Protists and Invertebrate Diversity

These flashcards encapsulate key vocabulary terms and definitions related to the diversity of protists and invertebrates, as explained in the lecture notes.

Mull

A type of soil characterized by intense mixing of organic matter with mineral soil particles due to soil faunal activity. generally, form under deciduous trees with more nutrient-rich litter.

Moder

A soil form with less rapid transformation of litter, primarily by litter-dwelling animals and fungi. intermediate properties of the mull and mor humus forms. Intermediate properties of the mull and mor humus forms.

Mor

A soil type with slow transformation and accumulation of undecayed plant residues, typically found under conifers. Generally present under conifers and is dominated by fungal decomposition leading to a compact-matted structure of fungal hyphae, low pH and an abrupt boundary between organic and mineral horizons.

Protists

A diverse group of microorganisms that include flagellates, amoebae, ciliates, and others that inhabit various moist environments.

Flagellate

A type of protist that uses a whiplike tail to propel itself and typically feeds on bacteria.

Amoebae

Single-celled protists that can engulf prey; can be further categorized into naked and testate forms.

Testate amoebae

Amoebae that possess a shell ('test'), which can be made of silicon or carbon.

Ciliates

Protists that have hair-like structures called cilia for movement and feeding and may form protective encysted forms.

Invertebrate

Animals that lack a backbone, including a wide variety of phyla such as arthropods, mollusks, and annelids.

Ecdysozoa

A major group of animals including arthropods and nematodes, characterized by molting their exoskeleton.

Lophotrochozoa

A clade within the protostomes that includes annelids and mollusks, characterized by a lophophore or trochophore larval stage.

Echinodermata

A group of marine invertebrates with radial symmetry, including starfish and sea urchins.

Placozoa

Simplest known multi-cellular organisms that exhibit a simple flat body structure.

Cnidaria

A phylum of invertebrate animals that includes jellyfish and corals, characterized by stinging cells called cnidocytes.

Annelida

A phylum of segmented worms like earthworms and leeches, known for their closed circulatory systems and multiple hearts.

Chordata

A phylum that includes all animals with a notochord, encompassing vertebrates and some invertebrates.

Hexapoda

A class within the arthropods that includes insects, characterized by having six legs. Most insects are terrestrial, and they were the first to adapt to flight. 2/3 of all flowering plants are pollinated by insects. Hexapoda are characterized by a body divided into three parts: head, thorax, and abdomen, and have antennae and compound eyes.

Mollusca

A diverse phylum of invertebrates that includes snails, clams, and octopuses.

Nematoda

A phylum of roundworms, known for their cylindrical bodies and diverse ecological roles. Have one way- digestive system. Can feed on root hairs, injuring or killing the plant. Change root growth structure. Some break down chitin and cellulose/lignin.

Isopoda

A group of crustaceans commonly found in soil considered cryptozoans—hiding animals. Nocturnal habits. Great at breaking down detritus. Seem to be preferentially coprophagous. Coprophagy allows further breakdown of lignin and cellulosic compounds. Need damp conditions, biggest threat to them is dessication.

Collembola

Also known as springtails, these are tiny wingless insects that can jump using a lever-like furcula. Can reproduce rapidly in times of disturbance. Pheromonal reproductive cues. Parthenogenic reproduction very common, as it is gender plasticity.

Oligochaetes

A class of annelids that includes earthworms, notable for their segmented bodies.

Eumetazoa

A clade of animals that possess specialized tissues and include most of the animal kingdom.

Tartigrades

“slows stepper” tari grado. Bilaterally symmetrical, four pairs of legs that can survive extreme conditions, often referred to as water bears. Particularly associated with mosses, liverworts and lichens.

Oribatid mites

Oldest mite group. Cosmopolitan group (worldwide distribution). Juvenile polymorphism. Reproduce slowly compared to other mites. Brown or colorless, with high amounts of calcium in shells. Most are obligate fungal feeders. Increase soil decomposition through breaking apart hyphae and detritus.

Prostigmatic mites

A diverse group of mites characterized by their specialized mouthparts for piercing and sucking. They reproduce very rapidly when conditions are right. Frequently occur after fire, drought, or other significant disturbance. Regulate nematode populations. Chigger mites are larval forms that as adults eat collembolans.

Megostigmatic mites

Appearing as small tick-like arachnids. Elongate mouthparts suit them well for parasitizing both vertebrates and invertebrates. Including many economically important pests (e.g. varroa mite of bees, fowl mites, rat mites) and even more economically useful biocontrol agents.

Platyhelminthes

More typically, flatworms, flukes, trematodes and turbellarians. Very susceptible to desiccation, so rarely found in soils-even then, only moist, dark places.

Rotifera

Like flatworms, typically aquatic, but can live on land. Sometimes found in moist soils, where they inhabit the thin films of water that are formed around soils particles. Found on mosses and lichens growing on tree trunks and rocks, puddles, in soil or leaf litter, on mushrooms growing near dead trees.

Echytraediae

Known as potworms and live in highly organic terrestrial environments. Genus mesenchytraeus known as “ice worms”, as they live in glaciers and will die if exposed to temperatures a few degrees above freezing. Considered “microdrile oligochaetes”

Oligochaetes

“Megadrile oligochaetes”

Positive effects of earthworms

Promoting beneficial microorganisms. Reducing plant pests. Promoting growth compounds and hormones. Root abrasion and ingestion. Interactions with seeds. Changes in soil structure. Changes in nutrient availability.

Unsavory effects of earthworms

Change in species composition. Alteration of biogeochemical cycles. Mixing of soil strata. Introduction of microbial communities. Removal of litter layer.