Animal-Like Protists Lab

Animal-Like Protists (Lab 4)

• Key groups include Euglenozoa, Kinetoplastids, Apicomplexa, Ciliophora, and Unikonta.

• Protists are characterized as unicellular, eukaryotic organisms that are mostly aquatic.

• Protists nutrition include diverse modes, such as autotrophic and heterotrophic.

Modes of Locomotion

• Flagella: used by Euglena

• Cilia: used by Paramecium and Vorticella

• Pseudopodia: used by Amoeba

• Euglena possess a flagellum (whiplash type) and a red eyespot (stigma) for detecting light

• Trypanosoma are parasitic, lack chloroplasts and absorb nutrients from a host's blood

• Plasmodium lacks locomotion organelles, infects red blood cells, and causes malaria

• Paramecium use cilia for movement and feeding and have an oral groove, contractile vacuole, micronucleus, and macronucleus

• Vorticella are sessile and use cilia around the peristome for generating feeding currents.

• Amoeba move using pseudopodia and lack a rigid cell wall.

Eyespot Function in Euglena

• Detects light, enabling movement towards light sources for photosynthesis (positive phototaxis).

Protist Locomotion Methods

• Flagella: Whip-like tail for movement. (e.g., Euglena)
• Cilia: Short, hair-like structures beating in unison. (e.g., Paramecium)
• Pseudopodia: Extensions of cytoplasm for crawling. (e.g., Amoeba)

Plasmodium Infection

• Transmitted by the bite of an infected female Anopheles mosquito.
• Enters the bloodstream and infects red blood cells.

Euglena Features

• Plant-like: Contains chloroplasts for photosynthesis.
• Animal-like: Moves using a flagellum and feeds heterotrophically without light.

Microscope Identification

• Identify Euglena (flagellum, eyespot)
• Find Trypanosoma among blood cells
• Find Plasmodium inside red blood cells
• Recognize Paramecium structures (oral groove, macronucleus)
• Find Amoeba pseudopodia
• Find Vorticella stalk and cilia

Flatworms (Platyhelminthes) - Lab 7

• Classes include Turbellaria, Trematoda, and Cestoda.

• Flatworms Body plan: Acoelomate, triploblastic, with bilateral symmetry.

• Planaria (Turbellaria): Free-living with eyespots (light detection) and auricles (chemoreception)

• Flukes (Trematoda): Parasitic with oral/ventral suckers and an extensive reproductive system.

• Tapeworms (Cestoda): Parasitic without a mouth or digestive system; the body is made of proglottids.

• Flame Cells: Excretory structures for osmoregulation.

Planaria's Pharynx

• Centrally located to allow feeding while remaining flat.
• Enables feeding from any direction and supports the body plan.

Monoecious and Acoelomate

• Monoecious: Organism with both male and female reproductive organs (hermaphroditic).
• Acoelomate: Lacks a body cavity; internal organs are embedded in solid tissue (e.g., flatworms).

Fluke Protection

• Tough outer tegument (cuticle) resists digestive enzymes.
• Protects from the host's immune system.

Tapeworm Digestion

• Tapeworms absorb pre-digested nutrients directly from the host's intestines through their body surface
• This makes a digestive system unnecessary.

Microscope Identification

• Identify Planaria w.m. and c.s. (auricles, pharynx, eyespots)
• Find Fasciola / Clonorchis (oral sucker, ventral sucker)
• Find Taenia proglottids (scolex, hooks, suckers, reproductive organs)

Molluscs (Lab 8)

• Classes include Gastropoda (Snails), Bivalvia (Clams), and Cephalopoda (Squid).

Mollusk Characteristics

• Soft body, muscular foot, mantle, radula (except bivalves) with bilateral symmetry.
• Adaptive Radiation: Variety of body forms adapted to different environments.
• Snail Locomotion: Uses a muscular foot and secretes mucus.
• Bivalves: Filter feeders, sedentary, with an open circulatory system.
• Cephalopods: Active predators with a closed circulatory system and highly developed eyes.

Mollusk Features

• Muscular foot
• Visceral mass
• Mantle
• Radula (except in bivalves)

Foot Structure Comparison

• Snail (Gastropod): Broad, muscular foot for crawling.
• Clam (Bivalve): Wedge-shaped foot for digging/burrowing.
• Squid (Cephalopod): Modified foot forms tentacles and arms for grasping prey and movement.

Cephalopod Sensory Systems

• Cephalopods, being active predators, use rely on advanced eyes, large brains, and sensory tentacles.
• These help them locate prey and avoid predators.

Clam Adductor Muscles

• Hold clam shells tightly closed
• Provide protection from predators and prevent desiccation.

Specimen Identification

• Identify external and internal features of a snail (tentacles, eyes, foot)
• Locate Clam's adductor muscle, gills, visceral mass, and heart.
• Identify Squid's tentacles, siphon, mantle, ink sac, and gills.

Comprehensive Questions

• Match organisms to phylum/class
• Identify structures with a microscope or specimen tray
• Compare Planaria vs. Tapeworms
• Compare Euglena vs. Paramecium
• Compare Bivalves vs Cephalopods
• Explanation of how Paramecium feeds
• Explanation of the life cycle of Plasmodium or Fasciola
• Describe how flatworms excrete waste
• Describe how planaria can learn
• Discuss adaptive radiation in mollusks
• Explain the importance of the protist group related to sponge ancestors

Practical Exam Tips

• Master microscope focusing techniques
• Familiarize yourself with slides and preserved specimens
• Practice labeling diagrams of protists, flatworms, and mollusks
• Understand the functions of each structure, not just names