Animal Diversity and Anatomy: Study Guide for Bio 2 Final

Opisthokonta

Taxonomic Grouping and Key Organisms

Opisthokonta is a broad eukaryotic clade that includes animals, fungi, and several related protists. Understanding this group is essential for recognizing evolutionary relationships among major life forms.

• Key Members: Animals, fungi, and choanoflagellates.

• Choanoflagellates: Single-celled or colonial protists considered the closest living relatives of animals. Their collar cells resemble sponge cells, supporting the evolutionary link.

• Relationship to Animals: Choanoflagellates share structural similarities with sponge choanocytes, suggesting a common ancestor.

Fungi, Parazoa, & Radiata

Fungi: Anatomy and Symbiosis

Fungi are a diverse kingdom characterized by their mode of nutrition and reproductive structures. Basidiomycota, a major fungal phylum, forms fruiting bodies known as basidiocarps.

• Basidiomycota Anatomy: Fruiting body includes cap, gills, stipe, and spores.

• Symbiosis: Many fungi form mutualistic relationships with plants (mycorrhizae), enhancing nutrient uptake.

• Lichens: Composite organisms formed by a symbiotic association between a fungus and a photosynthetic partner (algae or cyanobacteria).

• Lichen Growth Forms: Crustose (flat), foliose (leafy), and fruticose (branching).

Parazoa and Radiata: Basic Anatomy

• Parazoa: Includes sponges, which lack true tissues but possess specialized cells.

• Radiata: Includes cnidarians (e.g., jellyfish), characterized by radial symmetry and specialized stinging cells (cnidocytes).

Metazoa

Sponges and Classification

Metazoa encompasses all multicellular animals. Sponges (Phylum Porifera) are basal metazoans with simple body plans.

• Generalized Anatomy: Sponges have pores (ostia), a central cavity (spongocoel), and an osculum for water exit.

• Classification: Based on body structure and cell types; rationale includes evolutionary relationships and functional adaptations.

Lophotrochozoa

Anatomy and Classification

Lophotrochozoa is a superphylum of protostome animals, including annelids, mollusks, and platyhelminthes. Classification relies on anatomical features and developmental patterns.

• Key Anatomical Structures: Lophophore (feeding structure), trochophore larva.

• Tapeworm Anatomy: Scolex (head), proglottids (segments).

• Earthworm Anatomy: Segmented body, clitellum, setae.

• Squid Anatomy: Mantle, siphon, tentacles, ink sac.

Squid Dissection: Female Anatomy

The female squid displays distinct reproductive and anatomical features.

• Key Structures: Mantle, siphon, gills, nidamental gland, ovary, ink sac, funnel retractor muscle.

Ecdysozoa

Anatomy and Classification

Ecdysozoa includes arthropods and nematodes, characterized by molting (ecdysis) of their exoskeleton.

• Horseshoe Crab Anatomy: Carapace, telson, walking legs.

• Crayfish Anatomy: Segmented body, claws, antennae, uropod, telson, carapace, abdomen.

• Grasshopper Anatomy: Head, thorax, abdomen, wings, legs.

• Insecta vs. Other Ecdysozoans: Insects have three body segments and six legs; other arthropods may differ in segmentation and appendages.

• Chilopoda vs. Diplopoda: Chilopoda (centipedes) have one pair of legs per segment; Diplopoda (millipedes) have two pairs per segment.

Crayfish Dissection: External Anatomy

The crayfish is a representative arthropod, with distinct external features used for classification and identification.

• Key Structures: Carapace, abdomen, telson, uropod, walking legs, claws, antennae, antennule, rostrum, eye.

Deuterostomia

Chordates and Mammals

Deuterostomia includes chordates and echinoderms, defined by embryonic development and shared anatomical features.

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

• Mammal Characteristics: Hair, mammary glands, endothermy, differentiated teeth.

• Sea Star Anatomy: Arms, central disc, tube feet, madreporite, ampullae, water vascular system.

• Sea Star Cellular Development: Includes stages such as fertilization, cleavage, blastula, gastrula.

• Chordate Classes: Major classes include fish, amphibians, reptiles, birds, and mammals; each with unique adaptations.

• Mammalian Dentition: Differentiated teeth (incisors, canines, premolars, molars) for specialized feeding.

Representative Examples and Lab Identification

Specimen Identification and Structures

Students should be able to identify representative examples from each phylogenetic group and recognize key anatomical structures from dissections.

• Lab Manual Specimens: Includes crayfish, squid, sea star, earthworm, tapeworm, horseshoe crab, grasshopper.

• Dissection Skills: Recognize and label anatomical features in lab specimens.

Squid Dissection: Male Anatomy

The male squid displays reproductive organs and internal structures relevant to cephalopod biology.

• Key Structures: Mantle, siphon, gills, ink sac, funnel retractor muscle.

Summary Table: Major Animal Groups and Key Features

This table summarizes the main animal groups discussed and their distinguishing characteristics.

Group	Key Features	Representative Example
Opisthokonta	Includes animals, fungi, choanoflagellates	Choanoflagellate, sponge
Fungi	Basidiocarps, symbiosis, lichen	Mushroom, lichen
Parazoa	No true tissues, specialized cells	Sponge
Radiata	Radial symmetry, cnidocytes	Jellyfish
Lophotrochozoa	Lophophore, trochophore larva	Earthworm, squid
Ecdysozoa	Molting, segmented body	Crayfish, grasshopper
Deuterostomia	Notochord, water vascular system	Sea star, mammal

Key Terminology

• Opisthokonta: Eukaryotic clade including animals and fungi.

• Choanoflagellate: Protist closely related to animals.

• Basidiomycota: Fungal phylum forming basidiocarps.

• Lichen: Symbiotic association of fungus and photosynthetic partner.

• Parazoa: Animals lacking true tissues.

• Radiata: Animals with radial symmetry.

• Lophotrochozoa: Protostome superphylum with lophophore/trochophore.

• Ecdysozoa: Animals that molt exoskeleton.

• Deuterostomia: Animals with deuterostome development.

• Chordate: Animal with notochord, nerve cord, pharyngeal slits, tail.

• Mammal: Animal with hair, mammary glands, endothermy, teeth.

Additional info:

• Expanded explanations of anatomical features and evolutionary relationships were added for completeness.

• Images included are directly relevant to the anatomical identification required for lab and exam preparation.