Introduction to animals
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Transcript of Introduction to animals
Introduction to animals
Introduction Introduction to Animalsto Animals
TraitsTraits
Characteristics of Characteristics of AnimalsAnimals
•All multicellular (metazoans)
•Eukaryotes (cells with nucleus & organelles)
• Ingestive heterotrophs (take in food and internally digest it)
•Store food reserves in the liver as glycogen
Lions Feeding Lions Feeding (Ingestion)(Ingestion)
Support SystemsSupport Systems• Have some type of skeletal support• Endoskeleton inside and made of
cartilage &/or bone• Exoskeletons found in arthropods
– Cover the outside of the body– Limit size– Must be molted making animal
vulnerable to predators
Cicada Molting Cicada Molting ExoskeletonExoskeleton
Support SystemsSupport Systems
• Worms and echinoderms (starfish) have fluid-filled internal cavities giving them support
• Called hydrostatic skeletons
MovementMovement•Animals such as sponges may
be sessile (attached & non-moving)
•Animals that move very little are said to be sedentary (clam)
•Animals that can move are motile
•Have muscular tissue to provide energy for movement
SESSILE SEDENTARY
MOTILE
Sponge Chiton
Cheetah
Reproduction in Reproduction in AnimalsAnimals
• All animals are capable of sexual reproduction
• Some animals like sponges and earthworms are hermaphrodites producing both eggs and sperm
• Hermaphrodites may exchange sperm and NOT fertilize their own eggs
Leeches Exchange Leeches Exchange Sperm During MatingSperm During Mating
Mating
leech
Reproduction in Reproduction in AnimalsAnimals
• Females of some animals produce eggs, but the eggs develop without being fertilized
• Called Parthenogenesis• New offspring will be all
female Parthenogenesis occurs in some fishes, several kinds of insects, and a few species of frogs and lizards
Parthenogenesis in the Parthenogenesis in the Komodo DragonKomodo Dragon
Mating Mating and and
Mating Mating BehaviorsBehaviors
Beetles
Mating
Male
Female
Young
Courtship
Levels of OrganizationLevels of Organization
• Sponges are the ONLY animals that have just the cellular level
• All other animals show these levels – cell, tissue, organ, and system
• Cells may specialize (take own different shapes and functions)
• Cells are held together by cell junctions to form tissues
InvertebratInvertebrate groupse groups
Characteristics of Characteristics of InvertebratesInvertebrates
• Simplest animals• Contain the greatest number
of different species • Most are aquatic (found in
water)• Do NOT have a backbone• Includes sponges, cnidarians,
flatworms, roundworms, annelids, mollusks, arthropods, and echinoderms
Sponge - PoriferaSponge - Porifera
Osculum of
Sponge
Sea Anemone - CnidariaSea Anemone - Cnidaria
Tentacles of Sea Anemone
More CnidariansMore Cnidarians
Brain Coral
Red jellyfish
Flatworms - Flatworms - PlatyhelminthesPlatyhelminthes
Planarian
Marine Flatworm
Roundworms (Nematoda) Roundworms (Nematoda) and Segmented Worms and Segmented Worms
(Annelida)(Annelida)
Nematode Leech (segmented worm)
Mollusca (With and Without Shells)
snail scallop
nautilus nudibranch
octopus
Arthropoda (insects, spiders, crustaceans,
horseshoe crab)
Dung beetle
Horseshoe crab
crayfishspider
EchinodermsEchinoderms
Sea cucumber
Sand dollar
starfish
Brittle star
Sea fan (crinoid)
VertebratVertebrate Groupse Groups
VertebrataVertebrata
•More complex animals•Most have a backbone
made up of individual bones called vertebrae
•From simplest to most complex, the phylum includes: fish, amphibians, reptiles, birds, and mammals
Vertebrate BackboneVertebrate Backbone
VertebrataVertebrata• Vertebrates have
endoskeletons (internal)• Some vertebrates have
skeletons of cartilage (sharks, rays, and skates)
• Other vertebrates have skeletons of bone and cartilage (reptiles, birds, & mammals)
Bone & Cartilage in Bone & Cartilage in FetusFetus
FishFish
lancelet ray
anglerfish
damselfish
AmphibiaAmphibia
toad
newt
frog
salamander
ReptiliaReptilia
Turtle
Snake
Alligator
Lizard
Birds - AvesBirds - Aves
hummingbird ostric
hlovebirds
MammaliaMammalia
Body Body AreasAreas
Surfaces• Dorsal – back or upper surface• Ventral – belly or lower surface• Anterior – head or front end• Posterior – tail or hind end
opposite the head• Oral surface (echinoderms) – is
where the mouth is located (underside)
• Aboral surface (echinoderms) – is opposite the mouth (top side)
DORSAL
VENTRAL
Surfaces (Most Surfaces (Most Animals)Animals)
ANTERIOR POSTERIOR
Surfaces (Echinoderms)Surfaces (Echinoderms)
ORALABORAL
mouth
Symmetry
Body SymmetryBody Symmetry
Body SymmetryBody Symmetry
• Symmetry is the arrangement of body parts around a central plane or axis
• Asymmetry occurs when the body can’t be divided into similar sections (sponges)
Body SymmetryBody Symmetry
•Radial symmetry occurs when body parts are arranged around a central point like spokes on a wheel (echinoderms)
•Most animals with radial symmetry are sessile (attached) or sedentary (move very little)
Body SymmetryBody Symmetry
•Bilateral symmetry occurs when animals can be divided into equal halves along a single plane
•Organisms will have right and left sides that are mirror images of each other
•More complex type of symmetry
Body SymmetryBody Symmetry
• Animals with bilateral symmetry are usually motile
• Animals have an anterior and posterior ends
• Show cephalization (concentration of sensory organs on the head or anterior end)
Segmentation
SegmentationSegmentation• Occurs whenever animal bodies
are divided into repeating units or segments
• Found in more complex animals• Earthworms show external
segmentation• Humans show internal
segmentation (backbone)• Segments may fuse
(cephalothorax)
SegmentationSegmentation
cephalothorax
TissueTissuess
Tissue DevelopmentTissue Development
• Zygote (fertilized egg) undergoes rapid cell divisions called cleavage
• Forms a hollow ball of cells called the blastula
BlastulaBlastula•The blastocoel is the center cavity of the blastula with 1 germ layer (blastoderm)
Tissue DevelopmentTissue Development• The blastula
INVAGINATES (folds inward at one point)
• • Called
Gastrulation
• The center is the primitive gut or Archenteron blastopore
Archenteron
Embryonic Embryonic DevelopmentDevelopment
Germ LayersGerm Layers• Form tissues,
organs, & systems• NOT present in
sponges• Ectoderm (outer) –
forms skin, nerves, sense organs
• Endoderm (inner) – forms liver and lungs
• Mesoderm (middle) – forms muscles & other systems
Body LayersBody Layers•Sponges have NO tissues or organs, only specialized cells
•Cnidarians like jellyfish & coral have only two body layers & one body opening (mouth/anus) into gastrovascular cavity
Body LayersBody Layers
• All worms, mollusks, arthropods, echinoderms, and vertebrates have three cell layers– Ectoderm– Endoderm– mesoderm
Embryonic Embryonic CleavageCleavage
CleavageCleavage• Cleavage – rapid
mitosis (cell division) of zygote
• Radial Cleavage – cells divide parallel or perpendicular to axis to each other
CleavageCleavage• Spiral Cleavage –
cellular divisions occur diagonally, in a twisting pattern
Stages of Development
Larval FormsLarval Forms• Animals with Indirect
development• Go through immature (larval)
forms• Larva does NOT resemble
adult• Cnidarian (jellyfish, coral, &
sea anemone) larva called Planula
Larval FormsLarval Forms•Mollusk (squid & octopus)
larva called trochophore•Echinoderm (starfish) larva
is called Dipleurula
MetamorphosisMetamorphosis
•Usually found in arthropods•May be complete or
incomplete• Incomplete Metamorphosis: egg nymph adult•Complete Metamorphosis: egg larva pupa adult
MetamorphosisMetamorphosis
COMPLETE INCOMPLETE
Body Body CavitiesCavities
Coelom - Body CavityCoelom - Body Cavity• Internal body cavity fully
lined with mesoderm•Body organs suspended in
this cavity
Coelom - Body CavityCoelom - Body Cavity• Acoelomate animals have
solid bodies filled with cells• Acoelomate animals include
sponges, cnidarians, & flatworms
Coelom - Body CavityCoelom - Body Cavity
•Pseudocoelomate animals (roundworms) have a functional body cavity NOT fully lined with mesoderm
Animal SystemsAnimal Systems
Support SystemsSupport Systems• Spongin & spicules (sponges)• Limestone cases (corals)• Exoskeletons of Chitin
(arthropods)– Must be shed or molted to grow
• Inner Calcium plates or Test (echinoderms)
• Bone/cartilage endoskeleton (vertebrates)
Digestive SystemsDigestive Systems•All animals are ingestive
heterotrophs•Choanocytes (specialized
cells) capture & digest food for sponges
•Gastrovascular cavity with one opening in cnidarians and flatworms for food to enter & leave; called two-way digestive system
Two-Way DigestionTwo-Way Digestion
Digestive SystemsDigestive Systems• Animals with a one-way
digestive system have a mouth and an anus
• Food enters the mouth, continues in one direction through the digestive tract, and wastes leave through the anus
• Includes annelids, arthropods, & vertebrates
One-Way DigestionOne-Way Digestion
Mouth
anus
Circulatory SystemsCirculatory Systems
•Transports oxygen & nutrients to cells
•Carries away wastes & carbon dioxide from cells
•Sponges, cnidarians, & flatworms do NOT have circulatory systems
Circulatory SystemsCirculatory Systems
• In closed circulation, blood remains inside blood vessels until it reaches cells (annelids & vertebrates)
• In open circulation, blood is pumped out of blood vessels to bathe tissues in the body cavity or hemocoel (arthropods & mollusks)