Lab Exam Review - Protozoa

What is the function of the cell membrane?

The cell membrane is semi permeable to facilitate the exchange of products.

What is ectoplasm?

Ectoplasm is the substance located beneath the cell membrane, made of fibrous actin.

What does endoplasm contain?

Endoplasm contains the cytoskeleton and organelles.

What are amoebozoa three support structures

Endoplasm, ectoplasm, cell membrane

What is amoebozoa structure of locomotion

Psuedopodia

Amoebozoa digestive system structures

Phagocytosis and water filled food vacuoles

Amoebozoa reproduction

Binary fission

What is binary fission

Organism duplicates its genetic material, divides into two parts, new organism has each copy of DNA

Three support structures of Paramecium

Cell membrane, ectoplasm, endoplasm

Paramecium movement

Cilia makes oar-stroke action that moves organism forward or in circles

Paramecium digestive system structures

CIliate oral groove, food vacuoles in endoplasm, cell membrane, contractile vacuoles

Paramecium reproduction

Asexual — binary fission

Sexual — conjugation

What is conjugation

A form of sexual reproduction used by bacteria or protists to directly exchange genetic material, usually in the form of a plasmid, between two organisms via a pilus (e.g. paramecium)

Digestive system of Trypanosoma

Absorb food from host’s blood or other body fluid directly through cell membrane

Movement of trypanosoma

Use flagella to move through fluid environment

Where do trypanosomes have genetic material

DNA and Kinetoplast

What is the kinetoplast

Specialized structure within the mitochondria containing kinetoplast DNA (kDNA) that can be replicated for asexual reproduction

What are the shared structures of all porifera

• Pore and canal systems

• Choanocytes

• Spongocoel and osculum

• Spicules and/or spongin

What are choanocytes

specialized flagellated cells that live in the chambers of porifera — generate water flow with flagellum to trap food particles

What is the spongocoel

large central water-filled cavity of sponges

What are spicules

Tiny rigid needle-like structures composed of silica or calcium carbonate that form the internal skeletal framework of sponges — defense against predators

What is spongin

Soft, flexible, fibrous collagen protein — allows for flexibility

Feeding/digestion structures of scypha sp. sponges

• Adjacent radial canals

• Apopyles

• Spongocoel

• Incurrent canals

• Osculum

• Choanocytes — line the radial canals

What are apopyles in sponges

Pores that allow water to pass out of the flagellated chamber (radial canal) into the central spongocoel

What are the common characteristics of all cnidara

• Tissue level organization

• Cnidocytes

• Radial symmetry

What are cnidocytes

Specializd stinging cells of phylum cnidaria

What are the three classes of cnidaria examined in the lab

1. Hydrozoa

2. Scyphozoa

3. Anthozoa

Structures of support of hydrozoa

1. Epidermis

2. Hydrostatic skeleton

Structures of movement for Hydrozoa

1. Sessile, attach to substrate using sticky substance extruded from basal disk glands

2. Move tentacles and other body parts via network of nerves

Feeding of hydrozoa sp.

cnidocil disturbed by movement of prey which triggers nematocyst containing cnidocytes that line tentacles to paralyze and grasp prey and draw towards mouth that lies at the base

Digestion of hydrozoa sp.

Food travels from mouth into gastrovascular cavity where digestive enzymes partially digest food, and food that is left is englufed by cells lining the cavity

Forms of reproduction for Hydra sp.

1. Asexual = budding

2. Sexual = direct gamete fertilization (can be dioecious or monoecious)

What is budding

An asexual form of reproduction in which a new organism is formed from a small part of the “parent” organism’s body

What are nematocysts

Specialized cell contained by cnidocytes in cnidaria that have barbed or venemous coiled thread that can be projected in defense against predation

Life cycle of hydra

Only a polyp

Which sponge species is examined in the lab

Scypha sp.

Characteristics of class scyphozoa

1. Tetramerous radial symmetry

2. Polyp and medusa life stages

What species of scyphozoa is examined in the lab

Aurelia aurita

What is the sensory structure of Aurelia aurita?

Rhophalia

Where are the rhopalia located

Junctions of the margin

Support structure of Aurelia aurita

1. Bell

2. Hydrostatic skeleton

3. Outer margin

Aurelia aurita movement

decentralized nervous system control bell and tentacle movement

Aurelia aurita feeding/digestion

Tentacles line the margin, bring prey towards mucus (traps prey), oral arms direct prey towards mouth — then into the gastric pouches

• gastric filaments lined by cnidocytes subdue prey and send to gastrovascular cavity for digestion

• Waste excreted from central mouth

Aurelia aurita reproduction

Dioecious — sperm or eggs release from gastric pouches, discharged through mouth

Aurelia aurita life cycle

1. Ciliated larvae

2. Scyphistoma

3. Strobila

4. Ephyra

5. Mature jellyfish

Class anthozoa

Sea anemone

Life stage of anthozoa/sea anemone

Polyp only

Support structure of sea anemone

1. Oral disc

2. Basal disc

3. Hydrostatic skeleton

Sea anenome Feeding/digestion

• Tentacles lined with cnidocytes to capture prey

• Prey led toward mouth then into pharynx, then into gastrovascular cavity for digestion

• Excrete through mouth

Sean anenome Reproduction

• Gonads line either side of the pharynx

• Sex cells released from gonads

• Fertilized eggs hatch larvae which settle on substrate

• Larvae develop into polyps

• Can also reproduce asexually (e.g. fission, budding)

Platyhelminthes, nematoda, mollusca characteristics

• Bilateral symmetry

• Cephalization

• Triploblastic

• Peritoneum lines coelom

Platyhelminthe class examined in lab

Turbellaria — flatworm

Turbellaria organ systems

Reproductive and digestive

• No circulatory system

How does the class Turbellaria breathe?

O2 directly diffuses through epidermis

Turbellaria movement

• Glide on mucus

• Use cilia to direct movement

Turbellaria feeding/digestion

• Mouth located posteriorly on ventral side

• Tube in the middle is the muscular pharynx

• Pharynx can be everted from body, impale food/prey, bring toward mouth and into intestines

• Triclad — one anterior trunk intestine and two posterior

  • THREE INTESTINAL BRANCHES

• Waste ejected from mouth (blind gut)

What are all the characteristics that chordata exhibit at some point in their life cycle?

1. Notochord

2. Pharyngeal slits/pouches

3. Endostyle

4. Dorsal hollow nerve cord

5. Postanal tail

Nervous/sensory structure of planaria/Turbellaria

• Triangular head containing ganglia

• Body covered in chemoreceptors and tactile cells

• Auricles on either side of head (olfaction and touch)

• Eyespots for light sensitivty

Planaria reproduction

Sexual — monoecious; exchange sex cells

Asexual — transverse fission

Three segments of cestoda (tapeworm)

1. Scolex (head)

2. Neck

3. Strobila (body)

Tapeworm (cestoda) sensory structures

• Scolex contains ganglia

• Body covered in chemoreceptors

Tapeworm (cestoda) feeding/digestion

No digestive or intestine system

• Scolex has suckers and rostellum (hooks) to attach to host’s intestine

• Absorbs nutrients directly through proglottids

Reproduction in Class Cestoda/tapeworm

• Proglottids form by strobilation

• Tapeworm has pair of ovaries, many testes, and genital pore

• Fertilize by cross fertilization

• Fertilized uterus within proglottid develop embryos

• Gravid embryonic proglottids break off and shed in host’s feces

  • Other animals eat tapeworm infested feces and become infected, continuing life cycle

Phylum Nematoda

Roundworm

Sexual dimorphism of roundworm

M have hooked posterior

F are bigger and plumper

What constitutes a complete digestive system

Mouth and anus

Roundworm feeding/digestion

• Anterior end of roundworm = mouth

• Mouth ingests food from digested food of host’s intestine

• Food goes from pharynx to intestine

• Waste excreted from anus

Components of the female roundworm reproductive system

• Genital pore

• Uteri

• Oviduct

• Ovaries

Components of male roundworm reproductive system

• Seminal vesicle

• Vas deferens

• Testes

Components shared by most (not all) molluscs

• Foot for locomotion

• Two shells (valves)

• Mantle that secretes shells

• Mantle enclosing mantle cavity enclosing gills

• Open circulatory system + heart

• Complete digestive system

• Cephalization

Support structure of marine mussel (bivalve)

• Umbo

• Hinge ligament

• Adductor muscles

• Palial muscle (marked by palial line)

Respiration of marine mussel (bivalve)

• Beneath mantles are gills

• Gills have ridges and folds maximizing surface area for gas exchange

• Cilia on mantle and gills keeps water flowing into mantle cavity

Locomotion of mussel (bivalve)

• Foot

• Anterior and posterior adductors

• Anterior and posterior foot retractors

Feeding/digestion of mussel (bivalve)

• Labial palps direct food to mouth

• Mouth → pharynx → stomach

• Stomach surronded by digestive glands (pseudoliver)

• Stomach narrows into coiled intestine that passes through heart and connects to rectum and anus

Mussel circulation

Open circulatory system

• Oxygenated blood bathe organs

Blood: heart → kidneys → gills → heart

Mussel (bivalve) reproduction

Much of visceral mass made up of gonads

• M release sperm that is taken up by incurrent siphon of female

• Brood chamber/gills harbor developing embryos

• Then release into water as larvae

Larval stage of mussels (bivalves)

Glochida

• Parasitic

• Bea hooks allowing them to attach to passing fish

• Dispersal stage

Are mussels dioecious or monoecious

Dioecious, because they possess gonads

Gastropoda seen in lab

Land snail

Which opening allows the land snail to conduct gas exchange

Pneumostome

Sensory structure of land snail (gastropoda)

• Eye

• Eye stalks

• Smaller tentacles used in tactile and chemoreception

Feeding/digestion of land snail (gastropoda)

• Mouth

• Radula (mechanical grinding)

• Food travels mouth → stomach → intestine → anus

• Digestive gland

Reproduction of snail (gastropod)

Most snails are monoecious and self-fertilizing

Cephalopoda viewed in lab

Squid

Ventral head and tentacles of squid are a modification of which structure of bivalva?

Ventral foot (homologous structure)

Hard outer shell of bivalva modified to what in squid?

Pen → acts as flexible skeleton to keep shape of squid

Is the squid eye homologous or analogous to human eye?

Analogous

What are the chromatophores

Specialized pigment cells of squid that allow them to rapidly change color

Sensory structures of squid

• Complex eye

• Head at ventral end

• Chromatophores (respond to external stimuli)

Locomotion of squid

• Siphon under mantle at posterior end used for jet propulsion

• Two fins at dorsal end for maneuverability

What is the pen of the squid

The reduced and modified outer shell of other molluscs reduces to the pen — internal structural skeleton

What are the 10 appendages of the squid head

8 short arms + 2 long tentacles

Structural support of squid

• Mantle provides hard cartilaginous support

• Pen provides skeletal support

• Mantle uses muscular contractions to control the flow of water into the mantle cavity

Respiration/circulation of squid

• Two feathery gills attach to the brachial hearts (2)

• Central systemic heart supplies blood to rest of body

What are the three sections of squid heart

two brachial hearts + one central systemic heart

Squid form of defense from predators

Ejecting ink from ink sac out of the siphon

Female squid reproductive system

• Ovary

• Oviductal gland

• Nidamental gland

• Oviduct

• Sperm pouch

Male squid reproductive system

• Testes

• Vas deferens

• Penis

Reproductive process of squid

Male squid transfers sperm to female pouch who brings eggs toward pouch via oviduct-siphon and fertilizes eggs in pouch

Digestive system components of squid

• Stomach

• Intestine from stomach to rectum

• Caecum to digest bolus from stomach

• Mouth covered by beak

• Arms bring prey caught by tentacles toward the mouth

• Waste excreted through siphon