BIOL4660_Lecture 6

Copepoda belong to the phylum Arthropoda and subphylum Crustacea.
Major Class: Maxillopoda
Sub-class: Copepoda
Over 10,000 species identified.
Three major free-living orders in freshwater:
- Calanoida: Pelagic, planktonic copepods.
- Cyclopoida: Predatory copepods.
- Harpacticoida: Benthic copepods.

Segmented bodies range from approximately 0.2 to 5 mm in length.
Characterized by a cylindrical body and long first antennae; no carapace.
Unique features:
- Spiny legs for locomotion.
- Single anterior eye.
Developmental stages:
- Nauplius Stage: Initial larval form with three pairs of legs.
- Copepodite: Immature adult form after several molts.
No cyclomorphosis observed.
Coloration:
- Bright colors (e.g., red, orange, blue, green) serve photoprotection but attract visual predators.

Sexual reproduction only, lacking parthenogenesis.
Egg hatching leads to nauplius larvae which subsequently develop into copepodites.
Some species can enter a diapause state as resting eggs during unfavorable conditions, which can survive in sediments for decades.
Population dynamics influenced by longevity and survival rather than egg production.

Feeding behavior:
- Raptorial feeding by seizing food particles with mouth.
Diet changes with maturity:
- Juveniles consume bacteria & algae.
- Adults may shift to omnivorous or predatory diets depending on available resources.
Feeding habits by order:
- Calanoid: Generally omnivorous; modifies diet with environmental factors.
- Cyclopoid: More predatory; lacks filtering mechanisms.
- Harpacticoid: Benthic feeders with mouth parts adapted for scraping.

Found in various aquatic zones:
- Pelagic: Open water.
- Littoral: Shore areas.
- Profundal: Deep water layers.
Key ecological role in food chains of oligotrophic lakes, contributing to biomass through diurnal vertical migrations.

Bivalvia: Two shells connected by a hinge ligament; filter feeders utilizing gills.
Gastropoda: One shell or no shell; possess radula for scraping food.
- Internal gills for respiration in Prosobranchia.
- Pouched gills in Pulmonata, using lungs for breathing.
- Distinct spiraling shapes characterize snails.

Reproduction featuring external fertilization; produces trochophore larvae and either veliger larvae or miniature adults.
Some mollusks display hermaphroditism and internal fertilization but generally maintain a unisexual reproductive system.

Diet primarily herbivorous or omnivorous.
Bivalves filter feed on suspended matter; gastropods graze on submerged algae and periphyton.

Adapted to nearly all freshwater ecosystems, especially well-oxygenated areas like rivers, often found on surfaces like rocks and plants.
Specific niches for different classes, e.g., Bivalves thriving in moderate currents.

Classified under Phylum Chordata, with subclasses (e.g., Osteichthyes - bony fishes).
Teleost fish represent 96% of all species; fish are highly diverse.

Body size and shape vary widely; many exhibit bright colors for mating.
Gills facilitate gas exchange for respiration; some species use filter-feeding methods.

No diapause; dependent on aquatic conditions for life cycles.
Sexual reproduction, with variations in egg producing based on species complexity.

Predaceous feeding patterns; various dietary preferences including herbivory, detritivory, and omnivory.
Morphologies adapted to specific prey capture methods (e.g., suction feeding).

Fish occupy all permanent freshwater environments, inhabiting various zones (pelagic, littoral, benthic) based on their feeding habits.

Structures include roots, stems, and leaves; some large macroalgae function similarly to macrophytes.

Primarily reproduce once a year through vegetative and sexual reproduction, requiring light for growth.

Utilize photosynthesis, some are carnivorous to acquire nutrients (e.g., Pitcher Plant).

Different types exist based on attachment and size:
- Attached: Rooted vegetation (e.g., Sedge, Water soldier).
- Floating: Rooted or not; includes Duckweed and bladderworts.

Important in food webs, nursery habitats, and can act as nuisances (invasive species). Some species are cultivated for food like wild rice and cattails.