Fungi and Animals

Lab exam 2

Fungi

Eukaryotic heterotrophs that absorb nutrients from their environment, often through secreted enzymes.

Absorption

Nutritional mode where fungi secrete enzymes to break down large molecules outside their body, then absorb the smaller components.

Hydrolytic Enzymes

Enzymes secreted by fungi to break down complex organic molecules (proteins, fats, sugars) into simpler ones for absorption.

Chitin

A strong, flexible polysaccharide found in fungal cell walls that supports absorption and structure.

Symbiosis

A close, long-term interaction between two different organisms.

Mycorrhiza

A mutualistic association between fungal hyphae and plant roots; fungi receive glucose, plants gain increased water/nutrient absorption.

Yeast

Unicellular fungi; Saccharomyces cerevisiae is a classic example (baker's/brewer's yeast).

Hyphae

Slender filaments that make up the body of multicellular fungi.

Mycelium

A branching network of hyphae; increases surface area for nutrient absorption and anchors fungi to substrates.

Spore

A reproductive cell capable of developing into a new organism; may be sexual or asexual.

Sexual Reproduction (Fungi)

Typically includes plasmogamy → heterokaryotic stage → karyogamy → meiosis → spore production.

Plasmogamy

Fusion of the cytoplasm of two parent mycelia.

Heterokaryotic Stage

A stage where cells contain two or more genetically different haploid nuclei.

Karyogamy

Fusion of haploid nuclei to form a diploid nucleus ('zygote').

Haplontic Life Cycle

Life cycle in which the haploid stage is dominant, and the diploid stage is brief.

Fragmentation

Mycelium breaks apart, and each fragment can grow into a new fungus.

Budding

A form of asexual reproduction in yeasts where a new cell forms from the parent cell after mitosis.

Conidia

Asexual spores that are genetically identical to the parent and produced at the tips of hyphae.

Chytridiomycota (Chytrids)

Aquatic fungi with flagellated spores (zoospores). Some are decomposers, others are parasites.

Zoospores

Motile (swimming), flagellated spores—unique to chytrids.

Batrachochytrium dendrobatidis (Bd)

A chytrid fungus causing deadly infection in amphibians.

Allomyces

A chytrid decomposer found in wet soils; uses sirenin pheromone to attract male gametes.

Sirenin

A sexual pheromone released by female Allomyces gametes to attract males.

Zygomycota (Zygomycetes)

Fungi including molds like Rhizopus, with a characteristic multinucleate 'zygote' structure.

Rhizopus stolonifer

Common black bread mold; feeds on baked goods.

Zygote Fungi

Refers to zygomycetes' multinucleate diploid reproductive structure (not a true single-nucleus zygote).

Pilobolus

Zygomycete that shoots spores via phototropism to be ingested by grazing animals.

Phototrophic / Phototropism

Movement or growth toward light; used by Pilobolus for spore dispersal.

Ascomycota (Ascomycetes)

Largest fungal group (~65,000 species). Includes yeasts and many plant pathogens.

Ascus

The saclike structure where sexual spores are produced.

Ascocarp

The fruiting body that contains asci.

Apothecium

Bowl-shaped ascocarp.

Cleistothecium

Spherical, closed ascocarp.

Perithecium

Flask-shaped ascocarp.

Ascospores

Sexual spores produced inside an ascus (usually eight per ascus after meiosis and mitosis).

Peziza

An ascomycete with a distinctive apothecium.

Morchella (Morel)

Edible ascomycete that has many apothecia on its fruiting body.

Dutch Elm Disease

Caused by ascomycete fungi; affects elm trees.

Chestnut Blight

Another ascomycete-caused plant disease.

Phylum Porifera

Monophyletic group of organisms descended from a single common ancestor.

Basal Animals

Animals that branched off early in evolutionary history; simplest animals.

True Tissues

Specialized, integrated cell layers (sponges lack these).

Sessile

Stationary; permanently attached to a substrate.

Filter Feeders

Organisms that draw water through their bodies to extract food particles.

Gemmules

Dormant, resistant structures in freshwater sponges (e.g., Spongilla) that survive harsh conditions and germinate into new sponges.

Spicules

Structural elements that support sponges; made of calcium carbonate or silica depending on species.

Spongin

Flexible, collagen-based protein fibers found in commercial bath sponges.

Calcareous Sponges

Sponges with calcium carbonate spicules (examples: Grantia, Leucosolenia).

Hexactinellida (Glass Sponges)

Sponges with silica spicules; typically deep-sea species like Euplectella (Venus' Flower Basket).

Substrate

Surface or material an organism lives on or is attached to.

Phylum Cnidaria

Includes organisms with specialized stinging cells for defense and capturing prey.

Cnidocytes

Specialized stinging cells used for defense and capturing prey.

Nematocyst

The stinging capsule inside a cnidocyte.

Diploblastic

Having two germ layers: ectoderm and endoderm.

Radial Symmetry

Body plan arranged around a central axis.

Gastrovascular Cavity

Central digestive compartment with a single opening (mouth/anus).

Polyp

Sessile, cylindrical body form with tentacles upward.

Medusa

Free-swimming, umbrella-shaped form.

Dimorphic

Existing in two body forms (polyp + medusa).

Medusozoa

Clade including cnidarians with a medusa stage.

Scyphozoa (True Jellyfish)

Common genus of scyphozoan jellyfish.

Planula

Free-swimming, ciliated larval stage of cnidarians.

Scyphistoma

Polyp stage of a scyphozoan.

Ephyra

Immature medusa stage that develops from the polyp.

Hydrozoa

Includes colonial hydrozoans with both polyp and medusa stages.

Physalia (Portuguese Man-O-War)

Colonial hydrozoan that resembles a jellyfish; has specialized polyps.

Colonial

Composed of many connected, specialized individuals (polyps) functioning as a unit.

Phylum Ctenophora (Comb Jellies)

Marine organisms known as comb jellies; superficially resemble cnidarians but differ in key ways.

Ctenophore

Marine organisms known as comb jellies.

Bioluminescence

Ability to produce and emit light.

Ctenes

Eight rows of fused cilia used for swimming (characteristic of ctenophores).

Colloblasts

Sticky, adhesive cells on tentacles used to capture prey (NOT stinging cells).

Retractable Tentacles

Tentacles that can be drawn in; used for capturing prey.

Complete Digestive System

Digestive system with two openings (mouth + anus); unlike cnidarians' incomplete system.

Phylum Platyhelminthes

Flatworms

Acoelomate

Animals lacking a body cavity.

Gastrovascular Cavity

A digestive chamber with one opening (mouth = anus); incomplete digestive system.

Osmoregulation

Maintaining water balance in the body.

Protonephridia

Excretory/osmoregulatory structures made of 'flame cells.'

Flame Cells

Specialized cells in protonephridia that regulate water movement.

Catenulida

Small clade (~100 species); mostly freshwater chain worms.

Rhabditophora

Largest flatworm clade (~20,000 species); includes free-living forms, parasitic flukes, and tapeworms.

Planarians

Free-living freshwater flatworms; well-known in labs.

Dugesia tigrina

Common brown planarian; used in regeneration studies.

Ocelli

Light-sensitive eye spots.

Auricles

Lateral flaps used for chemical detection (olfactory sensing).

Cephalization

Concentration of sensory structures at the anterior (head) end.

Undulatory Movement

Wave-like muscular movement for locomotion.

Diffusion (Waste Removal)

Process of eliminating nitrogenous waste through body surface.

Digenetic

Requiring two or more hosts to complete life cycle.

Trematodes

Parasitic flukes; no free-living stages.

Primary Host

The vertebrate host where sexual reproduction occurs.

Intermediate Host

Typically a snail; site of asexual reproduction.

Clonorchis sinensis

Human liver fluke.

Fasciola hepatica

Sheep liver fluke.

Cestodes

Tapeworms; strictly parasitic; lack digestive system.

Scolex

Attachment organ at anterior end of tapeworm; has suckers and hooks.

Proglottids

Reproductive body segments of tapeworms.

Gravid Proglottid

Mature segment filled with thousands of fertilized eggs.

Taenia pisiformis

Tapeworm parasite of carnivores.