Study Guide: Fungi, Animals, and Invertebrates (BIOL 1407)

Fungi

Among the most diverse and widespread organisms.

Ecological role of Fungi

Play a key ecological role: decomposition and nutrient recycling.

Characteristics of Fungi

Eukaryotic, Heterotrophic, Unicellular or multicellular, Filamentous (hyphae).

Hydrolytic enzymes

Fungi secrete hydrolytic enzymes into surroundings.

Nutrient absorption in Fungi

Absorb small organic molecules.

Decomposers (Saprobic)

Absorb nutrients from nonliving material, e.g., fallen logs, dead animals.

Parasites

Absorb nutrients from living hosts, e.g., ringworm, Septobasidium fungi.

Mutualists

Provide and receive nutrients in a symbiotic relationship.

Lichens

Fungi provide structure, moisture retention, protection; Algae/cyanobacteria provide carbon compounds, nitrogen fixation.

Fungal Body Structure

Primarily multicellular with hyphae (filamentous structures).

Chitin

Walls of hyphae are made of chitin.

Septa

May divide cells; allow passage of organelles.

Mycelium

Networks formed by hyphae.

Mycorrhizae

Mutualistic fungi present in almost all vascular plants that enhance nutrient uptake.

Ectomycorrhizal

Hyphae form sheath around root, found in conifers.

Arbuscular Mycorrhizal

Hyphae penetrate cell wall, common in crop plants.

Plasmogamy

Fusion of cytoplasm in fungal sexual reproduction.

Karyogamy

Fusion of nuclei that forms diploid zygote.

Meiosis in Fungi

Creates haploid spores.

Asexual reproduction in Fungi

Spore production via mitosis, includes molds (e.g., Penicillium) and yeasts (budding).

Evolution of Fungi

Evolved from flagellated ancestor.

Opisthokonts

Clade that includes animals, fungi, and some protists.

Nucleariids

Closest relatives of fungi, which are amoebas.

Colonization of land by Fungi

Fungi colonized land before plants (~470 mya).

Chytridiomycota

Oldest group of fungi; aquatic, flagellated spores (zoospores); can be decomposers, parasites, or mutualists.

Zygomycota

Now split into two clades: Zoopagomycetes (mostly parasites) and Mucoromycetes (includes fast-growing molds like Rhizopus).

Glomeromycota

Form arbuscular mycorrhizae with plants; essential for plant nutrient uptake.

Ascomycota

Known as 'Sac Fungi'; produce spores in asci inside fruiting bodies (ascocarps); include molds, yeasts, truffles, morels; 25% form lichens.

Basidiomycota

Known as 'Club Fungi'; produce spores on basidia inside basidiocarps; includes mushrooms, puffballs, shelf fungi; decompose wood (especially lignin).

Kingdom Animalia

Extremely diverse group including planarians, rotifers, grasshoppers, monkeys.

Eukaryotic

Organisms whose cells contain a nucleus and organelles.

Multicellular

Organisms composed of multiple cells.

Heterotrophic

Organisms that cannot make their own food.

Aerobic respiration

Process of producing cellular energy with oxygen.

Sexual reproduction

Reproduction involving the combination of genetic material from two parents.

Motile

Capable of movement at some life stage.

Digestive enzymes

Enzymes used to break down food internally.

Collagen

Most abundant structural protein in animals.

Tissues

Groups of cells that work together to perform a specific function.

Nervous system

System unique to animals responsible for impulse and movement.

Muscular system

System unique to animals that enables movement.

Diploid stage (2n)

Life cycle stage dominated by two sets of chromosomes.

Zygote

Fertilized egg that undergoes cleavage.

Blastula

Hollow ball of cells formed after zygote cleavage.

Gastrula

Layered embryo formed after the blastula stage.

Ectoderm

Germ layer that develops into skin and nervous system.

Endoderm

Germ layer that develops into digestive organs and lungs.

Mesoderm

Germ layer that develops into muscle, bones, and kidneys.

Direct development

Developmental process where young resemble adults.

Indirect development

Developmental process involving a larval stage followed by metamorphosis.

Cell differentiation

Process where cells develop specialized functions.

Gene expression

Determines what type of cell is formed.

Hox genes

Genes that control body plan and segmentation.

Antennapedia

Example of a mutation leading to developmental anomalies.

Oldest animal fossils

Dating back approximately 710 million years.

Choanoflagellates

Closest living relatives to animals, share genes for cell signaling and adhesion.

Neoproterozoic Era

Era marked by first macroscopic animals (Ediacaran biota) and early evidence of predation.

Paleozoic Era

Era characterized by the Cambrian Explosion and rapid diversification of life.

Mesozoic Era

Era known for coral reefs, dinosaurs, and the origin of wings and first mammals.

Cenozoic Era

Era marked by the rise of large mammals and a cooler climate.

Symmetry

Arrangement of body parts; types include radial, bilateral, and asymmetry.

Radial symmetry

Body parts radiate from a central point (e.g., jellyfish).

Bilateral symmetry

Body has mirror-image halves (e.g., humans).

Asymmetry

Body has no symmetry (e.g., sponges).

Diploblastic

2 germ layers (ectoderm, endoderm) - e.g., cnidarians.

Triploblastic

3 germ layers (including mesoderm) - most animals.

Coelomates

Body cavity entirely within mesoderm (e.g., annelids).

Pseudocoelomates

Cavity between mesoderm and endoderm (e.g., roundworms).

Acoelomates

No body cavity (e.g., planarians).

Deuterostome

An organism whose anus develops from the blastopore.

Protostomes

Organisms with spiral, determinate cleavage where the mouth develops from the blastopore.

Deuterostomes

Organisms with radial, indeterminate cleavage where the anus develops from the blastopore.

Invertebrates

Animals without a backbone, making up ~95% of all known animals.

Choanoflagellates

Considered the closest protist relatives of animals.

Phylum: Porifera

Includes sponges, which are mostly marine, lack true tissues, and are filter feeders.

Choanocytes

Collar cells in sponges that capture food.

Amoebocytes

Totipotent cells in sponges that digest food and build spicules.

Zygotes

In sponges, they disperse via water current.

Water Flow in Sponges

In through pores → spongocoel → out osculum.

Medical Importance of Sponges

Source of antibiotics like cribrostatin.

Phylum: Cnidaria

Includes aquatic organisms with radial symmetry that are predators.

Polyp

A sessile body plan in Cnidaria.

Medusa

A motile body plan in Cnidaria.

Cnidocytes

Stinging cells found in Cnidarians.

Nematocysts

Harpoon-like organelles in Cnidarians.

Nerve Net

A system in Cnidarians that coordinates movement without a brain.

Digestive System in Cnidarians

Incomplete, having only one opening.

Medusozoans

Cnidarian clade that alternates between polyp and medusa stages.

Anthozoans

Cnidarian clade that exists only as polyps and forms coral reefs via calcium carbonate skeletons.

Superphylum: Lophotrochozoans

Characterized by bilateral symmetry and various body cavities.

Phylum: Platyhelminthes

Includes flatworms, which are triploblastic but acoelomates.

Gas Exchange in Flatworms

Occurs via diffusion; they have no circulatory system.

Excretory System in Flatworms

Protonephridia with flame bulbs.

Planarians

Free-living flatworms that are freshwater and have eyespots.

Tapeworms

Parasitic flatworms that live in the digestive tracts of vertebrates and have no digestive system.

Scolex

The hooks and suckers of tapeworms.

Proglottids

Reproductive sacs in tapeworms.

Rotifers

Freshwater organisms with cilia that draw water into the mouth and have an alimentary canal.

Phylum: Mollusca

Includes marine, freshwater, and terrestrial organisms with a body plan consisting of a muscular foot, visceral mass, mantle, and radula.

Bivalves

Includes clams, oysters, mussels, and scallops, which are filter feeders and lack a radula.