Fungi and Animal Diversity: Study Guide for Chapters 31–33

Chapter 31: Fungi

Fungal Vocabulary and Basic Concepts

Fungi are a diverse kingdom of eukaryotic organisms with unique life cycles and ecological roles. Understanding their terminology and reproduction is essential for studying their biology.

• Hyphae: Thread-like filaments that make up the body (mycelium) of a fungus.

• Mycelium: The mass of hyphae forming the vegetative part of a fungus.

• Chitin: A strong, flexible polysaccharide in fungal cell walls.

• Plasmogamy: Fusion of the cytoplasm from two parent mycelia.

• Karyogamy: Fusion of nuclei from the fused cells, resulting in a diploid zygote.

• Fertilization vs. Karyogamy: In fungi, fertilization is a two-step process: plasmogamy (cytoplasm fusion) followed by karyogamy (nuclear fusion). In animals, fertilization typically refers to the fusion of gametes (egg and sperm) in a single step.

Fungal Reproduction

• Asexual Reproduction: Most fungi reproduce asexually by producing spores through mitosis (e.g., molds).

• Sexual Reproduction: Involves plasmogamy, heterokaryotic stage (cells with two or more nuclei), karyogamy, and meiosis to produce genetically diverse spores.

• Key Terms: Spores, conidia (asexual spores), fruiting bodies (e.g., mushrooms).

Fungal Phyla

Fungi are classified into several phyla, each with unique features and ecological roles.

• Chytridiomycota (Chytrids): Aquatic fungi with flagellated spores; some cause amphibian diseases.

• Zygomycota (Zygomycetes): Includes bread molds (Rhizopus); forms resistant zygosporangia.

• Glomeromycota: Form arbuscular mycorrhizae with plant roots, aiding nutrient exchange.

• Ascomycota (Ascomycetes): "Sac fungi"; produce spores in sac-like asci. Examples: morels, truffles, yeasts, Penicillium.

• Basidiomycota (Basidiomycetes): "Club fungi"; produce spores on basidia. Examples: mushrooms, puffballs, shelf fungi. Ecological importance: decomposers, some form mycorrhizae.

Lichens

Lichens are symbiotic associations between a fungus (usually an ascomycete) and a photosynthetic partner (alga or cyanobacterium). They are not a fungal phylum but are important for their role in colonizing harsh environments and as bioindicators.

Chapter 32: Introduction to Animal Diversity

Characteristics of Animals

Animals are multicellular, heterotrophic eukaryotes with tissues that develop from embryonic layers.

• Key Features: Multicellularity, lack of cell walls, nervous and muscle tissue, sexual reproduction, development from a blastula.

Animal Body Plans

Animal body plans are defined by four main features:

• Symmetry: Radial (e.g., jellyfish) or bilateral (e.g., humans).

• Tissues: True tissues (except sponges), organized into germ layers.

• Body Cavities: Coelomate, pseudocoelomate, or acoelomate.

• Developmental Patterns: Protostome vs. deuterostome development.

Early Development and Vocabulary

• Cleavage: Rapid cell division after fertilization.

• Bastula: Hollow ball of cells formed during early development.

• Gastrulation: Formation of germ layers (ectoderm, mesoderm, endoderm).

Protostomes vs. Deuterostomes

Feature	Protostomes	Deuterostomes
Cleavage	Spiral, determinate	Radial, indeterminate
Coelom Formation	Schizocoelous (splitting)	Enterocoelous (outpocketing)
Blastopore Fate	Mouth develops first	Anus develops first

Germ Layers

• Ectoderm: Outer layer; forms skin and nervous system.

• Endoderm: Inner layer; forms digestive tract.

• Mesoderm: Middle layer; forms muscles, organs (in triploblastic animals).

• Diploblastic: Two germ layers (e.g., cnidarians).

• Triploblastic: Three germ layers (e.g., all bilaterians).

Body Cavities

Type	Description	Example
Coelomate	True body cavity lined by mesoderm	Earthworm
Pseudocoelomate	Body cavity partially lined by mesoderm	Roundworm
Acoelomate	No body cavity	Flatworm

Body Symmetry

• Radial Symmetry: Body arranged around a central axis (e.g., sea anemones).

• Bilateral Symmetry: Body has left and right sides (e.g., humans, insects).

• Implications: Bilateral symmetry is associated with cephalization (development of a head region).

Chapter 33: Invertebrates

Choanoflagellates

Choanoflagellates are unicellular or colonial protists considered the closest living relatives of animals. Their collar cells resemble sponge choanocytes, supporting the evolutionary link to animals.

Porifera (Sponges)

• Most Basal Animal: Lack true tissues and organs.

• Key Features: Asymmetrical, filter feeders, possess choanocytes (collar cells), spicules for support.

• Diagram Terms: Osculum, spongocoel, choanocyte, amoebocyte, spicule.

Cnidaria

• Eumetazoans vs. Metazoans: Eumetazoans have true tissues; metazoans include all animals.

• Unique Features: Diploblastic, radial symmetry, possess cnidocytes (stinging cells).

• Body Forms: Polyp (sessile) and medusa (motile).

• Feeding: Use tentacles with nematocysts to capture prey.

• Major Groups: Hydrozoa (hydras), Scyphozoa (jellyfish), Cubozoa (box jellies), Anthozoa (corals, sea anemones).

Lophotrochozoans

• Flatworms (Platyhelminthes): Bilateral symmetry, acoelomate, simple nervous system. Four classes: Turbellaria (planarians), Trematoda (flukes), Cestoda (tapeworms), Monogenea.

• Parasitic Life Cycles: Many have complex life cycles involving multiple hosts (e.g., Schistosoma).

• Annelids: Segmented worms. Clades: Polychaeta (marine worms), Oligochaeta (earthworms), Hirudinea (leeches). Leeches produce hirudin, an anticoagulant.

• Mollusca: Body plan includes muscular foot, visceral mass, mantle. Classes: Gastropoda (snails), Bivalvia (clams), Cephalopoda (octopus). Table 33.3 (see below).

Class	Key Features	Examples
Gastropoda	Single, spiraled shell; distinct head	Snails, slugs
Bivalvia	Two-part shell, filter feeders	Clams, oysters
Cephalopoda	Well-developed head, tentacles, closed circulatory system	Octopus, squid

• Lophophores: Ciliated feeding structures in some lophotrochozoans.

• Trochophores: Distinct larval stage in some groups.

Ecdysozoa

• Emergent Properties: Molting (ecdysis) of exoskeleton during growth.

• Nematodes: Unsegmented, pseudocoelomate, complete digestive tract. Important species: Caenorhabditis elegans (model organism), parasitic roundworms (e.g., Ascaris).

• Arthropods: Segmented body, jointed appendages, exoskeleton made of chitin. Subphyla: Chelicerata (spiders), Myriapoda (centipedes), Crustacea (crabs), Hexapoda (insects).

Subphylum	Key Features	Examples
Chelicerata	Fangs or pincers, two body segments	Spiders, scorpions
Myriapoda	Many body segments, many legs	Centipedes, millipedes
Crustacea	Two pairs of antennae, aquatic	Crabs, lobsters
Hexapoda	Three body segments, six legs	Insects

• Insects: Body plan: head, thorax, abdomen. Adaptations: flight, metamorphosis (complete vs. incomplete).

• Metamorphosis: Complete (egg, larva, pupa, adult; e.g., butterflies) vs. incomplete (egg, nymph, adult; e.g., grasshoppers).

• Orders: Lepidoptera (butterflies), Coleoptera (beetles), Diptera (flies), Hymenoptera (bees, ants).

• Ecological Impacts: Pollination, decomposition, disease vectors.

Echinoderms

• Key Features: Marine, radial symmetry (as adults), water vascular system, tube feet.

• Six Classes: Asteroidea (sea stars), Ophiuroidea (brittle stars), Echinoidea (sea urchins), Crinoidea (feather stars), Holothuroidea (sea cucumbers), Concentricycloidea (sea daisies).

• Identification: Recognize by body form and features (e.g., sea stars have arms radiating from a central disk).

Additional info: Where tables from slides were referenced but not provided, logical content was inferred based on standard biology textbooks. Students should refer to their class slides for images and further examples.