Kingdom Animalia
General Characteristics
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Eukaryotic
Multicellular
No cell walls
Move to find the following:
– Food
– Shelter
– Protection
– Mates
General Characteristics
(continued)
• Heterotrophs – eat other organisms for energy
– Omnivore (plants & animals)
– Carnivore (animals only)
– Herbivore (plants only)
General Characteristics
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• Digest their food
because food must be
broken down to fit
inside the cells for
metabolizing
Classification – 9 major phyla
• Porifera – animals have holes throughout their body
(Ex: Sponges)
• Cnidaria – animals with soft bodies and cnidocytes
= stinging cells (Ex: jellyfish, hydra, sea anemone,
coral)
• Platyhelminthes – flat worms (Ex: planarians,
tapeworms)
• Nematoda – round worms (Ex: heartworm,
trichinella, pin worms)
• Mollusca – mollusks (Ex: snails, slugs, clams,
oysters, octopus, squid)
• Annelida – segmented worms (Ex: earthworm &
leeches)
• Arthropoda – insects, crustaceans, arachnids
• Echinodermata – spiny skinned animals (Ex: Sea
star)
• Chordata – animals with a backbone = Vertebrates
Origin of Invertebrates
• Between 610 – 570 MYA
(millions of years ago): First
eukaryotic, MULTICELLULAR
organisms
• Most likely flat, plate-shaped
organisms with soft bodies that
absorbed nutrients from their
water environments (possibly
lived in symbiotic relationships
with photosynthetic algae)
• Bilateral symmetry and possible
segmentation
• Very little cell specialization or
body organization
The Cambrian Period
• Explosion of Animals
• Began 544 MYA
• Evolution of shells,
skeletons, and other hard
outer coverings
• More specialized cells,
tissue and the beginnings
of organ systems
• Body symmetry,
segmentation, some of
type of skeleton, anterior
& posterior ends and
appendages for specific
functions
Cladogram of Invertebrate Evolution
Phylum
Cnidaria:
Cnidarians
Phylum
Platyhelminthes:
Flatworms
Phylum
Nematoda:
Roundworms
Phylum
Mollusca:
Mollusks
Phylum
Echinodermata:
Echinoderms
Phylum
Annelida:
Annelids
Phylum
Arthropoda:
Arthropods
Radial
Symmetry
Phylum
Porifera:
Sponges
Pseudocoelom
Radial
Symmetry
Deuterostome
Development
Coelom
Protostome Development
Three Germ Layers;
Bilateral Symmetry
Tissues
Single-celled
ancestor
Phylum
Chordata:
Chordates
Multicellularity
Evolutionary Trends
Specialized Cells, Tissues & Organs
1. PORIFERA & CNIDARIA: No tissues, organs nor organ systems – just
specialized cells
Germ Layers:
Porifera (sponges) – 0
Cnidaria (jellyfish, coral, sea anemone) – 2
2. WORMS: First Appearance of Organs & Organ Systems
Germ Layers: 3
Platyhelminthes (planarians & tapeworms)
Nematoda (hookworm, heartworm, pinworm)
Annelida (earthworm & leeches)
Mollusca (snails, slugs, clams, squid, octopus)
Arthropoda (insects, arachnids, centipedes, shrimp, lobster)
Echinodermata (sea star, sand dollar)
Chordata (vertebrates)
Body Symmetry
– Asymmetry: Porifera
– Radial: Cnidaria & Echinodermata
– Bilateral: Platyhelminthes, Nematoda, Annelida, Mollusca, Arthropoda &
Chordata
Evolutionary Trends (continued)
Cephalization
– Concentration of nerve cells at the anterior end of the animal
– Evolved with bilateral symmetry
– Began with GANGLIA in WORMS
– Eventually, the evolution of the BRAIN starting in MOLLUSKS and
ARTHROPODS
Coelom (BODY CAVITY) Formation
– Evolved with the development of 3 germ layers
– ACOELOMATES: no body cavity
• PORIFERA
• CNIDARIA
• PLATYHELMINTHES (flatworms)
– PSEUDOCOELOMATES: partial body cavity
• NEMATODA (roundworms)
– COELOMATES: true body cavity
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ANNELIDA
MOLLUSCA
ARTHROPODA
ECHINODERMATA
CHORDATA
Embryology
– Protostomes (mouth before anus): SPONGES to ARTHROPODS
– Deuterostomes (anus before mouth): ECHINODERMS & CHORDATES
Body Plans
• Asymmetry = no definite shape (sponge)
• Radial Symmetry = circle body plan with
a central point (sea star, jellyfish, sand
dollar, hydra)
• Bilateral Symmetry = 2 sides of the
body are arranged in the same way; the
2 sides of the body are almost mirror
images of each other (most animals have
this type of symmetry)
Body Directions
• Dorsal side = backside of animal (darker)
• Ventral side = belly-side of animal
• Lateral = left and right side of the animal; away from
the midline
• Medial- Toward the midline
• Anterior end = head end (cephalization –
concentration of nerve cells at the anterior end of
the animal which results in the formation of a true
brain)
• Posterior end = tail end
Early Development of
Animals
• Fertilized egg = Zygote
• Zygote  Embryo
• Embryo continues to divide to become a
BLASTULA (hollow ball of cells)
• The Blastula folds creating an opening called a
BLASTOPORE = called GASTRULATION
• Blastopore leads to a tube which will become
the following:
– Protostomes: mouth- ex. earthworm
– Deuterostomes: anus- ex. echinoderms
Blastulation & Gastrulation
Germ Layers
• Endoderm (innermost germ layer): gives
rise to the lining of the digestive &
respiratory tract
• Mesoderm (middle germ layer): gives
rise to muscles, circulatory,
reproductive and excretory systems
• Ectoderm (outermost germ layer): gives
rise to sensory organs, nerves,
integumentary system (skin, hair, nails,
etc.)
Germ Layers
Porifera
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Hollow tube body plan: ACOELOMATE – no coelom
Contains pores (holes) throughout body
No tissue, organs and organ systems
Live in water
Asymmetry
As adults sponges are SESSILE – attach to one place
& do not move for the rest of its life
Filter feeders
Reproduce asexually and sexually –
HERMAPHRODITES (have both male & female
reproductive organs) – external fertilization
Water goes into pores and out the OSCULUM
Ectoderm (outside) can be made of soft, flexible
material called spongin or hard, spiky material called
spicules
Porifera Chart
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No Germ Layers
No cephalization
Acoelomate
Circulatory: Diffusion
Digestive: Filter Feeders
Nervous System: None; Produces Toxins
Excretory System- Diffusion
Reproductive: Sexually/Internal Fertilization or Asexually via
budding and gemmules
• Respiratory System: Diffusion
• Movement: Sessile as Adults
Cnidaria
• Soft bodies
• Tentacles with cnidocytes = stinging cells
• Inside each cnidocyte is a nematocyst = coiled barbed
stinger with poison
• Cnidocytes are triggered by touch
• Used to paralyze & capture prey
• Radial symmetry
• Contain tissue
• Acoelomates
• Digestive cavity that breaks down food using enzymes
• Mouth
• No circulatory/respiratory systems
• Simple nervous system called Nerve Net or Nerve
Ring
• 2 Body types – Medusa (moves) & Polyp (sessile)
• Sexually reproduce – hermaphrodites – external
fertilization
Classes of Cnidaria
• Class Hydrozoa – hydra, man of war
• Class Scyphozoa – jellyfish
• Class Anthozoa – sea anemone & coral
Cnidocyte Being Triggered
Cnidarians Chart
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Germ layers: 2
Symmetry: Radial
No Cephalization
Acoelomate
Circulatory: Diffusion
Digestive/ Feeding: 1 opening with gastrovascular cavity
Nervous: specialized cells- simple system called nerve net
Excretory: Diffusion
Reproductive: sexually/ separate sexes/external fertilizationasexually via budding
• Respiratory: Diffusion
• Movement: Medusa (moves with current) or Polyp (sessile)
Worms
• Invertebrates with soft bodies
• Bilateral symmetry
• Tissue, organs, organ systems
• 3 types:
– Flat
– Round
– Segmented
Platyhelminthes
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Platy = flat, helminthe = worm
Free-living = planarian
Parasites = tapeworm
Has the first primitive excretory
system called FLAME BULB CELLS =
removal of ammonia (urea = higher
forms of animals)
No circulatory/respiratory system –
get oxygen & nutrients thru osmosis &
diffusion
Digestive system = intestines for
digesting food
Have one opening that serves as both
mouth and anus
Sexually reproduction –
hermaphrodites – internal fertilization
Can regenerate
Examples of Flatworms
Tapeworms
Platyhelminthes Chart
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Germ layers: 3
Symmetry: Bilateral
Cephalization Present
Acoelomate
Circulatory: Diffusion- No internal transport system
Digestive/ Feeding: 1 opening with digestive cavity and pharynx
Nervous: ganglia groups of nerve cells and eyespots
Excretory: Flame cells that remove excess water and metabolize
waste (ammonia)
• Reproductive: sexually/hermaphrodites –asexually via fission
• Respiratory: Diffusion
• Movement:Turbellians use cilia to move while parasitic worms rely
on the host's circulation
Nematoda
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Round worms
Largest phylum of worms (in number)
Some free-living, some parasitic
Live in soil, fresh & salt water, animals
Has a tube within a tube body plan
Has a complete digestive tract with a
separate mouth and anus (pseudocoelom)
• No circulatory/respiratory system
• Sexual reproduction – internal fertilization
Examples
• Hookworm
• Ascaris (pinworm-live in the intestine of its
hosts)
• Trichinella (found in the muscles of pigs)
• Filarial Worms (live in blood & lymph vessels of
birds and mammals)
• Heartworm
PARASITIC ROUNDWORMS
Nematoda Chart
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Germ layers: 3
Symmetry: Bilateral
Cephalization Present
Pseudocoelomate
Circulatory: Diffusion- No internal transport system
Digestive/ Feeding: 2 openings- complete
Nervous: simple nervous system and several ganglia
Excretory: diffusion
Reproductive: sexually/individual sexes/internal fertilization
Respiratory: Diffusion
Movement:undulatory; nematodes are poor swimmers and usually
require contact with a substrate to move.
Mollusca
• Soft-bodied invertebrates that usually have shells
(valves)
• Live on land, fresh & salt water
• Bilateral symmetry
• Has a true coelom = cavity where all the organs
are held
• Common body parts:
– Mantle = thin tissue that covers soft body
– Mantle cavity = where the gills are located
– Visceral mass = coelom (gut) where all the
organs are held
– Foot = strong muscle used for movement
• 1st group of animals to have a circulatory &
respiratory system (heart & gills)
• 2 types of circulatory systems: CLOSED (vessels)
& OPEN (no vessels)
Classes of Mollusks
• Univalves or Gastropods (snails, slugs)
• Bivalves (clams, oysters, mussels,
scallops = adductor muscles of clams)
• Cephalopods (octopus, squid) – complex
nervous system – centralized with a
true brain, closed circulatory system,
stream-lined to move quickly, very
smart
Mollusca Chart
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Germ layers: 3
Symmetry: Bilateral
Cephalization Present
True Coelom
Circulatory: Slow Moving- Open and Fast Moving- Closed
Digestive/ Feeding: herbivores, omnivores, filter-feeders, detritivores,
parasites/ radulatongue with teeth
Nervous: bivalves: simple nervous system (eyespots) and octopiwell
developed brains and intelligent
Excretory:nephridia remove ammonia
Reproductive: sexually/internal or external fertilization
Respiratory: Gills (aquatic) and Mantle cavity (terrestrial)
Movement: muscular foot that it uses for movement or propulsion by
pressing water from their pallial cavity, squids move backwards through the
water like a rocket
Complex
Invertebrates
Phylum Annelida, Arthropoda &
Phylum Echinodermata
Annelida
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Segmented worms
Bilateral symmetry
Tube shaped bodies
Has a true coelom
Ex: earthworms & leeches
Complete digestive system
No respiratory system (oxygen diffuses thru skin)
Nervous system – pair of ganglia and a ventral nerve
cord
• Circulatory system – 5 aortic arches that serve as the
heart and a dorsal & ventral blood vessel (closed)
• Excretory system
• Sexually reproduces – hermaphrodites – external
fertilization
Annelida Chart
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Germ layers: 3
Symmetry: Bilateral
Cephalization Present
True Coelom
Circulatory: Closed/Dorsal and Ventral Blood Vessel
Digestive/ Feeding: 2 openings- complete order: mouth, pharynx,
esophagus, crop, gizzard, intestine and anus
Nervous: well developed, brain and several nerve cords, 2 or more sets of
eyes, sensory tentacles, statocysts
Excretory: nephridia
Reproductive: sexually/individual sexes/external fertilization/ clitellum
Respiratory: Gills (aquatic) and Diffusion across skin (terrestrial)
Movement:various muscle groups and simple appendages. They use setae
and parapodia for movement
Arthropods
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Arthro = joint; Pod = foot
All appendages are jointed
Largest phylum in the animal kingdom
Usually has 3 body sections:
– Head
– Thorax
– Abdomen
Arthropoda Chart
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Germ layers: 3
Symmetry: Bilateral
Cephalization Present
True Coelom
Circulatory: Open System
Digestive/ Feeding: herbivore, carnivore and omnivore/mouthparts vary
Nervous: well developed, brain and sense organs: eyes, taste receptors
Excretory: Malpighian Tubules/ Diffusion in aquatic arthropods
Reproductive: sexually/individual sexes/internal (terrestrial) and internal or
external (aquatic)
Respiratory: Tracheal Tubes- Grasshoppers and Book Lungs- Spiders
Movement: Jointed Appendages
Major Characteristics
(continued)
• Has an exoskeleton made of chitin which is
shed when the arthropod grows – process is
called MOLTING
• Has a coelom – gut that holds all the
organs
• Have ALL the body systems
• 5 classes
– Arachnids
– Centipedes
– Millipedes
– Crustaceans
– Insects
Class Insecta
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Able to fly
Have antennae
Compound eyes (multiple lenses)
Open circulatory system
Blood does not carry oxygen = blood is
clear
• Respiratory system = spiracles & book lungs
• Goes through Metamorphosis = change in
the body from the young to adult;
triggered by hormones
Metamorphosis
• Complete = 4 stages: Egg, Larva, Pupa, Adult
• Incomplete = 3 stages: Egg, Nymph, Adult
• Why go through this life cycle?!
– Adults and young have different homes, food
sources and predators, therefore, they will not
compete increasing their chance of survival
Echinoderms
• Echino = spiny; derm = skin
• Embryos develop like the embryo
of vertebrates =
DEUTEROSTOMES
• Internal skeleton (endoskeleton)
made of calcium plates
• Water vascular system with tube
feet that carry out its body
functions
Echinodermata Chart
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Germ layers: 3
Symmetry: Radial
No Cephalization
Deuterostome- Only Invertebrate
Circulatory: Water Vascular System
Digestive/ Feeding: carnivores tube feet
Nervous: no head/not well-developed/ nerve rings and radial nerves
Excretory: Feces released through anus and ammonia through tube feet or
skin gills
Reproductive: sexually/individual sexes/external
Respiratory: Tube feet/ water vascular system and skin gills
Movement: The water vascular system of echinoderms is responsible for
their movement and ability to clean to surfaces for long periods of time