Exam 3 Review - Animal Classification and Anatomy

Exam 3 Review Overview

• Key areas of focus include organisms' classification, anatomical terms, major phyla characteristics, and physiological systems.

Taxonomic Hierarchy

• Levels: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

• Domains: Bacteria, Archaea, Eukarya (includes Protista, Fungi, Plants, Animals).

Classification of Animals

• Features for Classification:

  • Organization

  • Morphology

  • Development

• Morphology: Refers to the shape and structure of organisms.

  • Symmetry Types:

    • Asymmetrical (e.g., amoeba)

    • Radial (e.g., starfish)

    • Bilateral (e.g., lobster)

Embryonic Development

• Animals classified based on embryonic germ layers:

  • Germ Layers:

    • Ectoderm (outer layer): forms skin and nervous tissue.

    • Endoderm (inner layer): forms digestive tract.

    • Mesoderm (middle layer): found in some species, forms muscles and internal organs.

Anatomical Terminology

• Directional Terms:

  • Anterior (front), Posterior (rear)

  • Superior (top), Inferior (bottom)

  • Cephalic (head), Caudal (tail)

Body Plan Types

Protostomes vs Deuterostomes

• Protostomes: Mouth develops from the blastopore (e.g., annelids, mollusks).

• Deuterostomes: Anus develops from the blastopore (e.g., chordates, echinoderms).

Coelom Types

• Coelom: Body cavity surrounded by mesoderm.

  • Types:

    • Coelomate (true coelom)

    • Pseudocoelomate (one side mesoderm, one side endoderm)

    • Acoelomate (no body cavity)

Phylum Descriptions

Phylum Porifera (Sponges)

• Simplest animals, no true tissues.

• Specialized cells (e.g., choanocytes) for filtration.

• Skeleton composed of

  • Spongin: Soft protein fibers.

  • Spicules: Simple mineral structures.

• Reproduction:

  • Asexual (budding, fragmentation)

  • Sexual (sperm and egg production)

• Body forms:

  • Ascon, Sycon, Leucon (complexity increases).

Phylum Cnidaria

• Characteristics:

  • Specialized stinging cells (cnidocytes).

  • Radial symmetry, diploblastic (two tissue layers).

• Body forms:

  • Polyps (sessile)

  • Medusa (free swimming)

• Classes include:

  • Hydrozoa (Hydra)

  • Scyphozoa (jellyfish)

  • Anthozoa (corals, sea anemones)

Phylum Mollusca

• Basic Characteristics:

  • Triploblastic, bilateral symmetry.

  • Open circulatory system containing hemolymph.

  • Three body parts: visceral mass, mantle, foot.

• Classes include:

  • Bivalvia (clams, mussels)

  • Gastropoda (snails, slugs)

  • Cephalopoda (squids, octopuses)

• Bivalvia: Two-part hinged shell, filter feeders.

• Gastropoda: Usually possess shells, muscular foot for locomotion.

• Cephalopoda: Highly organized, complex sense organs.

Phylum Platyhelminthes (Flatworms)

• Characteristics:

  • Acoelomates, dorsoventrally flattened.

  • Incomplete digestive system.

• Classes:

  • Turbellaria (free-living)

  • Monogenea (ectoparasites)

  • Trematoda (internal parasites)

  • Cestoda (tapeworms).

Phylum Annelida (Segmented Worms)

• Characteristics:

  • True segmentation, complete digestive system.

  • Closed circulatory system.

• Classes:

  • Oligochaeta (earthworms)

  • Polychaeta (clam worms).

Phylum Arthropoda

• Characteristics:

  • Exoskeleton made of chitin.

  • Compound eyes, jointed appendages.

  • Open circulatory system.

• Subphyla:

  • Chelicerata (spiders, scorpions)

  • Crustacea (crabs, lobsters)

  • Myriapoda (millipedes, centipedes)

  • Hexapoda (insects).

Phylum Echinodermata

• Characteristics:

  • Pentradial symmetry, water vascular system.

  • Examples include sea stars and sea urchins.

Phylum Chordata

• Key Features (at some life stage):

  • Notochord, dorsal hollow nerve cord, pharyngeal slits, post-anal tail.

• Subphyla include:

  • Cephalochordata (lancelets)

  • Urochordata (tunicates)

  • Vertebrates (fish, amphibians, reptiles, birds, mammals).

Circulatory Systems

• Types of Systems:

  • Simple Circulatory Systems (e.g., Porifera & Cnidaria): rely on diffusion.

  • Open Circulatory Systems (e.g., Arthropoda): hemolymph circulates.

  • Closed Circulatory Systems (some annelids, most vertebrates): heart pumps blood through vessels.

• Heart Structure Varies:

  • Fish: 2 chambers

  • Amphibians & reptiles: 3 chambers

  • Birds & mammals: 4 chambers.

Respiratory Systems

• Mammals: tidal respiration.

• Birds: unidirectional airflow for efficiency.

• Arthropods: spiracles lead to trachea for gas exchange directly to tissues.

Osmoregulation

• Freshwater Fish: gain water and lose salts.

• Saltwater Fish: lose water and gain salts due to external environment pressures.

Exam 3 Review Overview

Key areas of focus include organisms' classification, anatomical terms, major phyla characteristics, and physiological systems.

Taxonomic Hierarchy

Levels: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

Domains: Bacteria, Archaea, Eukarya (includes Protista, Fungi, Plants, Animals).

Classification of Animals

Features for Classification:

• Organization

• Morphology

• Development

Morphology: Refers to the shape and structure of organisms.

Symmetry Types:

• Asymmetrical (e.g., amoeba)

• Radial (e.g., starfish)

• Bilateral (e.g., lobster)

Embryonic Development

Animals classified based on embryonic germ layers:

Germ Layers:

• Ectoderm (outer layer): forms skin and nervous tissue.

• Endoderm (inner layer): forms digestive tract.

• Mesoderm (middle layer): found in some species, forms muscles and internal organs.

Anatomical Terminology

Directional Terms:

• Anterior (front), Posterior (rear)

• Superior (top), Inferior (bottom)

• Cephalic (head), Caudal (tail)

Body Plan Types

Protostomes vs Deuterostomes

• Protostomes: Mouth develops from the blastopore (e.g., annelids, mollusks).

• Deuterostomes: Anus develops from the blastopore (e.g., chordates, echinoderms).

Coelom Types

Coelom: Body cavity surrounded by mesoderm.
Types:

• Coelomate (true coelom)

• Pseudocoelomate (one side mesoderm, one side endoderm)

• Acoelomate (no body cavity)

Phylum Descriptions

Phylum Porifera (Sponges)

• Simplest animals, no true tissues.

• Specialized cells (e.g., choanocytes) for filtration.

• Skeleton composed of

  • Spongin: Soft protein fibers.

  • Spicules: Simple mineral structures.

• Reproduction:

  • Asexual (budding, fragmentation)

  • Sexual (sperm and egg production)

• Body forms:

  • Ascon, Sycon, Leucon (complexity increases).

Phylum Cnidaria

Characteristics:

• Specialized stinging cells (cnidocytes).

• Radial symmetry, diploblastic (two tissue layers).

• Body forms:

  • Polyps (sessile)

  • Medusa (free swimming)

• Classes include:

  • Hydrozoa (Hydra)

  • Scyphozoa (jellyfish)

  • Anthozoa (corals, sea anemones)

Phylum Mollusca

Basic Characteristics:

• Triploblastic, bilateral symmetry.

• Open circulatory system containing hemolymph.

• Three body parts: visceral mass, mantle, foot.

• Classes include:

  • Bivalvia (clams, mussels)

  • Gastropoda (snails, slugs)

  • Cephalopoda (squids, octopuses)

• Bivalvia: Two-part hinged shell, filter feeders.

• Gastropoda: Usually possess shells, muscular foot for locomotion.

• Cephalopoda: Highly organized, complex sense organs.

Phylum Platyhelminthes (Flatworms)

Characteristics:

• Acoelomates, dorsoventrally flattened.

• Incomplete digestive system.

• Classes:

  • Turbellaria (free-living)

  • Monogenea (ectoparasites)

  • Trematoda (internal parasites)

  • Cestoda (tapeworms).

Phylum Annelida (Segmented Worms)

Characteristics:

• True segmentation, complete digestive system.

• Closed circulatory system.

• Classes:

  • Oligochaeta (earthworms)

  • Polychaeta (clam worms).

Phylum Arthropoda

Characteristics:

• Exoskeleton made of chitin.

• Compound eyes, jointed appendages.

• Open circulatory system.

• Subphyla:

  • Chelicerata (spiders, scorpions)

  • Crustacea (crabs, lobsters)

  • Myriapoda (millipedes, centipedes)

  • Hexapoda (insects).

Phylum Echinodermata

Characteristics:

• Pentaradial symmetry, water vascular system.

• Examples include sea stars and sea urchins.

Phylum Chordata

Key Features (at some life stage):

• Notochord, dorsal hollow nerve cord, pharyngeal slits, post-anal tail.

• Subphyla include:

  • Cephalochordata (lancelets)

  • Urochordata (tunicates)

  • Vertebrates (fish, amphibians, reptiles, birds, mammals).

Circulatory Systems

Types of Systems:

• Simple Circulatory Systems (e.g., Porifera & Cnidaria): rely on diffusion.

• Open Circulatory Systems (e.g., Arthropoda): hemolymph circulates.

• Closed Circulatory Systems (some annelids, most vertebrates): heart pumps blood through vessels.

Heart Structure Varies:

• Fish: 2 chambers

• Amphibians & reptiles: 3 chambers

• Birds & mammals: 4 chambers.

Respiratory Systems

• Mammals: tidal respiration.

• Birds: unidirectional airflow for efficiency.

• Arthropods: spiracles lead to trachea for gas exchange directly to tissues.

Osmoregulation

Freshwater Fish: gain water and lose salts.

Saltwater Fish: lose water and gain salts due to external environment pressures.

Mnemonic Tool - Monmophonics:

• Monophyletic: A group consisting of an ancestor and all its descendants.

• Paraphyletic: A group that includes an ancestor and some, but not all, of its descendants.

• Polyphyletic: A group that does not include the most recent common ancestor of its members, typically made up of unrelated organisms.

The rhyming structure of "monmophonics" can help you recall the classification of groups based on their common ancestry.