Practical 1

Question 1

Kingdom Protista Phylum Euglenozoa

Answer 1

• unicellular
• motile using flagella
• reproduce asexually using binary fission
• some heterotrophic; others autotrophic
• some parasitic
• Genus Euglena
  ~ unicellular flagellates
  ~ heterotrophic and autotrophic
• Genus Trypanosoma
  ~ unicellular flagellate
  ~ human parasite (African sleeping sickness and Chagas Disease)

Question 2

Kingdom Protista Phylum Dinoflagellata

Answer 2

• photosynthetic/autotrophs
• most are free-living, but some are endosymbionts
• 1+ flagella out of the grooves in cellulose plates
• Genus Noctiluca
  ~ free-living
  ~ marine-dwelling
• example: red tide

Question 3

Kingdom Protista Phylum Chlorophyta

Answer 3

• spherical, colonial (groups of unicellular individuals)
• reproduces sexually and asexually
• cells in colony work together for locomotion
• like dinoflagellates, these can cause large algal blooms
• Genus Volvox
  ~ a green algae

Question 4

Kingdom Protista Phylum Apicomplexa

Answer 4

• unicellular
• parasitic
• nonmotile (lack flagella)
• absorb nutrients from their host/environment (osmotrophic)
• subclass Coccidia
  ~ unicellular
  ~ intestinal parasites of vertebrates
  ~ Genus Plasmodium
  - causes malaria

Question 5

Kingdom Protista Phylum Ciliophora

Answer 5

• ciliates (possess cilia)
  ~ cilia is used for locomotion and feeding (heterotrophic)
• most are complex, solitary, unicellular, freshwater
• undergo conjugation (sexual reproduction)
• contractile vacuole: organelle that maintains osmotic balance
• Genus Paramecium

Question 6

Kingdom Protista Phylum Amoebazoa

Answer 6

• part of Supergroup Unikonta (contains animals and fungi)
• unicellular
• extend their cytoplasm to form pseudopodia (“fake feet” for feeding and locomotion)
• many free-living, some parasites
• heterotrophs that consume food via phagocytosis (“cell eating”)
• Genus Amoeba

Question 7

Kingdom Animalia Phylum Porifera (“Pore-bearing”) Distinguishing Characteristics

Answer 7

• body organization: multicellular
• symmetry: asymmetrical
• habitat: aquatic, mostly marine
• adults sessile (cannot move)
• absorb nutrients from water column (filter feeders)
• reproduce:
  ~ asexually: budding or gemmules
  ~ sexually: spawning of gametes into the water column

Question 8

Phylum Porifera Anatomy

Answer 8

• choanocyte: flagellated cells that move water through the sponge
• spicules: hardened structures that serve as an internal skeleton (made of either calcium carbonate or silicon)
• ostia: small pores where water first enters the sponge
• spongocoel: large central canal (absent in leucon body type)
• osculum: larger hole where water exits the sponge

Question 9

Phylum Porifera Class Calcarea

Answer 9

• spicules made of calcium carbonate
• Genus Sycon
  ~ genus of small sponges (up to 7.5 cm)
  ~ syconoid body plane

Question 10

Phylum Porifera Class Hexactinellida

Answer 10

• glass sponges
• spicules made of silicone
• some biologists believe that these are the longest- lived animals on earth
  ~ estimated maximum age of 15,000 years

Question 11

Kingdom Animalia Phylum Cnidaria Distinguishing Characteristics

Answer 11

• body organization: tissues
  ~ two germ layers: endoderm and ectoderm
• symmetry: radial (multiple planes of symmetry)
• habitat: aquatic, mostly marine
• body types: sessile polyp and motile medusa
  ~ some exclusively one, others both at certain times
• nerve net for sensation
• Cnidocytes: stinging cells with nematocyst (stinging capsule)
  ~ most present on tentacles and body
• incomplete digestive system
• gastrovascular cavity
• hydrostatic skeleton
• rely on simple diffusion for nutrient exchange and waste removal

Question 12

Phylum Cnidaria- Tissue Layers and Germ Layers

Answer 12

1. zygote cells divide to form multicellular blastula
2. one side of blastula pushes in (process called gastrulation) to form a gastrula
3. for now, the gastrula we’re considering have two germ layers- endoderm and ectoderm

epidermis- outer tissue layer formed from ectoderm

• gastrodermis- inner layer formed from ectoderm
• mesoglea- middle, gelatinous layer formed from both

Question 13

Phylum Cnidaria Class Anthozoa

Answer 13

• no medusa stage
• marine
• colonial or solitary
• some supported by hard skeletons
• two major subclasses based on planes of symmetry:
  ~ Hexacorallia (6-planes):
  - sea anemones, hard corals
  ~ Octocorallia (8-planes):
  - soft corals, sea pens, sea fans, etc

Question 14

Phylum Cnidaria Class Scyphozoa

Answer 14

• ‘true’ jellies
• pulsations for movement
• some have potent venom in tentacles to kill prey
• oral arms guide food into mouth
• digestion in gastric filaments and radial/marginal canals
• rhopalium: primitive structures for sensation and equilibrium
• Genus Aurelia

Question 15

Phylum Cnidaria Class Hydrozoa

Answer 15

• most alternate between both body forms where the polyp reproduces asexually and the medusa reproduces sexually
• marine and freshwater
• some exist as colonial organisms with multiple individual polyps living together as one “organism”
• Genus Hydra
  ~ small, tubular, freshwater
  ~ no medusa form; motile polyp
  ~ reproduce sexually and asexually
  - some monoecious (male and female gonads in the same individual) and others dioecious (separate sexes)
• Colonial Hydrozoans
  ~ Physalia (Portuguese Man of War)
  - “tentacles” have colonies of polyps
  - polyps are specialized for different functions (e.g. feeding, reproduction, etc)
  - pneumatocyst (air-filled sac) serves as a float to keep organism buoyant and to catch wind to move the organism

Question 16

Class Anthozoa Subclass Hexacorallia

Answer 16

• 6-fold symmetry
• Metridium
  ~ use acontia (white thread-like filaments) for defense
  ~ three regions
  - oral disc (tentacles & mouth)
  - column (main body)
  - pedal disc (bottom)
  ~ gastrovascular cavity divided into 6 radial chambers
  - contain septal filaments with nematocysts and digestive enzymes

Question 17

Phylum Ctenophora- Comb Jellies

Answer 17

• marine
• eight rows of evenly spaced ciliated bands (ctenes) used for motion
• capture prey with sticky adhesive from specialized cells
  ~ complete digestive system
• three layers
  ~ epidermis, gastrodermis, and collenchyma (middle layer)
• most monoecious

Question 18

Kingdom Animalia Phylum Platyhelminthes- “Flatworms” Distinguishing Characteristics

Answer 18

• body organization: organs
  ~ triploblastic
  
  • three germ layers that develop into three tissue layers
    - ectoderm—-> epidermis
    - endoderm—> gastrodermis
    - mesoderm—> mesoderm
  • acoelomate
• symmetry: bilateral
• first animals to cephalic (develop a head region)
• flat bodies allow for simple diffusion of nutrients and waste in/out of body
• digestion: gastrovascular cavity
  ~ incomplete digestive system
• excretion: flame cells for fluid balance and nitrogenous waste removal when simple diffusion won’t work
• reproduction: most monoecious

Question 19

Germ Layers and Protostomes

Answer 19

• there are two development layers (ectoderm and endoderm)
• there is a third layer (mesoderm) that develops in the middle of the other two layers
  ~ mesoderm gives rise to many internal structures and lining
• blastopore (the hole formed when the blastula is pushed in) has unique development paths
  ~ protostomes: blastopore becomes the mouth

Question 20

Coelom Types

Answer 20

• as the mesoderm develops, a fluid filled cavity called a coelom (sometimes) forms
  ~ acoelomate: no coelom
  ~ pseudocoelomate: a fake coelom forms between the mesoderm and endoderm
  ~ coelomate: a true coelom forms and is lined by mesoderm on both sides
• the coelom is a cavity that protects internal organs and sometimes acts as a hydrostatic skeleton for some taxa

Question 21

Phylum Platyhelminthes Class Turbellaria

Answer 21

• commonly referred to as “planarians”
• found in aquatic habitats (freshwater and marine) and moist terrestrial environments
• primarily carnivorous (consume other animals)
  ~ consume by sucking food into their retractable pharynx

Question 22

Class Turbellaria Genus Dugesia

Answer 22

• found in freshwater environments
• good example for many primitive organs
• sensory structures
  ~ auricle: sense environment via touch (thigmotaxis) and olfaction (chemotaxis)
  ~ eyespots: sense light (phototaxis)
  ~ cephalization
• locomotion
  ~ cilia located ventrally
  ~ rhabdites: secrete mucus for movement
  ~ circular, longitudinal, and torso- ventral muscles in body
• digestion:
  ~ highly branched gastrovascular cavity for digestion and nutrient transport
  
  • main chambers= trunks
  • smaller branches= diverticula
    ~ retractable pharynx
    ~ incomplete digestive system (no anus) so food has to come back out the same hole
• reproduction:
  ~ monoecious but reproduction is often sexual
  ~ can undergo transverse fission and regenerate
• excretion:
  ~ protonephridia (primitive kidney-like tissue) for osmoregulation
  - flame cells reside here
• nervous tissues:
  ~ cerebral ganglion
  ~ transverse nerve cords

Question 23

Phylum Platyhelminthes Class Trematoda

Answer 23

• also called “flukes”
• all trematodes (members of this class) are parasitic
  ~ internal parasites of mollusks and vertebrates
• use suckers to attach to host tissues from where they drain nutrients
• cuticle layer covers body to protect from host’s digestive enzymes
• built to reproduce
  ~ some have complex life cycles with many hosts
  ~ some monoecious

Question 24

Class Trematoda Genus Clonorchis

Answer 24

• digestion:
  ~ feed on host tissues
  ~ oral sucker anteriorly and ventral sucker on the ventral side to attach to host
  ~ mouth—> pharynx—> esophagus—> intestine
  ~ incomplete system- no anus
• excretion:
  ~ flame cells gather waste and drain it into the excretory bladder then out from there via the excretory pore
• reproduction
  ~ monoecious
• mall organs:
  ~ testes, vas efferens, vas deferens, seminal vesicle, genital pore
• female organs:
  ~ ovary: produces eggs
  ~ uterus: transports eggs to genital pore as they develop
  ~ yolk sac: provides yolk (full of nutrients for growth) to eggs

Question 25

Class Trematoda Genus Schistosoma- Human Blood Flukes

Answer 25

• infects > 200 million people
  ~ only malaria affects more people globally
• various species each infecting different blood vessel regions
• cause the disease schistosomiasis (aka snail fever)
• reproduction:
  ~ dioecious- strong sexual dimorphism

Question 26

Phylum Platyhelminthes Class Cestoda

Answer 26

• tapeworms
• most specialized endoparasitic flatworms
  ~ infects lower GI tract
• no mouth or digestive cavity
  ~ nutrients are directly absorbed from the host’s tissues via diffusion
• protective cuticle
• scolex (head region) has hooks and suckers for attachment
• body made up of repeating reproductive segments called proglottids
  ~ as proglottids mature and enlarge, they move towards the end of the tapeworm’s body
  ~ all proglottids connected by excretory canals and longitudinal nerves
• reproduction:
  ~ monoecious, but cross-fertilization is preferred
  ~ immature proglottids towards the scolex
  ~ gravid proglottids with fertilized eggs towards end of body ( so eggs can be released into host’s feces)
• Genus Taenia
  ~ beef tapeworm
  ~ infects human and cattle
• Genus Dipylidium
  ~ double- pored Dog Tapeworm
  ~ infects dogs and cats

Question 27

Phylum Rotifera

Answer 27

• most live in freshwater
• symmetry: bilateral
• pseudocoloemate
  ~ fluid inside serves as hydrostatic skeleton
• complete digestive system
• dioecious
  ~ sexual reproduction with internal fertilization
  ~ parthenogenesis
• cilia corona (anterior head structure) used for locomotion and feeding
• mouth with pharyngeal apparatus (mastax) and jaws for chewing prey or food particles

Question 28

Phylum Acanthoceohala

Answer 28

• “spiny-headed worms”
• parasitize guts of many vertebrate groups
• attach to host tissues using recurved hooks on proboscis
• lack mouth and digestive canal
  ~ nutrient absorption
• symmetry: bilateral
• dioecious
• pseudocoelomate

Question 29

Phylum Nematoda “Roundworms” Distinguishing Characteristics

Answer 29

- pseudocoelomates
~ serves as hydrostatic skeleton 
- symmetry: bilateral 
- complete digestive system 
- body covered in cuticle external to epidermis 
 - body organization: organ systems 
- nervous system: pharyngeal nerve ring 
- various diets 
~ many are endoparasites 
- sexual reproduction

Question 30

Phylum Nematoda Genus Ascaris

Answer 30

• human intestinal parasite
• dioecious
• cuticle composed of collagen
• complete digestive system

Question 31

Phylum Nematoda Genus Trichinella

Answer 31

• trichina worms or ‘pork worm’
• mammalian parasite
• causes disease trichinosis
  ~ passed via raw pork consumption
  ~ pregnant females burrow into intestine
• after birth, live young travel to muscle tissues to form dormant cysts which can survive fro years

Question 32

Phylum Nematoda

Answer 32

• pinworms
  ~ intestinal parasite
  ~ females lay eggs around the host’s anus
• Free-living Nematodes
  ~ ‘vinegar eels’
  
  • consume microbes in unfiltered vinegar
    ~ soil nematodes
  • consume microbes and small soil animals (other nematodes, etc)
  • can cause plant diseases

Question 33

Phylum Nematomorpha

Answer 33

• horsehair worms
• parasites of arthropods (many insects and crustaceans) when immature; adults free-living
• freshwater- dwelling
• external cuticle for protection
• simple nerve ring and muscles
• no other body systems
• pseudocoelomate
• dioecious

Question 34

Protostome Clades

Answer 34

• Lophotrochozoa
  1. Feed apparatus called a lophophore (ciliated crown of tentacles surrounding a mouth)
  2. trochophore larval stage as part of development
  ~ includes:
  
  • Platyhelminthes, Rotifera, Acanthocephala
  • Mollusca and Annelida
• Ecdysozoa
  ~ all animals in this clade grow via ecdysis (mottling their exoskeleton)
  ~ includes:
  
  • Nemtoda and Nematomorpha
  • Arthropoda