Parasite Diversity Exam

Parasite

1. Metabolically dependent on anoter living organism (host)

2. They have the potential to cause harm to the host

Ectoparasite

A parasite that lives on the external surface of a host,

e.g., fleas or lice, feeding on its tissues or blood

Endoparasite

A parasite that lives inside the body of a host, such as tapeworms or roundworms, deriving nutrients from the host's internal environment - their blood, muscle, and intestinal tract

Macroparasite

A parasite visible to the naked eye; Ex: tapeworms, nematodes, flukes, which generate a weak immune response

• Their impact is tied to the number of parasites present.

Microparasite

Parasites that are microscopic, reproducing quickly and asexually, and inducing a strong immune response. Ex: influenza (viruse), mycobacterium tuberculosis (bacteria), Giardia (protozoa).

Pathogen

Characterized by causing disease, which is only the case for some parasites.

(ex. anything that causes disease)

Micropredators

They feed on small amounts from multiple hosts

Ex: Leaches

Vectors

They transmit parasites from one host to another, transmitting pathogens

Parasitoid

A parasite whose larvae eats the host while the host is still living

Habitat

living in/on a host provides a stable environment for many places to live

• Once inside the host, there are virtually no predators

Mobility

The act of a parasite dispersing its offspring widely on a host - using host as a personal vehicle

Energy

Parasitism requiring low energy expenditure to obtain abundant resources

What tends to happen to genomes when organisms transition from free-living to parasitic?

Parasites depend on their hosts for resources and no longer need some genes required for independent survival. Those genes are gradually lost, causing genome reduction

Briefly explain why natural selection would favor the transition of a free-living organism to a parasitic organism.

A host may be provided with reliable resources while the energy cost is reduced, thereby increasing survival and reproduction to favor traits in parasitism

Major groups on the tree of life, and particularly those that contain parasites.

Major Groups: Bacteria, Archaea, and Eukarya.

Bacteria- Contains some parasites, while many different eukaryotic lineages contain parasites.

Archaea- Have no known parasites

Eukarya- (Eukaryotic) Many Parasites

Prokaryotes vs. eukaryotes

Major Differences

• All proks are unicelluar, have a cell wall and circular chromosomes (Are 10x smaller)

• Euk have a nucleus and membrane-bound organelles, proks dont

Within eukaryotes, the general differences between protists, plants, fungi, and animals

Protist- Eukaryotes that are NOT plants, animals, or fungi

Plants- Multicellular photosynthetic/autotrophic eukaryotes

Fungi- Heterotrophic eukaryotes that absorb nutrients

Animals- Multicellular heterotrophic eukaryotes that consume food

Metazoans vs. non-metazoans

Metazoans- Technical term for animals that are multicellular, heterotrophic, with specialized tissues

Non-metazoans- Everything else that isn’t an animal (Ex., bacteria, protists, plants, fungi)

Arthropods (I won’t ask you the technical definition of an arthropod, but given an organism, would you be able to tell that it is/is not an arthropod?)

Has:

• exoskeleton

• are invertebrates

• segmented body

• paired, jointed appendages/legs

(ex. millipedes, centipedes, have NOT evolved parasitism)

Acari

• Have only evolved in ticks and mites

• Act as vectors, transmitting parasites from host to host

• Can harm hosts through feeding on them

Insects

• 3 pairs of legs

• head, thorax, abdomenn (3 segments)

• 2 pairs of wings

Crustaceans

Mostly Aquatic, typically hard exoskeleton

• Have reduced appendages used for locomotion

(ex. shrimp, crabs, lobsters)

Nematoda

A small worm-like animal consisting of 1 million species

• 18 transitions to parasitism

Platyhelminthes

A phylum of worms containing parasites with 13 independent shifts

Explain how viruses are related to other organisms (generally speaking; you don’t need to be able to write in detail about all the possible hypotheses for the origins of viruses)

• Viruses are dependent on host cells for reproduction and parasitize other organisms - because viruses need cells, they have evolved after the first cells appeared

Explain why you can argue that viruses are alive, or you can argue that they are not alive

• Viruses are alive when they have genetic material, can reproduce inside host cells, and can evolve.

• Viruses are NOT alive when they CAN’T reproduce independently, CAN’T metabolize, maintain homeostasis, grow, or respond to stimuli, making them not living

Describe the basic structures that are common to all viruses, and what characteristics make all viruses parasites

• All viruses have a DNA/RNA genome surrounded by a protein capsid;

• Viruses are parasites, as they need a host cell's machinery to replicate since they don’t have their own.

Explain the difference between a bacterial species that is only pathogenic, and a bacterial species that is both pathogenic and parasitic

Only Pathogenic bacteria causes diseases in a host but does NOT depend on the host's resources

BOTH Pathogenic and Parasitic bacteria causes diseases in a host and DEPEND on the host for resources and growth

know the important diseases they are associated with, and what organism is their vector (if applicable):

o Yersinia pestis

Caused: Bubonic Plague

Vector: Transmitted by fleas

• Caused Black Death pandemic in Europe

know the important diseases they are associated with, and what organism is their vector (if applicable):

o Mycobacterium tuberculosis

Caused: Tuberculosis

Vector: An aerobic bacteria that spreads thru the air from person to person - attacks the lungs of humans

know the important diseases they are associated with, and what organism is their vector (if applicable):

o Borrelia burgdorferi

Caused: Lyme Disease

Vector: Tick vectored

• This is the Bulls-Eye Rash”

Define what a protist is relative to other eukaryotes

Protists = a diverse group of eukaryotes that are NOT animals, plants, or fungi

Characteristics: photosynthetic, single-celled, and autotrophic

Recognize the following organisms as protist parasites and know the important diseases they are associated with:

o Genus Trypanosoma

Are blood parasites including mammals, birds, amphibians, squamates and fish

• Vectored by insects, through bite or feces

Trypanosoma Cruzi: Chagas disease, vectored by the kissing bug

Trypanosoma brucei: “Sleeping sickness”, vectored by the tste tste fly

Recognize the following organisms as protist parasites and know the important diseases they are associated with:

o Entamoeba histolytica

Infects up to 50 million people worldwide

Tears apart intestinal tissues, causing Amoebic Dysentery

Recognize the following organisms as protist parasites and know the important diseases they are associated with:

o Malaria parasites, and more specifically Plasmodium falciparum

• Malaria parasites are obligate intracellular parasites that invade blood cells and organ tissues

• Plasmodium falciparum is a protist parasite that invades blood cells

• Vector: Diptera, where sexual reproduction and causes Malaria

Define what a fungus is relative to other eukaryotes

Are heterotrophic eukaryotes that absorb nutrients

They are NOT autotrophic or photosynthetic

Can be either unicellular or multicellular

Recognize the following organisms as parasitic fungi and know the hosts that they infect:

o Genus Cordyceps

• Are endoparasites of arthropods

• Important fungi: insect ‘zombie’
  Fungi that cause behavior changes that induce zombie-like behavior in their host

• Forces it to a location for fungal growth → kills the ant → grows out of the ant and releases spores

Recognize the following organisms as parasitic fungi and know the hosts that they infect:

o Chytrid fungus

Cause by Bacrachochytruim Dendrobatidis, infects the skin of frogs

• Impacts frogs’ ability to breathe

• Causes massive amphibian extinction

Explain what it means to be an animal

An animal is a Metazoan

• multicelluar

• heterotrophic

• specialized tissue

Be able to recognize organisms as belonging to the phylum Arthropoda

• Chelicerata: (Sea Spider, Horseshoe Crabs, Harvestmen, Mites, Scorpions, Spiders)

• Hexapoda: (Insect, Springtail)

• Myriapoda: (Pseudocentipedes, Bristile millipedes, Hexameraceratans, Pill millipedes, Scutigeromorphs, Scolopendromorphs)

• Crustacea: (Seed Shrimp, Mystacocaridans, Fish Lice, Barnacles, Calanoids, Cyclopoids, Mantis Shrimps, Crabs, Lobsters, Horseshoe Shrimps, Water Fleas, Remipedes)

Four major arthropod groups?

• Chelicerata

• Hexapoda

• Myriapoda

• Crustacea

The only true parasites that are insects are?

Lice and Fleas

Recognize the human body and crab lice and the human flea as belonging to these groups

Lice (Order Phthiraptera)

Latin Names:

• The human body louse : Pediculus Humanus

• The human pubic (crab) louse : Pthirus Pubis

Recognize important parasitoid insects

Wasps, Bees, Ants , Flies

Be able to generally describe the lifecycle of a parasitoid wasp (what they do to their hosts to ensure the success of their offspring)

• Evolved to vecome parasotiods, ifecting the eggs and larvae of terrestial insects

• The long ovipositors lay eggs in their victims and also many also paralye their hosts

What species are parasitic members of the true bugs

• bed bugs - feed on vertebrate blood

• kissing bugs - act as vectors for trypanosoma cruzi

What group of protists do kissing bugs vector?

Vector: Feed on vertebrate blood at night, are vectors of chagas disease caused by Trypanosoma Cruzi

What are ectoparasites belonging to the arthropod group acari

Mites and Ticks

Recognize chiggers and Sarcoptes scabei as important mites of humans and other mammals

2 known groups of Acari mites

• Chiggers (Trombiculidae) : the larval form of a mite that causes skin irritation when the larvae inject salivary secretions that digest host cells

• Sarcoptes scabei: Comes form mature females mites burrowing under the skin causing rashes, ithing and hairloss

What is the disease associated with Sarcoptes scabei?

Causes sarcoptic mange or scabes

Recognize the black-legged tick (Ixodes scapularis) as an important tick species What disease does it vector?

Is a vestor for Lyme disease

Recognize __________ as parasitic barnacles (and that these are a group of crustaceans), and their behavior as parasitic castrators

• rhizocephalans

behavior: they inhibit growth and reproduction and may induce loss of gonad function (parasitic castration)

• also changes the hosts behavior causing it to protect the parasite egg mass as if it were it’s own

Recognize _______ and _______ as crustaceans

• amphipods

• isopods

What is a parasitic isopod that infects fish

Recognize the tongue-eating louse (Cymothoaexigia)

Recognize the following organisms asimportant nematode parasites of humans

• Trichinella spiralis

• Hookworms

• Guinea worm (Dracunculus medinensis)

• Filarial nematodes

Endoparasites of insects that alter the behavior of their hosts and cause them to enter bodies of water

 

Nematomorpha (hairworms)