two layers of cells that form tissues - cells that act as a functional unit gastrovascular cavity...
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Two layers of cells that form TISSUES - cells that act as a functional unit
Gastrovascular cavity that allows for extracellular digestion - large food particles broken down so that the gastrodermis can do intracellular digestion.
Simple nerve net forms nervous system - no brain
Two layers of cells that form TISSUES - cells that act as a functional unit
Gastrovascular cavity that allows for extracellular digestion - large food particles broken down so that the gastrodermis can do intracellular digestion.
Simple nerve net forms nervous system - no brain
Phylum Cnidaria: Cnidarians have radial symmetry, a gastrovascular cavity, and cnidocytes
• There are about 20,000 species of flatworms living in marine, freshwater, and damp terrestrial habitats.– They also include many parasitic species, such as the
flukes and tapeworms.
• Flatworms and other bilaterians are triploblastic, with a middle embryonic tissue layer, mesoderm, which contributes to more complex organs and organs systems and to true muscle tissue.
1. Phylum Platyhelminthes: Flatworms are acoelomates with gastrovascular cavities
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Two way gut
ventral nerve cords
Cephalization - brain, eye spot at head
gastrovascular cavity
acoelomate
Two way gut
ventral nerve cords
Cephalization - brain, eye spot at head
gastrovascular cavity
acoelomate
• The phylum Mollusca includes 150,000 known species of diverse forms, including snails and slugs, oysters and clams, and octopuses and squids.
• Most mollusks are marine, though some inhabit fresh water, and some snails and slugs live on land.
• Mollusks are soft-bodied animals, but most are protected by a hard shell of calcium carbonate.– Slugs, squids, and octopuses have reduced or lost their shells
completely during their evolution.
5. Phylum Mollusca: Mollusks have a muscular foot, a visceral mass,
and a mantle
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Radula is used for rasping food off of surfaces, but can be modified to bore holes or tear apart tough animal tissue
Radula is used for rasping food off of surfaces, but can be modified to bore holes or tear apart tough animal tissue
Has trochophore larvae a type of ciliated larvae
Has trochophore larvae a type of ciliated larvae
They lack true segmentation
They lack true segmentation
Mantle secretes the shell
Mantle secretes the shell
Gastropoda is the largest molluscan class
During embryonic development it undergoes torsion which results in its asymmetrical shape
Gastropoda is the largest molluscan class
During embryonic development it undergoes torsion which results in its asymmetrical shape
bivalves
Annelids have a true coelom - which allows for easier fluid movement between organs
They have body segmentation - each segment can become specialized
closed circulatory system with hearts- blood with hemoglobin
excretory tubes called metanephridia collects wastes from the blood through a funnel called a nephrostome and dumps it outside through nephridia pores.
Annelids have a true coelom - which allows for easier fluid movement between organs
They have body segmentation - each segment can become specialized
closed circulatory system with hearts- blood with hemoglobin
excretory tubes called metanephridia collects wastes from the blood through a funnel called a nephrostome and dumps it outside through nephridia pores.
complete digestive tractcomplete digestive tract
Phylum Nematoda: Roundworms are nonsegmented pseudocoelomates covered by tough cuticles
BLASTULABLASTULA
invaginationinvagination
GASTRULAGASTRULA
NEURULANEURULA
Forms mouth in protostomes
Forms mouth in protostomes
Arthropods are segmented coelomates with exoskeletons and jointed appendages
The diversity and success of arthropods is largely due to three features: body segmentation, a hard exoskeleton, and jointed appendages.
Crustaceans
Spiders have
cheicerae - piercing mouth parts
a pair of appendages called pedipalps used for sensing or feeding
four pairs of walking legs
book lungs used for gas exchange
Spiders have
cheicerae - piercing mouth parts
a pair of appendages called pedipalps used for sensing or feeding
four pairs of walking legs
book lungs used for gas exchange
Insecta is the largest class
3 body parts with 3 pairs of legs
two pair of wings
nitrogenous waste excreted through Malpighian tubules
gas exchange through tracheal tubes
mandibles (jaws)
Insecta is the largest class
3 body parts with 3 pairs of legs
two pair of wings
nitrogenous waste excreted through Malpighian tubules
gas exchange through tracheal tubes
mandibles (jaws)
They are capable of everting their stomach through their mouth - either dumping the contents or digesting something outside of its body
They are capable of everting their stomach through their mouth - either dumping the contents or digesting something outside of its body
Echinoderms
Coelomates
Deuterostomes
Radial Symmetry
Echinoderms
Coelomates
Deuterostomes
Radial Symmetry
Echinoderms have water entering into a madreporite down a water vascular system that operates tube feet
Echinoderms have water entering into a madreporite down a water vascular system that operates tube feet
• The phylum Chordata includes three subphyla, the vertebrates and two phyla of invertebrates, the urochordates and the cephalochordates.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 34.1
• Although chordates vary widely in appearance, all share the presence of four anatomical structures at some point in their lifetime.– These chordate
characteristics are a notochord; a dorsal, hollow nerve cord; pharyngeal slits; and a muscular, postanal tail.
1. Four anatomical features characterize the phylum Chordata
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 34.2
Ectoderm will invaginate to form the spinal cord and brain
Ectoderm will invaginate to form the spinal cord and brain
Cells from the neural crest may form bone and cartilage of the skull
Cells from the neural crest may form bone and cartilage of the skull
Notochord will evolve into the vertebrae of the backbone
Notochord will evolve into the vertebrae of the backbone
SuperClass Agnatha
Brain and cranium evolved
notochord will evolve into vertebrae of backbone
Jawless fish - mud suckers, suspension feeders or parasitic
no paired fins
include lamprey and hagfish
SuperClass Agnatha
Brain and cranium evolved
notochord will evolve into vertebrae of backbone
Jawless fish - mud suckers, suspension feeders or parasitic
no paired fins
include lamprey and hagfish
Jaws and paired fins were major evolutionary breakthroughsJaws evolved from a pair of gill support bars
A jawed fish can exploit food supplies that were unavailable to earlier agnathans
Jaws and paired fins were major evolutionary breakthroughsJaws evolved from a pair of gill support bars
A jawed fish can exploit food supplies that were unavailable to earlier agnathans
The Devonian period (about 360 to 400 million years ago) has been called the “age of fishes”.
Chondircthyes
Sharks and rays have cartilaginous endoskeleton
Jaws gill slits paired fins
The intestine of shark is a spiral valve, a corkscrew-shaped ridge that increases surface area and prolongs the passage of food along the short digestive tract.
The lateral line system, a row of microscopic organs sensitive to pressure changes, can detect low frequency vibrations
Chondircthyes
Sharks and rays have cartilaginous endoskeleton
Jaws gill slits paired fins
The intestine of shark is a spiral valve, a corkscrew-shaped ridge that increases surface area and prolongs the passage of food along the short digestive tract.
The lateral line system, a row of microscopic organs sensitive to pressure changes, can detect low frequency vibrations
•The ancestors of Chondrichthyes had bony skeletons.
•The cartilaginous skeleton evolved secondarily.
Osteichthyes
Bony or calcified endoskeleton with skull (During the development of most vertebrates, the skeleton is first cartilaginous and then becomes ossified as hard calcium phosphate matrix replaces the rubbery matrix of cartilage)
operculum covers the gills
swim bladder controls the bouyancy swim bladder evolved from balloonlike lungs that may have been used to breath air when dissolved oxygen levels were low in stagnant shallow waters
ray finned fish, lobe finned fish, lung fish
Osteichthyes
Bony or calcified endoskeleton with skull (During the development of most vertebrates, the skeleton is first cartilaginous and then becomes ossified as hard calcium phosphate matrix replaces the rubbery matrix of cartilage)
operculum covers the gills
swim bladder controls the bouyancy swim bladder evolved from balloonlike lungs that may have been used to breath air when dissolved oxygen levels were low in stagnant shallow waters
ray finned fish, lobe finned fish, lung fish
•Traditionally, all bony fishes were combined into a single class, Osteichthyes, but most systematists now recognize three extant classes: the ray-finned fishes, the lobe-finned fishes, and the lungfishes.
Amphibians adaptations for terrestrial living included
hard endoskeleton for support
a three chambered heart for more efficient circulation
lungs for breathing air legs for movement on land
They are not true terrestrial organisms because:
the sideward limbs (not under body) did not support their weight
their skin dried out and their gametes and eggs dried out
Amphibians adaptations for terrestrial living included
hard endoskeleton for support
a three chambered heart for more efficient circulation
lungs for breathing air legs for movement on land
They are not true terrestrial organisms because:
the sideward limbs (not under body) did not support their weight
their skin dried out and their gametes and eggs dried out
The amnion provides a protective fluid environment for the embryo to develop in
Reptiles can lay eggs in very dry environments
The amnion provides a protective fluid environment for the embryo to develop in
Reptiles can lay eggs in very dry environments
An ancestral amniote gave rise to Reptiles, Aves and Mammals
An ancestral amniote gave rise to Reptiles, Aves and Mammals
Aves probably arose from a reptile
Aves probably arose from a reptile
Reptiles are true terrestrial organisms because they have:
scales on their skin to prevent dessication
internal fertilization
leathery or hard shell to prevent the eggs from drying out
amniotic eggs
Reptiles are true terrestrial organisms because they have:
scales on their skin to prevent dessication
internal fertilization
leathery or hard shell to prevent the eggs from drying out
amniotic eggs
Low pressure to body
High
Mammalian Characteristics• Evolved from
therapsids• Hair (made of keratin)• Mammary Gland• Endothermic (active)• diaphragm• 4 chambered
heart/high metabolism • most placental
Evolutionary Trends from Ape To Humans• Jaw became shorter and teeth
smaller• Point of attachment of the
vertebra to the cranium shifted from the rear to the bottom-for bipedal walking
• Braincase became larger• Feet Flattened and arch
developed• Big toe moved in line• Reduced Size Differences
Between the Sexes. In hominoids, a size difference between females and males is a major feature of sexual dimorphism.
Evolutionary Trends from Ape To Humans
• Eyebrow ridges and other keels on the skull were reduced
• Nose becomes more prominent
• Arms become shorter