Download invertebrates

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Sylvia S. Mader
Immagini e
concetti
della biologia
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
A11 - Animal
evolution
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Kingdom Animalia
The kingdom Animalia includes all multicellular
eukaryotic organisms.
Animals are heterotrophic for ingestion, must acquire
nutrients form an external source.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Kingdom Animalia
Animals normally reproduce sexually and undergo
developmental stages that produce specialized tissues
and organs.
Frog developmental stage from zygote to tadpole
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Animals have a Protistan ancestor
The “Colonial flagellate hypothesis” states that
animals evolved from flagellated protists that lived in
colonies.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Animals derived characters
Animals have a bilateral or radial symmetry.
Bilateral: only one longitudinal plane cut the body in
two identical pieces.
Radial: Several longitudinal planes produce roughly
identical pieces.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Evolutionary tree
Animals traditional
evolutionary tree is
based on the seven
key traits of the
structure.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
The body cavity
The body cavity is a fluid-filled space, called coelom,
located between the epidermis and the gut cavity,
where internal organs develop.
•Coelomate Animals: most bilateral animals
•Pseudocoelomates: have a “false body cavity”
•Acoelomates: have no body cavity
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The body cavity
Coelomates divide into protostomes or deuterostomes,
based on the embryonic development.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Coelomate animals
A blastopore is an
opening into the digestive
tract during the
embryonic stages.
Blastopore
anus
mouth
mouth
anus
The difference between protostomes and deuterostomes
depends on the position the mouth develops in relation to
the blastopore.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Coelomate animals
Coelom
Some advantages of coelom:
•independent movement of the
body
•space for complex organs
•storage area for eggs and sperm
•protection from mechanical
shocks
•support
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Vertebrates and invertebrates
Animals are further divided into:
•INVERTEBRATES without an endoskeleton
of cartilage or bone (i.e. sponges and
mollusks).
•VERTEBRATES those that have an
endoskeleton (i.e. fish and mammals).
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Invertebrates: Porifera
The simplest animals are the sponges, multicellular
filter feeders that lack organized tissues.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Invertebrates: Cnidaria
Cnidarians are mostly sessile marine animals with
radial symmetry and a sac body plan.
Tissue level of organization.
Two body stages: polyp
(sessile) and medusa (free
moving).
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Invertebrates: Platyhelminthes
In flatworms appears bilateral symmetry. They are
parasites of humans and other animals.
•Three germ layers
•Acoelomates
•Ladder like nervous system
•Incomplete digestive tract
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Invertebrates: Nematoda
Roundworms are non segmented, show a complete
digestive tract and have a pseudocoelom.
Some nematodes as Ascaris are endoparasites of
humans.
Ascaris
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Invertebrates: Annelida
In annelids, rings encircle the body
and septa divide the coelom. The
phylum includes Polychaetes,
earthworms and leeches.
Mouth
Brain
Coelom
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Invertebrates: Mollusca
Mollusk have a three parts body plan: mantle, visceral
mass and foot. The mantle can secrete a shell.
Mollusks are divided into:
1.Gastropods
2.Cephalopods
Mantle
3.Bivalves
Visceral
mass
Foot
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Invertebrates: Mollusca
Gastropods (stomach-foot): the foot is flattened.
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Invertebrates: Mollusca
Cephalopods (head-foot): the foot is evolved into
tentacles.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Invertebrates: Mollusca
Bivalves: the foot projects from the shell.
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Invertebrates: Arthropoda
Includes the largest number of species in the animal
kingdom.
Derived characters: external skeleton, segmented
body, jointed appendages, well developed nervous
system, metamorphosis.
The body often divided into distinct regions called head,
thorax and abdomen.
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Invertebrates: Arthropoda
CRUSTACEAN are mostly marine arthropods with a hard
exoskeleton. Have head and five pairs of walking legs.
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Invertebrates: Arthropoda
CENTIPEDES and MILLIPEDES have multiple
appendages and move efficiently on land.
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Invertebrates: Arthropoda
ARACHNIDS as spiders and scorpions have four pairs
of walking legs attached to the cephalothorax.
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Invertebrates: Arthropoda
INSECTS: mostly terrestrial, live in every environment on
Earth and are among the most highly adapted of all
animal species.
Their body is divided into head, thorax and abdomen
with three pairs of legs attached to the abdomen.
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Invertebrates: Echinodermata
Echinoderms are mostly marine animals with no head,
brain or segmentation.
adults: radial symmetry
larvae: bilateral symmetry
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Invertebrates: Echinodermata
In echinoderms a water vascular system provides
locomotion and help carry out respiratory, excretory and
circulatory functions.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Chordata
All members of the chordates have bilateral symmetry
as well as body cavity, head, digestive system and
body segmentation.
Chordates are both
VERTEBRATES and INVERTEBRATES
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Chordata
During the life cycle chordates have the following
derived characters:
•Notochord (a flexible rod that provides internal support)
•Nerve chord (or spinal chord)
•Pharyngeal pouches
•Postanal tail (after embryonic development)
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Invertebrates: Chordata
Invertebrate chordates have a notochord as adults. The
four chordate features are present in Tunicates larval
stage and in adult Lancelets.
Tunicate Ascidia
Lancelet Anfiosso
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Vertebrates
Evolutionary tree is
based on five
characters.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Vertebrates
All vertebrates have:
•Jointed endoskeleton
•Paired appendages
•Well developed coelom and viscera
•Cephalization
•A closed circulatory system
•Efficient respiratory and excretory
systems
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Vertebrates: Agnatha
Few species belong to the group of jawless fish and
some of them are parasites of bigger fish (i.e.
lamprey).
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Vertebrates: Chondrichthyes
Those fish have cartilaginous endoskeleton.
The class includes the sharks and rays.
Jaws allow fish to be predaceous.
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Vertebrates: Osteichthyes
Most of the familiar fish living today are bony fish.
Osteichthyes is divided into:
•Ray-finned fish (Actinopterygii) with swim bladder
control its buoyancy;
•Lobe-finned fish (Sarcopterygii).
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Vertebrates: Amphibia
Amphibians were the first tetrapods that could move on
land.
Have jointed limbs, eyelids, ears, a voice-producing
larynx.
Lungs, together with cutaneous respiration, help the
adults live on land.
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Vertebrates: Reptilia
Reptiles have an amniotic egg, which contains extraembryonic membranes, and can reproduce on land.
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Vertebrates: Aves
Birds have many structural adaptations for flight.
Birds are homeothermic (maintain body temperature)
and lay a hard-shelled amniotic egg.
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Vertebrates: Mammalia
Mammals nourish their young with milk produced by
mammary glands.
The presence of fur helps maintain a constant body
temperature in the homeothermic mammals.
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Sylvia S. Mader Concepts of Biology © Zanichelli editore, 2012
Vertebrates: Mammalia
Mammals are:
•Monotremes: lay hard-shelled amniotic eggs
•Marsupials: have a pouch in which the newborn
matures
•Placentals: retain their offsprings inside an uterus
until birth
Duckbill platypus (monotreme)
Killer whale (placental)
Koala (marsupial)
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