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Organisms 2 Lab Exam > Lab 1 (Protozoa, Porifera, Cnidaria) > Flashcards

Lab 1 (Protozoa, Porifera, Cnidaria) Flashcards

1
Q

Why are these groups considered the more “primitive” animals?

A
  • They are single-celled organisms (protozoans)
  • They are multi-cellular animals (metazoan)
  • They either have a cellular-level organization or a tissue-level organization
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2
Q

Which group is the single-celled animals?

A

Protozoan

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3
Q

What characteristics do protozoans share?

A
  • There is no cell wall (this is found only in plant cells) but there is a cell membrane
  • Organelles are present, but no tissues or organs
  • Cytoskeleton, a network of protein fibres, is present
  • Live in water and/or moist soil
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4
Q

What are the three different groups of protozoans?

A

Amoeba
Paramecium
Trypanosoma

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5
Q

Explain the basics of the Amoeba

A
  • They live in fresh and salt water and in moist soil
  • They are bottom-dwellers that require a surface on which they glide
  • They feed on microscopic organisms (algae, bacteria, other protozoa)
  • Come in many shapes
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6
Q

What is the support in the Amoebas?

A
  • Outer cell membrane provides structure by enclosing and containing the cell contents, and acts as a semi-permeable environmental barrier through which water, nutrients and other products can flow
  • Beneath the cell membrane is a thin, clear layer of stiffened ectoplasm
  • Inner material is fluid endoplasm
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7
Q

What is ectoplasm strengthened by (in Amoebas)?

A

By a meshwork of fibrous actin (a protein found in muscles of other organisms)

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8
Q

Where do you find the organelles (in Amoebas)?

A

In the inner material

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9
Q

What does the endoplasm contain (in Amoebas)?

A

A network of protein fibres called the cytoskeleton

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10
Q

What is the movement in Amoebas?

A
  • They use extensions of their membranes called pseudopodia to move and change shape
  • Endoplasm flows into the leading tip of the pseudopod, where it is converted into stiffened ectoplasm
  • Ectoplasm at the “tail end” of the amoeba converts to streaming endoplasm to replenish the forward flow
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11
Q

What is the pseudopod used for in Amoeba movement?

A

To grasp a surface and pulls the rest of the cell forward

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12
Q

What is the feeding/digestion of the Amoebas?

A
  • They feed using a process called phagocytosis

- Waste products and excess water are removed through the cell membrane

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13
Q

What is phagocytosis?

A

Where they encircle food items with pseudopodia, forming water-filled food vacuoles that are later digested by enzymes

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14
Q

What is reproduction in Amoebas?

A
  • One of the largest organelles is the nucleus (which carries genetic material)
  • They produce via asexual reproduction
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15
Q

What is binary fission in the Amoebas?

A

They make a copy of their DNA, then create two new nuclei and splits into two new cells

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16
Q

Explain the basics of the Paramecium

A
  • They are active ciliate protozoans found in freshwater that contain a lot of organic matter
  • They are “slipper-shaped”
  • They feed on small particles like bacteria
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17
Q

What is the support in the Paramecium?

A
  • They have a thin, clear outer ectoplasm lying beneath the cell membrane
  • They have an inner endoplasm containing organelles and the cytoskeleton
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18
Q

What is the movement of the Paramecium?

A
  • The entire outer surface of the organism is covered with hair-like cilia
  • The oar-stroke action of the cilia moves the animal forward or in circles
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19
Q

What is the feeding/digestion of the Paramecium?

A
  • The oral groove is lined with cilia that draw food particles into the endoplasm (where food vacuoles are formed for later digestion)
  • Waste products and excess water are removed through the cell membrane
  • Large, round, contractile vacuoles are responsible for maintaining osmotic balance
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20
Q

What is osmotic balance?

A

pumping excess water out when needed

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21
Q

What is the reproduction of the Paramecium?

A
  • They have nucleus (micronucleus) and one or more micronuclei
  • Can reproduce asexually (binary fission) or sexually (conjugation)
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22
Q

What is conjugation?

A

Where DNA is swapped with another individual

23
Q

Explain the basics of the Trypanosoma

A
  • They are a parasite that can cause serious illness (sleeping sickness, Chagas’ disease)
  • They usually need an intermediate blood-sucking insect host in order to infect their human host
24
Q

What is the support of the Trypanosoma?

A
  • The same structures are present in Amoebas and Paramecium
25
Q

What is the movement of the Trypanosoma?

A
  • They have a whip-like organelle at one end called a flagellum (which moves the organism through its fluid environment)
26
Q

What is the feeding/digestion of the Trypanosoma?

A
  • They absorb their food from its hosts’ blood or other blood or other body fluids directly through its cell membrane
27
Q

What is the reproduction of the Trypanosoma?

A
  • Both the large nucleus and the kinetoplast contain DNA

- Reproduce via binary fission and sexual reproduction

28
Q

Explain the basics to the Phylum Porifera

A
  • Sponges
  • They are multi-cellular organisms
  • They have no tissues or organs
  • They are a collection of different kinds of cells that carry out specific tasks in an organized way
  • They have cellular-level organization
  • Adult sponges are sessile
  • Adult sponges may be colonial or solitary
29
Q

What are some characteristics shared by Poriferans?

A
  • Pore and canal system
  • Choanocytes
  • Spicules
  • Spongocoel and osculum
30
Q

What is the support of the sponges?

A
  • The body wall is reinforced with rigid, pointy, crystalline calcium carbonate structures called spicules
  • Other poriferans lack spicules (they rely on spongin for structural rigidity
31
Q

What are spicules?

A

They act as a skeleton, providing support

32
Q

What is the feeding/digestion of the sponges?

A
  • The body wall comprises a system of canals and pores
  • Finger-like projections point outward along the length of the body wall (these are radial canals)
  • Radial canals open into the body cavity, called the spongocoel, via small openings (apopyles)
  • Between adjacent radial canals called incurrent canals
  • Water (containing food particles and oxygen) first enter the incurrent canals
  • Then it passes through tiny openings (prosopyles) into the radial canals, moves through the apopyles, then into the spongocoel and finally out through the osculum, removing waste products
  • This process of water movement is facilitated by the action of choanocytes
33
Q

What are choanocytes?

A
  • Specialized flagellated cells that line the radial canals
  • The whip-like action of the flagella draws water in from the incurrent canals, trapping food particles and oxygen as water flows past
34
Q

What are the classes of the Phylum Cnidaria?

A

Hydrozoa
Scyphozoa
Anthozoa

35
Q

Explain the basics to the Phylum Cnidaria

A
  • Among the most primitive true multi-cellular organisms
  • Tissue level organization (lack true organs)
  • They all share a unique feature (stinging cells called cnidocytes)
  • They all are radially symmetrical
  • Two types of body forms (sessile polyp and free-swimming medusa)
  • Some display both forms while others only display one
36
Q

Explain the basics of the Class Hydrozoa

A
  • Small, solitary cnidarian
  • Only exists in the polyp form
  • Found in pools, streams and ponds (usually on the underside of aquatic vegetation)
37
Q

What is the support of the Class Hydrozoa?

A
  • The outer layers of tissue of the animal make up the epidermis or skin
  • This animal relies on internal water pressure to maintain its form
38
Q

What is the movement of the Class Hydrozoa?

A
  • Are sessile and attach to a surface using a sticky substance extruded from glands in the basal disk
  • They can move their body parts, including tentacles via a simple network of nerves that control muscle fibres
39
Q

What is the feeding/digestion of the Class Hydrozoa?

A
  • The circle of long tentacles at the other end should be evident, the mouth lies at their base
  • They can move, retract and extend their tentacles in response to environmental stimuli and are used in feeding
  • Tentacles are lined with groups of cnidocytes, each of which encloses a stinging organelle called a nematocyst
  • Food passed from the mouth into the gastrovascular cavity (where digestive enzymes partially digest the food)
  • Cells lining the cavity engulf what remains, and complete the digestion cellularly
  • Their digestion is a two-way street: there is no anus, so any waste/scraps are ejected from the mouth
40
Q

What are nematocysts?

A
  • Tiny capsules containing a coiled, threadlike stinging filament
  • Some are small, and are used simply to hold or entangle prey
  • Some are large, hollow and equipped with nasty barbs that embed in the prey item before they inject a paralyzing toxin
  • Helpless prey can then be safely dragged towards the mouth to be ingested
41
Q

What seems to trigger the firing of the nematocyst filament?

A

Disturbing the hair-like cnidocil on the outer edge of the cnidocyte

42
Q

What is the reproduction of the Class Hydrozoa?

A
  • Can use budding to reproduce asexually
  • A new animal, complete with tentacles and mouth, forms from the epidermis, then eventually breaks off from the parent
  • Can also reproduce sexually; some species posses both ovaries and testes (monoecious), while others are dioecious and have only one of the two
43
Q

Explain the basics of the Class Scyphozoa

A
  • True jellyfish
  • Made up of 94-99% of water
  • Their body parts are arranged in multiples of four so they are said to have tetramerous radial symmetry
  • Both polyp and medusa form
  • The medusa form are active swimmers
  • Both forms posses stinging cnidocytes
44
Q

What is the support of the moon jellyfish?

A
  • They parasol-shaped surface is called the bell
  • Hydrostatic skeleton allows it to maintain its shape
  • The outer margin is divided into sections; at each junction there is a bundle of sensory structures called rhopalia
45
Q

What is a rhopalia?

A

Consists of a statocyst and an ocellus (used for balance/orientation and light perception, respectively)

46
Q

What is the movement of the moon jellyfish?

A
  • A simple, decentralized nervous system controls muscle fibres that move the animals bell and allow it to swim in the water column
  • The same system controls the tentacles
47
Q

What is the feeding/digestion of the moon jellyfish?

A
  • Along the margin are many small tentacles; these should not be confused with the four large oral arms
  • The tentacles are used to filter tiny prey towards mucous on the margin; prey are collected by the trough-shaped oral arms which direct food to the mouth
  • The mouth opens into a short gullet, which leads to the stomach
  • Four gastric pushes extend from the stomach
  • These structures can be indistinct by themselves, but they also contain the gonads, which are horseshoe shaped and clearly visible
  • Near the pushes are thin gastric filaments, which are lined with cnidocytes; these subdue uncooperative prey before digestion takes place in the gastrovascular cavity
48
Q

What is the reproduction of the moon jellyfish?

A
  • They are dioecious and fertilization takes place externally, after the gonads shed sperms or eggs from the gastric pouches; these are discharged through the mouth
  • Young embryos develop in the folds of the oral arms, until, as ciliated larvae, they escape the parent and attach to a substrate.
  • There, the larva develops into a tiny sessile polyp called a scyphistoma
  • The scyphistoma becomes a multi-tiered strobing, form which tiny medusae called ephyra bud off
  • The ephyra mature to become adult jellyfish
49
Q

Explain the basics of the Class Anthozoa

A
  • Sea anemone
  • Marine animal that can live comfortably in intertidal zones as well as depths of up to 75m
  • Only the polyp form
50
Q

What is the support of the sea anemone?

A
  • The body has 3 main regions
    1) Oral disc (tentacles and mouth are located)
    2) Cylindrical column (forms the main body of the animal)
    3) Basal disc (the animal attaches itself to a substrate using sticky glandular secretions)
  • Hydrostatic skeleton
51
Q

What is the movement of the sea anemone?

A
  • Strong muscles running the length of the column allows the anemone to retract or extend on response to stimuli
  • Muscles also control the tentacles
  • Although the anemone is sessile, it can glide very slowly on the basal disc
52
Q

What is the feeding/digestion of the sea anemone?

A
  • Tentacles, armed with cnidocytes, capture prey
  • Food is then drawn into the mouth, where it then passes through the pharynx and into the gastrovascular cavity, where digestion takes place
  • Waste goes back out the mouth
53
Q

What is the reproduction of the sea anemone?

A
  • Gonads resembling thin stacks of small coins are visible on either side of the pharynx
  • Sex cells are released from these and pass through the mouth
  • Fertilization is external
  • Fertilized eggs hatch tiny larvae that settle to the substrate and turn into single polyps

Organisms 2 Lab Exam (5 decks)

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