Introduction to Animals

Major Characteristics That All Animals Share:

Kingdom Animalia * So they’ll differentiate on the phylum level
Multicellular
Heterotrophic
Eukaryotic
Lack cell walls

Different Description Types of Animals

Level of Organization
Body Cavity
Number of Tissue Layers
Segmentation
Blastopore: (Protostome or Deuterostome)
Cephalization

Levels of Organization:

1. Cells 2. Tissue

1. Diploblastic or Triploblastic 3. Organs 4. Organ systems 5. Organisms

1. Simplest animals: just specialized cells to organs to organism 2. Complex animals: Cell to tissue to organ to system to organism

1. Just because an animal is more complex than another does not make it a “better” animal. There is no such thing.

Differentiation of Germ Layers: (absent, two, or three)

During embryological development, cells begin to differentiate (activate) into three layers (called germ layers) * Endoderm: Forms digestive and respiratory systems * Mesoderm: Forms muscular, reproductive, circulatory, and excretory systems (muscles) * Ectoderm: Forms nervous and integumentary systems (skin/outer covering)
Classifications: * Diploblastic: having 2 germ layers * Triploblastic: having 3 germ layers

Formation of Body Cavity:

==Body Cavity:== fluid filled space between digestive tract and body wall

Coelem: complex animals have true body cavity completely lined with mesoderm

1. <<In coelemates the endoderm forms a circular digestive tube that is surrounded by a thin layer of muscle<<

Psuedocoelem: some invertebrates, only partially lined with mesoderm

1. <<In psuedocoelemates the endoderm forms a crescent shape digestive tube<<

Acoelomate: lack coelem between body wall and digestive tract (just a tube of flesh w/ body wall)

1. <<In acoelomates the endoderm forms a triangular digestive cavity<<

1. ==All three germ layers are present in each one (just formed differently)== 2. ==Advantage to having a body cavity: Have room for specialized organs==

Blastopore Classification

Blastopore: Opening in blastula

Zygote: fertilized egg that gives rise to blastula

Blastula: hollow ball of cells that eventually folds into itself (creating the beginning of a digestive tract)

Different Groups: * ==Protostome: blastopore gives rise to the mouth== * invertebrates * ==Deuterostome: blastopore gives rise to anus== * Chordates and echinoderms (starfish)

Body Symmetry Classification:

Radial: body parts extend outward from the center

Cnidarians and Echinodermata
Bilateral: body parts have identical left and right sides

1. Platyhelminthes, Nematoda, Annelida, Mollsuca, Arthropoda, Invertebrate Chordates, and Vertebrates

Asymmetrical: no symmetry

1. Porifera

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Segmentation: repeating parts

1. Segments can become specialized

1. Examples: legs, flippers, wings, etc. 2. Bilaterally symmetrical animals 3. Annelids (Earthworm)

Cephalization Classification:

1. concentration of sense organs and nerve cells

Invertebrates:

Invertebrate Characteristics/Overview:

Lack a backbone or vertebral column
Includes 33 phyla (largest group)

Different Phyla Include:

Phylum Porifera
Phylum Cnidarian
Phylum Arthropoda
Phylum Platyhelminthes
Phylum Nematoda
Phylum Echinodermata
Phylum Annelida
Phylum Mollusca

\ Invertebrate Phylums and Their Individual Classifications Table:

Phylum	Example(s)	Germ Layers	Symmetry	Cephalization	Early Development (Blastopore formation)
Porifera	Sponges	absent	asymmetrical	absent	none
Cnidarian	Sea Anemones	two	radial	absent	none
Platyhelminth-es	Flatworms	two	bilateral	present	protostome
Nematoda	Roundworms	three	bilateral	present	protostome
Annelida	Earthworms	three	bilateral	present	protostome
Mollusca	Snails	three	bilateral	present	protostome
Echinodermata	Starfish	three	radial	absent	deuterostome
Arthropoda (Largest Phylum)	Crabs	three	bilateral	present	protostome
}}(Not Phylum) Invertebrate Chordates}}	}}Tunicates}}	}}three}}	}}bilateral}}	}}absent}}	}}deuterostome}}
}}Vertebrates}}(Not Invertebrates)	}}Birds, Humans}}	}}three}}	}}bilateral}}	}}present}}	}}deuterostome}}

Quick Sight List:

Phylum Porifera: absent germ layers, asymmetrical, no cephalization, and no blastula rise
Phylum Cnidarians: two germ layers, radial symmetry, no cephalization, and no blatstula rise
Phylum Platyhelminthes: three germ layer, bilateral symmetry, cephalization, a protostome
Phylum Nematoda: three germ layers, bilateral symmetry, cephalization, a protostome
Phylum Annelida: three germ layers, bilateral symmetry, cephalization, a protostome
Phylum Mollusca: three germ layers, bilateral symmetry, cephalization, a protostome
Phylum Arthropoda: three germ layers, bilateral symmetry, cephalization, a protostome
Phylum Echinodermata: three germ layers, radial symmetry, no cephalization, a deuterostome
Invertebrate Chordates: three germ layers, bilateral symmetry, no cephalization, a deuterostome
Vertebrates: three germ layers, bilateral symmetry, cephalization, a protostome

\ Relationship Between Echinodermata and Chordates:

Invertebrates of the Phylum Echinodermata are the closest cousins to the chordates

Characteristics of All Chordates (that they will exhibit at some point in life):

==Dorsal hollow nerve cord==: the major cord of nerve fibers running the length of the animal’s body that can develop into the %%spinal chord%% in vertebrates
==Notochord==: supporting rod below the nerve cord that gives rise to the %%(intervebral disc)%% in vertebrates
==Tail== that extends below the anus that gives rise to the %%(tailbone)%% in vertebrates
==Pharyngeal pouches/sacs==: lateral sacs that branch from the pharynx of chordate embryos and may open outside as %%gill slits%% in adult fishes (vertebrates) and invertebrate chordates

@@Difference between Invertebrates and Vertebrates?@@

Vertebrates are just chordates that have a @@backbone@@ while invertebrates lack a backbone or vertical column

Diagrams:

Invertebrate Chordates: @@Cephalochordata@@: *

Body Wall.Body Cavity Diagrams: * \

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