earland1 the big picture. earland2 draw this on a blank sheet
TRANSCRIPT
Part A – Animal Characteristics
DEFINING CHARACTERISTCS OF ANIMALS1. Heterotrophs: ingest their food2. Multicellular: 3. Eukaryotic: animal cells with a nucleus and organelles – large diversity of cell specialization4. No cell walls TWO MAIN DIVISIONS:
Invertebrate: all other phyla without internal skeletons
Vertebrate: Phylum Chordate – internal skeleton
Cephalization Cephalization is considered an evolutionary trend,
whereby nervous tissue, over many generations, becomes concentrated toward one end of an organism. This process eventually produces a head region with sensory organs.
Cephalization is intrinsically connected with a change in symmetry. It accompanied the move to bilateral symmetry made in flatworms, with ocelli and pinnae placed in the head region.
In addition to a concentration of sense organs, all animals from annelids on also place the mouth in the head region.
This process is also tied to the development of an anterior brain in the chordates from the notochord.
A notable exception to the trend of cephalization throughout evolutionary advancement is phylum Echinodermata, which have Pentamerous Radial Symmetry – Echinoderm Adults only
Symmetry
None – Porifera
Radial – Cnidaria
Bilateral – All others
› Pentamerous Radial Symmetry – Echinoderm Adults only
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Tissue Layers
• Endoderm - digestion and respiration structures
• Mesoderm - muscles, bones, blood, and reproductive organs
• Ectoderm - skin, brain, and nervous system
Tissue Layers
None – Porifera
Diploblastic – Cnidaria endoderm & Ectoderm with mesoglea between
Triploblastic – All others Endoderm, Mesoderm, Ectoderm
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Development of a Coelom
Diploblastic Acoelomate – Cnidaria
Triploblastic Acoelomates – Platyhelminthes
Pseudocelomate – Nematoda
Coelomates – Annedlida and everything above
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The Acoelomates
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DigestiveCavity
DigestiveLining
SolidTissue
Body Wall
No cavity between body wall & digestive tract
Cnidaria
The Pseudocoelomates
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Digestive Cavity
Digestive Tract
Pseudocoelom
Body Wall
Body cavity partially lined with mesoderm
Partial Lining
Nematoda
The True Coelomates
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Digestive Cavity
Digestive Tract
Coelom
Body Wall
Body cavity completely lined with mesoderm
Complete Lining
Annelida
Embryological Development
Bilateral animals can be divided into two main groups based on embryological development
Protostomes› Body cavity forms within a space between the body
wall and the digestive cavity› Blastopore becomes mouth› e.g. nematodes, arthropods, flatworms, annelids,
mollusks Deuterostomes
› Body cavity forms as an outgrowth of the digestive cavity
› Blastopore becomes anus› e.g. echinoderms, chordatesEarland 15
Protostome vs Deuterostome
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Protostome
•Coelom forms from the solid masses in the embryo•blastopore becomes the mouth
• spiral / determinate cleavage
• mosaic development
(Annelida, Arthropoda, Mollusca,)
Deuterostome
• Coelom forms from a portion of the digestive tube•blastopore becomes the anus
• radial / indeterminate cleavage
• regulative development
(Echinodermata, Chordata)
Reproduction
5. Reproduction: Asexual and sexual A. Direct development: “Babies”
(offspring) look like adults (they get bigger as they get older, but don’t change)
B. Indirect development: Metamorphosis Ex) Tadpole to frog
Feeding
Herbivores: Eats plants Carnivores : Eats animals Omnivores : Eats plants and animals Parasites : Lives off of a host Filter Feeders : Strains floating plants and
animals from surrounding water Detrivores : Feeds on decaying plants and
animals (detrius)
The 7 Essentials
Feeding – see above Respiration – skin or full system Internal Transport – closed or open
circulation Excretion – waste removal Response – nerve cells – brain-
specialized organs Movement – exo or endoskeleton,
muscles Reproduction – sexual or asexual
Sponges_Phylum Porifera
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Sponges_Phylum PoriferaKey Ideas
Simplest Animal - Commonly referred to as Sponges
Adults are sessile- can’t move on their own
Lack true tissues and organs, most are unspecialized – Cell Level of Organization
Incomplete digestive system No Symmetry Ancient & mostly marine Close to 5,000 species divided into 3
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Porifera
Outer layer protects the interior and has many holes through which water can enter the sponge
Inner layer are lined with collar cells, which have flagella
Amoebocytes wander through the jelly-like material and pick up food from the collar cells for digestions, transport oxygen, dispose of waste and can change into other cells for support
Have special chemical defenses to protect from predators, disease organisms, humans use these chemicals
Related closely to protists and are the earliest animals.
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Porifera Cell Types
Porocytes: water goes thru them into central cavity
Collar Cells: move water current thru the pores via flagella
Osculum: opening that water exits cavity thru Spicules: form skeleton
Some sponges have skeletons made by both CaCO3 and SiO2.
Amebocytes: build the spicules
Note: water flow = nutrients in and waste out
Feeding
Filter Feeders! Sponges are characterized by the possession of a
feeding system unique among animals. Poriferans don't have mouths; instead, they have tiny pores in their outer walls through which water is drawn. Cells in the sponge walls filter goodies from the water as the water is pumped through the body and out other larger openings. The flow of water through the sponge is unidirectional, driven by the beating of flagella which line the surface of chambers connected by a series of canals. Sponge cells perform a variety of bodily functions and appear to be more independent of each other than are the cells of other animals.
Reproduction
Sexual: - sperm are release into the water thru pores amebocytes carry to eggs zygote larvae swim & settle new sponge
Asexual: Gemmules: sphere of amebocytes &
spicules that can survive freezing or drying
Budding: part falls off new sponge
Phylum Cnidaria
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Phylum Cnidaria: the hydra, anemones, & jellyfish – Radial symmetry
› Tissue Level of Organization - Cells organized into distinct tissues
› Rudimentary nerve network and contractile tissue› No true organs› Incomplete Digestive System - One digestive
opening › Reproduce sexually and asexually
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Cnidarians- Con’t
Radial symmetry, most do not have a head and are sessile
Tentacles with stinging cells called cnidocytes
Has poisonous barbs called nematocysts, that fire when touched, once prey has been captured, the tentacles move it to the gastovascular cavity
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Two forms Polyp-cylindrical
body with tentacles radiating from one end, sessile
Medusa- umbrella shaped form with fringed tentacles on the lower edge, move freely
Some cnidarians exist in both forms and some one or the other
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