHESFISHESChapter 30Chapter 30
Learning Targets 30.2Learning Targets 30.2
Identify the characteristics of fishes
Summarize the evolution of fishes.
Explain how fishes are adapted for life in water.
Describe the three main groups of fishes
Identify the characteristics of fishes
Summarize the evolution of fishes.
Explain how fishes are adapted for life in water.
Describe the three main groups of fishes
Fishes
Fishes are aquatic vertebrates that are characterized by
Paired finsScalesGills
Fishes are so varied, however, that for almost every general characteristic there are exceptions.
Example: Catfish don’t have scales
Evolution of Fishes
They did not arise directly from tunicates or lancelets.
Fishes and non-vertebrate chordates evolved from common invertebrate ancestors.
The evolution of jaws and the evolution of paired fins were important developments during the rise of fishes
Evolution of Fishes The first fishes were thought to be
jawless creatures whose bodies were armored with bony plates
The Arrival of Jaws and Paired FinsJaws make it possible for vertebrate to nibble
on plants and to munch on other animalsAnimals with jaws are able to eat a wide
variety of foodThey are able to defend themselves by bitingThese adaptations alone have increased
survival
Form and Function in Fishes
Adaptations to aquatic life include:Various modes of feedingSpecialized structures for gas exchangePaired fins for locomotion
Feeding and Respiration in Fishes
Feeding:Every mode of feeding is displayed
Respiration:Most fishes exchange gases using gills
that are located on either side of the pharynx
Circulation in Fishes
Fishes have a closed circulatory system
The system has:HeartIt pumps blood around the body in a single loop
Single Loop Circulatory SystemSingle loop from the heart to the gillsFrom the gills to the rest of the bodyThen back to the heart
Excretion
Like many other aquatic animals, most fishes get rid of nitrogenous waste in the form of ammonia.
Some of the waste will diffuse through the gills into the surrounding water
Others will remove waste by kidneysThese are excretory organs that filter wastes
from the blood.
Excretion cont.
Kidneys help to control the amount of water that is in their bodies
Fishes in saltwater tend to lose water by osmosis and excrete concentrated wastes
In contrast, freshwater fishes pump out plenty of dilute urine.
Response
Fishes have well developed nervous systems organized around a brain with many parts
The cerebrum is responsible for all voluntary activities in the body
The cerebrum of fish primarily processes the sense of smell
Fish Brain
Fish Brain
Response The optic lobe processes information
from the eyesThe cerebellum coordinates body
movementsThe medulla oblongata controls the
functioning of many internal organsIn addition, fishes use a lateral line
system to sense motion of other fishes or prey
Fish Brain
Fish Brain
Movement
Fishes move by alternately contradicting paired sets of muscles on either side of their backbone.
Many bony fishes have an internal, gas filled organ called a swim bladder
It adjusts the fishes buoyancy
Reproduction
The eggs of fishes are fertilized either internally or externally
Types of Development:OviparousOvoviviparousViviparous
Reproduction Oviparous:
Eggs hatch outside the mother’s bodyExample: Salmon, fish, and crocodiles
Ovoviviparous:Eggs stay in the mother’s body and the young are then
born aliveObtain the nutrients needed from the egg yolkExample: Insects, fish, snakes, and lizards
Viviparous:The young are born aliveThe young obtain nutrients directly from the mother’s bodyExample: Humans, snakes
Groups of Fishes
Groups of Fishes
Groups of Fishes
When you consider their basic internal structure, all living fishes can be classified into three groups:
Jawless FishesCartilaginous FishesBony Fishes
Jawless Fishes
Have no teeth or jawsSkeleton are made of fibers and
cartilageThey lack vertebrae and keep their
notochords as adultsModern jawless fishes are divided into
two groups:LampreysHagfishes
LampreyLamprey
HagfishHagfish
Sharks and their Relatives
The class: ChondrichthyesContain:
Sharks, Rays, Skates, Sawfishes and Chimaeras
The skeletons of these fishes are built entirely of cartilage….NOT bone
Bony Fishes
The class: OsteichthyesContain: Combtooth Blenny, Emperor
Angelfish, Flying Fish, Peacock Flounder, Leafy Sea Dragon
Examples: Almost all living bony fishes belong to a huge group called ray-finned fishes
The skeletons of these fishes are made of hard, calcified tissue called bone
The End!The End!
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Elements Page