Lecture Notes Flashcards

Phylum Nematoda (Roundworms)

• Abundance and Habitat:

  • One of the most abundant animal phyla after arthropods.

  • Found everywhere, even in Antarctica.

  • Some are parasitic, others are not.

• General Characteristics:

  • Unsegmented.

  • Triploblastic.

  • Protostome development.

  • False coelom (pseudocoelom).

  • Complete digestive tract.

• Cuticle:

  • Functions in gas exchange and nutrient absorption.

  • Protects from enzymes and toxins.

• Size and Examples:

  • Most are less than 1 cm, but some are larger.

  • Example: Ascaris (causes ascariasis).

• Growth and Molting:

  • Grow by shedding their cuticles (molting).

  • Molt about four times in their lifetime.

• Muscles and Movement:

  • Lack circular muscles.

  • Only have longitudinal muscles.

  • Move in a thrashing motion (side to side movement).

• Reproduction:

  • Mostly reproduce sexually.

  • Males typically smaller than females (except in mammals).

• Cryptobiosis:

  • Able to suspend metabolic activity (dormancy).

  • Cryptobiosis: Almost no metabolic processes occurring; unlike hibernation, where metabolism is slowed down but still present.

• Importance and Diseases:

  • Involved in decomposition.

  • Cause diseases (ascariasis, pinworm, guinea worm, trichinosis, elephantiasis/lymphatic filariasis).

• Nematode Diseases in The US:

  • Common in areas with poor sanitation.

  • Rising in the South US due to poverty and lack of proper sewage disposal.

• Ascariasis:

  • Caused by Ascaris.

  • Infection through contaminated water or food.

  • Eggs are microscopic.

  • Treatment: Surgery or deworming drugs (though deworming drugs have risks; ascarias can go upward, they can actually go out of your intestine and go upward as you can see in this picture on the left here. It's coming out of this poor kid's mouth and nose, which is oof).

• Pinworm:

  • Small (less than 1 mm).

  • Lives in the large intestine.

  • Female lays eggs near the anus, causing itching.

  • Eggs transferred by scratching and touching mouth or others' mouths.

  • Common in children.

• Guinea Worm:

  • Larvae live in copepods (water fleas).

  • Infection through drinking water containing copepods.

  • Larvae survive stomach acid, mature, and mate.

  • Female burrows through skin to lay eggs, causing burning sensation, and host puts feet in water and repeats the process.

  • Removal: Rolling worm on a stick.

  • Breaking the worm can cause anaphylactic reaction and secondary bacterial infections.

  • Possible origin of the medical symbol (rod with serpent).

• Trichinosis:

  • Caused by Trichinella (nematode larvae).

  • Spread through undercooked pork (or other animals).

  • Larvae burrow out of tissue and migrate through the body.

  • Tropism for the head: Worms tend to migrate towards the head.

  • Damage to vital organs (heart, brain) can be fatal.

  • Prevention: Cook meat thoroughly.

• Lymphatic Filariasis (Elephantiasis):

  • Spread by mosquitoes carrying larvae.

  • Infected with multiple larvae.

  • Male and female mate, male dies, female lives in lymphatic ducts (lower legs).

• Lymphatic blockage:

  Fluid 
  

  rightarrow Stagnant

• Accumulation
  rightarrow Swelling of the lower legs (edema).

  Tissue swelling leads to skin roughness, nerve damage, and increased risk of infection.
  

  • Scrotal edema in males (unhealthy size).

  • Treatment: Early treatment can prevent progression. Damage to tissue can't be reversed such as elephantiasis. Debridement (tissue removal) is risky due to blood vessel entanglement.

Phylum Arthropoda

• Abundance:

  • Largest animal group.

  • Three out of every four animals.

  • Found everywhere on Earth.

• Simotowa axigua:

  • Arthropod that enters fish mouth, bites the tongue, and lives there.

• General Characteristics:

  • Coelomate.

  • Segmented bodies.

  • Exoskeleton (chitin).

  • Jointed appendages.

  • Protostome development.

  • Triploblastic.

• Evolution of Segmentation:

  • Early arthropods (e.g., trilobites) had less distinct body regions.

  • Evolved to have specialized body parts for different functions.

• Molting (Ecdysis):

  • Arthropods shed their exoskeleton to grow (ecdysis).

• Circulatory System:

  • Open circulatory system.

\Rightarrow Hemolymph: fluid mixes with body tissue.

    Closed 

Rightarrow Keeps fluid inside the circulatory system known as blood.

• Subphyla of Arthropoda:

  • Chelicerates

  • Myriapods

  • Hexapods

  • Crustaceans

  • Trilobitomorpha (extinct)

Subphylum Chelicerata

• Key Feature:

  • Possess chelicerae (appendages).

• Appendages:

  • Chelicerae: First appendages used for food handling.

  • Pedipalps: Next appendages, also for food handling.

  • Other appendages for walking, swimming, etc.

• Horseshoe Crab:

  • Ancient animal.

  • Blue blood (metal in blood is not iron).

  • Blood used to detect microbes in drugs (valuable).

  • Found along the Pacific Ocean in the tropics (Thailand, Australia, and East Coast of the United States).

• Class Arachnida:

  • Includes spiders, scorpions, ticks, mites, etc.

  • Body divided into cephalothorax and abdomen.

  • Four pairs of walking legs (8 legs).

Subphylum Myriapoda (Uniramia)

• Classes:

  • Diplopoda (millipedes)

  • Chilopoda (centipedes)

• Millipedes:

  • Two pairs of legs per segment.

  • Round body.

• Centipedes:

  • One pair of legs per segment.

  • Flattened body.

  • Centipedes are more venomous predators than millipedes. Because centipedes, not predators themselves, need venom.

Subphylum Hexapoda (Insects)

• Abundance:

  • Most abundant arthropod group.

• General Characteristics:

  • Three body areas: head, thorax, abdomen.

  • One pair of antennae.

  • Six legs (three pairs).

  • One or two pairs of wings.

• Metamorphosis:

  • Changes in body shape.

    Complete
    Rightarrow Holometabolous : larvae look very different from adults (e.g., caterpillar to butterfly). Larvae: Maggots

    Incomplete
    Rightarrow Hemimetabolous : young look like miniature adults (e.g., grasshoppers, crickets).

• Importance of Insects:

  • Decomposers.

  • Pollinators (important for fruit production).

  • Vectors of disease.

  • Control other insects (lady beetles eat aphids).

• Insect Population And Human:

  • Population of 8,000,000,000 people

  • With increase damages, climate change, there is the idea of eating insects for protein (farm raised insects are healthy, they contain protein, and do not have as bad fat as cows or pigs, however culturally change the thinking for more acceptance).

• Dung Beetles:

  • Recycle nutrients by collecting and breaking down animal waste (dung).

  • Astronomers: Use the stars/moon to navigate.

  • Some lay eggs inside dung.

• Pollinators:

  • Bees are the most common pollinators.

  • Flies, butterflies, moths, and beetles also contribute to pollination.

Subphylum Crustacea

• Habitat:

  • Mostly aquatic animals (ocean and freshwater).

• Appendages:

  • Biramous: Forked appendages.

• Body Organization:

  • Head, thorax, and abdomen (sometimes head and thorax are fused).

• Antennae:

  • Two pairs of antennae.

• Food Handling Appendages:

  • Mandibles, maxillae, maxilliped (three pairs).

• Other Appendages:

  • Walking legs.

  • Swimmerets (for swimming).

• Carapace:

  • Shell covering the cephalothorax made of chitin.

• Class Malacostraca (Decapoda: means 10 legs):

  • Five pairs of appendages.

  • Examples: Lobster, crab, crayfish, shrimp, krill, woodlice (sowbugs, roly poly).

• Mantis Shrimp

  High speed punch. The speed is so fast the the temperature becomes equivalent to the sun! Breaks aquarium.
  

• Pistol Shrimp: Creates high speed pressure which stuns whatever it wants to eat.

• Krill and Omega-3s:

  Omega-3s has NOT been validated, and the fishes eat the krills to get oil. We are taking Krill/Food out of the oceans for marine animals.
  

Class Maxillopoda

• Characteristics:

  • Unusual looking crustaceans (not shrimp).

• Examples:

  • Copepods (water fleas).

  • Barnacles.

  • *Copepods are important for food chains.

• Barnacles:

  • Produce shells and grow on ships and other surfaces.

  • Body inside shell, use cirri (feet) to draw water towards their mouth for feeding.

  • Harm shipping industry (increase weight and drag).

  • Removed using toxic chemicals (creosote and hot water).

    Challenge

    Invent solution to remove them without harming the environment.

• Barnacle Reproduction:

  • Hermaphrodites.

  • Do not self-fertilize, have the longest penis in the animal kingdom (to reach other barnacles).