Transcript Introduction to Animals

Introduction to
animals
Introduction to
Animals
Traits
Characteristics of Animals
• 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 (Ingestion)
Support 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 Exoskeleton
Support Systems
• Worms and
echinoderms
(starfish) have
fluid-filled internal
cavities giving them
support
• Called hydrostatic
skeletons
Movement
• 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
Sponge
SEDENTARY
Chiton
MOTILE
Cheetah
Reproduction in Animals
• sexual reproduction
• Some like sponges and
earthworms are hermaphrodites
produce eggs and sperm
• may exchange sperm and NOT
fertilize their own eggs
Leeches Exchange Sperm
During Mating
leech
Mating
Reproduction in Animals
• Females of some animals
produce eggs, but the eggs
develop without being fertilized
• Called Parthenogenesis
• New offspring will be all female
occurs in some fishes, several
insects, and frogs and lizards
Parthenogenesis in the Komodo
Dragon
Female
Beetles
Mating
Courtship
Young
Male
Mating and
Mating
Behaviors
Levels of Organization
• Sponges =ONLY animals with just
cellular level
• All others show– cell, tissue, organ,
and system
• Cells may specialize (take own
different shapes and functions)
• Cells held together by cell junctions
to form tissues
Atom
Molecule
or
compound
Levels of Organization
Organ
Tissue
Organ
system
Organelle
CELL
Life begins
Organism
Invertebrate
groups
Characteristics of
Invertebrates
• Simplest animals
• greatest number of different
species
• Most aquatic (found in water)
• NO backbone
• Includes sponges, cnidarians,
flatworms, roundworms, annelids,
mollusks, arthropods, and
echinoderms
Sponge - Porifera
Osculum
of
Sponge
Sponges and
Cnidarians
20
Sea Anemone - Cnidaria
Tentacles of Sea Anemone
More Cnidarians
Brain Coral
Red jellyfish
23
Flatworms - Platyhelminthes
Marine Flatworm
Planarian
Roundworms (Nematoda) and
Segmented Worms (Annelida)
Nematode
Leech (segmented worm)
Mollusca (With and Without Shells)
snail
nautilus
scallop
sea slug
octopus
Arthropoda (insects, spiders,
crustaceans, horseshoe crab)
spider
crayfish
Horseshoe crab
Dung
beetle
Echinoderms
Sea fan (crinoid)
starfish
Brittle star
Sand dollar
Sea cucumber
Vertebrate Groups
(Phylum Chordata,
Subphylum
Vertebrata)
Vertebrata
• More complex
• backbone of vertebrae
• simplest phylum to most
complex: fish, amphibians,
reptiles, birds, and mammals
Vertebrate Backbone
Vertebrata
• endoskeletons (internal)
• Some have skeletons of
cartilage (sharks, rays, and
skates)
Bone & Cartilage in Fetus
Fish
lancelet
ray
damselfish
anglerfish
Amphibia
salamander
toad
frog
newt
Reptilia
Turtle
Snake
Lizard
Alligator
Reptiles
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Birds - Aves
hummingbird
ostrich
lovebirds
Mammalia
Body
Areas
Surfaces
•
•
•
•
•
•
Dorsal – back
Ventral – belly
Anterior –front end
Posterior –hind end
Oral surface–mouth
Aboral surface–opposite the mouth
Surfaces (Most Animals)
DORSAL
POSTERIOR
ANTERIOR
VENTRAL
Surfaces (Echinoderms)
ORAL
ABORAL
mouth
Symmetry
Body Symmetry
Body Symmetry
• Symmetry =
arrangement of body
parts around central
axis
• Asymmetry
Body Symmetry
• Radial symmetry = body parts
arranged around central point
like spokes (echinoderms)
– Most with radial symmetry are
sessile (attached) or sedentary
(move very little)
Body Symmetry
• Bilateral symmetry = divided
into equal halves
• right and left sides are mirror
images
• More complex
Body Symmetry
• bilateral symmetry, usually
motile
• anterior and posterior ends
• Show cephalization
concentration of sensory organs
on the head
Segmentation
Segmentation
• Earthworms show external
segmentation
• Humans show internal segmentation
(backbone)
• Segments may fuse (cephalothorax)
Segmentation
cephalothorax
Tissues
Tissue Development
• Zygote (fertilized egg)
undergoes rapid cell divisions
=cleavage
• Forms a hollow ball of cells
=blastula
Blastula
•The blastocoel = center cavity of
blastula with 1 germ layer
(blastoderm)
Tissue Development
Archenteron
• folds inward at one point
=Gastrulation
• opening =blastopore
blastopore
Tissue Development
• Blastopore may become mouth
(Protostome) or anus
(Deuterostome)
• Protostomes (mollusks,
arthropods, & annelids)
• Deuterostomes (echinoderms &
vertebrates)
• Some animals form a middle
germ layer called mesoderm
Embryonic Development
Germ Layers
• NOT present in sponges
• Ectoderm (outer) – forms
skin, nerves, sense
organs
• Endoderm (inner) – forms
liver and lungs
• Mesoderm (middle) –
forms muscles & other
systems
Body Layers
• All worms,
mollusks,
arthropods,
echinoderms, and
vertebrates have
three cell layers
– Ectoderm
– Endoderm
– mesoderm
Stages of Development
Larval Forms
• Animals with Indirect development
• Larva does NOT resemble adult
• Cnidarian larva = Planula
Larval Forms
• Mollusk (squid & octopus) larva
= trochophore
• Echinoderm (starfish) larva is =
Dipleurula
Metamorphosis
• Usually found in arthropods
• May be complete or incomplete
• Incomplete Metamorphosis:
egg
nymph
adult
• Complete Metamorphosis:
egg
larva
pupa
adult
Metamorphosis
COMPLETE
INCOMPLETE
Body Cavities
Coelom - Body Cavity
• Internal body cavity fully lined
with mesoderm
• Body organs suspended in this
cavity
Coelom - Body Cavity
• Acoelomate =solid bodies filled
with cells
• Ex.sponges, cnidarians, &
flatworms
Coelom - Body Cavity
• Pseudocoelomate =
(roundworms) = functional body
cavity NOT fully lined with
mesoderm
Animal Systems
Support Systems
• Spongin & spicules (sponges)
• Limestone cases (corals)
• Exoskeletons of Chitin
(arthropods)
– Must be shed or molted to grow
• Inner Calcium plates (echinoderms)
• Bone/cartilage endoskeleton
(vertebrates)
Digestive Systems
• All animals = ingestive
heterotrophs
• Gastrovascular cavity with one
opening in cnidarians &
flatworms = two-way digestive
system
Two-Way Digestion
Digestive Systems
• one-way digestive system =
mouth and an anus
• Includes annelids, arthropods, &
vertebrates
One-Way Digestion
Mouth
anus
Circulatory Systems
• Transports oxygen & nutrients
to cells
• Carries away wastes & carbon
dioxide from cells
• Sponges, cnidarians, &
flatworms do NOT have
circulatory systems
Circulatory 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)
Open
Circulation
Closed
Circulation