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Flashcards in Lecture Midterm 1 Deck (74):
1

What are the defining features of eukaryotes?

- Nucleus
- Cytoskeleton

2

Where did animals come from?

A single-celled ancestor called a choanoflagellate.

3

What are characteristics of the family Choanoflagellata?

- Heterotrophic
•Single flagellum with collar
•Suspension feeders
•Solitary or colonial
•Sister taxon of Metazoa
•Choan = funnel (Greek)

4

Describe Dinoflagellata.

•Usually 2 flagella
•Sulcus: longitudinal groove in which one flagellum lies
•Cingulum: a transverse groove that also has a flagellum
•Theca: rigid cellulose, often sculpted skeleton, occurs in the alveoli

•Auto- and Heterotrophs
•Important primary producers
•Red tides
•Zooxanthellae: Critical for corals•Fish kills
•Bioluminescence

5

Describe Ciliophora.

•Heterotrophic
•Multiple cilia for locomotion
•Alveolar vesicles
•Mitochondria with tubular cristae
•2 types of nuclei
•Carbs stored as glycogen

•Cilia
•Somatic and oral ciliature
•Kinetid(cilium w basal body)
•Kinety(row of kinetids)
•Kinetodesma
•(bundling of basal body fibrils)
•Metachronal waves
•Power, recovery strokes

6

How do Paramecium reproduce?

•Micronucleus– comparable to gonad “master copy”
•Macronucleus- working copies, contains millions of copies of certain genes
•Asexual fission: transverse - fission plane cuts across rows of kinetids
•Sexual conjugation: conjugation -involves meiosis and exchange of haploid micronuclei (macronuclei degenerate prior to conjugation)

7

What are some advantages of multicellularity?

•Division of labour
•Efficiency (environmental damage & loss)
•Increase in size
•Ecological advantages (predators)
•Metabolic advantages
•Complex tasks
•Information processing
•Biomechanics (speed)

8

What is the difference between Protozoans and Metazoans?

“Protozoans are eukaryotic, largely unicellular organisms that do not undergo tissue formation through the process of embryological layering."

“Metazoans are heterotrophic multicellular eukaryotes that undergo embryogenesis by way of tissue layering.”

9

What are the theories of Metazoan Origin?

Colonial Theory: Metazoa as derived from a colony of flagellated Protozoa, Cell division without separation (currently believed to be correct).

Syncytial Theory: Metazoa as derived from a multi-nucleate but unicellular like a ciliate protozoan, large multinucleate cells that eventually partitioned into compartments, and not much support.

10

What are apomorphies of Porifera?

Apomorphies
•Microvillar collars surround flagella(choanocytes) arising from single cells or syncytia
•Homologous with choanoflagellates??•Adults sessile and filter feeders, larval stages motile
•Collagen
•Skeletal elements(calcium carbonate and silicondioxide and collagen)
•Aquiferous system

11

What are apomorphies of Demospongiae

Apomorphies
•Spongin-based skeleton (a type of collagen)
•Siliceous tetraxons
•Spongocytes
•Most (>80%) sponges

12

What are the three general forms of Porifera (sponges)?

Asconoid (thin)
Syconoid (medium)
Leuconoid (large) - all large sponges are leuconoid.

13

What are apomorphies of Calcarea (Porifera)?

Apomorphies
•Calcium carbonate (calcite) spicules
•Won’t dissolve in HCL
•Large choanocytes
•Coeloblastula larva (hollow)

14

What are apomorphies of Homoscleramorpha (Porifera)?

Apomorphies
•Never with a spongin skeleton;
•Only sponge with basal lamina
•Shallow waters

15

What are apomorphies of Hexactinellida (glass sponges)

Apomorphies
- Siliceous spicules
- 6-rayed
- Syncytium
- Secondary silicification

16

Describe Placozoa.

•Discovered in 1883
•Cnidarians? Sponges? Ameboa?
•Phylum of one (?)
•4-5 cell types & several thousand cells
•Flattened body
•Ciliated upper and lower cells
•Fiber-syncytium (contractile);
•Amoeba-like motion
•Not polarised and can rip itself in two.
•Epithelial cells without basal lamina

17

What are apomorphies of Cnidaria?

Apomorphies
•Stinging cells (cnidocytes)
•Polyp adult and planula larva
•Nerve nets
•Longitudinal and circular muscle
•Endodermal gonads
•Circular mitochondrial DNA (anthozoans) & linear mtDNA

18

What is a Cnidae: Nematocyst?

•A secretion of cnidoblast
•For defense (inject toxins)
•For prey capture

19

What are the cell types of Cnidaria?

Cell Types
•Cnidocytes
•Muscle
•Nerve
•Glandular
•Interstitial
•Ciliated
•Sensory
•Germ

20

What are apomorphies of Anthozoa (Cnidaria) ?

•Polyps with pharynx
•Siphonoglyph
•3 cnidocytes

21

What are apomorphies of Scyphozoa?

Medusa with:
•Rhopalia(sense organs), which has
- Mesogleal, gastrodermal and epidermal components
- Gastrodermalstatocyst, mechano, photo, and chemoreceptor
•Gastric filaments
•Strobilation

22

What are apomorphies of Cubozoa?

•Small polyps lacking septa
•Cubic medusa
•Tentacles on pedalia at 4 corners of bell
•Four rhopalia with ocelli
•Velarium – powerful waterjet

23

What are apomorphies of Hydrozoa?

Apomorphies:
•Medusa with velum
•Endodermal cnidocytesabsent
•Gastrozooids: feeding
•Gonosooids: reproductive
•Dactylozooids: defense and prey capture

24

What are apomorphies of Ctenophora?

Biradial symmetry
•Diploblastic?? (tri)
•Aboral organ
•Ciliary rosettes
•Photocytes
•Ctene rows
•Collocytes

25

What are apomorphies of Bilateria?

Apomorphies
•Bilateral symmetry
•Mid-sagittal plane (l/r mirror images
•Dorsal and ventral sides)
•Cephalization
•Triploblasts(endo, ecto, mesoderm)
•Through gut
•Excretory organs

26

What are the three types of symmetry?

1. Radial symmetry: One main axis around which the various body parts are arranged.
2. Biradial symmetry: Only two planes can section animal into perfectly similar halves.
3. Bilateral symmetry: An axis passes from anterior to posterior. The midsagittal plane separates left from right.

27

What are apomorphies of Xenocoelomorpha?

Apomorphies
- No anus (lacking through gut)
- Epidermis with uniquecilia
- No discrete organs
- No larval forms

28

What are apomorphies of Protostomia?

Apomorphies
•Blastopore becomes the mouth
•Schizocoely(schiz = split)
•(coelom (body cavity) is formed by splitting the mesodermal embryonic tissue.)
•triploblastic organisms - three cell layers•ecto-, meso-, endo- derm

29

What are apomorphies of Spiralia?

Apomorphies
•Larval protonephridia (face outward to the environment)
•Chaetae
•Beta chitin

30

What is included in Protostomia?

•Spiralia: Annelids, mollusks, Bryozoans, Chaetognaths, Rotifers etc.
•Ecdysozoa: Moulting animals – arthropods, Nematodes

31

What are apomorphies of Platyhelminthes?

Apomorphies
•Multi-ciliated epidermis and gastrodermis
•Two cilia per protonephridial terminal cell

32

Describe the musculature of Platyhelimthes?

•Circular muscle
•Longitudinal muscle
•Dorsoventral muscle
•Muscular waves - swimming

33

What are Neoblasts?

- Adult stem cells.
•Pluripotent: ability to differentiate into all zygotic cell types.
•Likely even totipotent (differentiation into all zygotic cell types + extraembryonic tissues)

34

Describe the digestive system of Platyhelminthes.

•Mouth, no anus
•Sucking pharynx
•Lateral branches
•Phagocytic, gland cells
•Gastro-vascular

35

What are apomorphies of Neodermata?

Apomorphy
•Neodermis(or tegument): adaptation to parasiticlife style
•Protection from gut enzymes, absorption of nutrients from host
•Non-ciliated
•Syncytial
•Adult

36

What are apomorphies Neodermata, Trematoda?

Apomorphies:
•Flatworms or flukes,
•Larval epidermis is combination of ciliated cells and syncytial neodermis.
•Two or more hosts
•Molluscs are the primary hosts.
•Huge health problem for humans

37

What are apomorphies of Aspidogastrea (Trematoda)?

Apomorphies
•Large, complex ventral adult sucker.
•Aspido = shield
•Mostly fish and turtles

38

What are apomorphies of Digenea (flukes)?

Apomorphies
•Miracidium larva with transverse bands of ciliated cells.
•Intermediate (mollusc) and definitive (vert) hosts.

39

Describe the Digenean life cycle.

•1st intermediate host ‐ snail
•2nd intermediate host (if present) ‐arthropod or fish
•Definitive host is a vertebrate
•Definitive host = one in which the parasite reaches maturity and reproduces sexually

40

What are apomorphies of Cestoda (tapeworms)?

Apomorphies
•Gut absent
•Ciliated larval epidermis syncytial

41

What are apomorphies of Rotifera?

Apomorphies
•Ciliary corona on head
- “Wheel organ” = rota = L for wheel•Unpaired retrocerebral gland
•Secretes mucus to lubricate wheel•Female has vitellarium
- Syncytial structure produces eggs

42

What are apomorphies of Chaetognatha (arrow worms)?

Apomorphies
•Grasping spines
- Alpha-chitin, hollow,
- Capture prey, envenomate
- Encapsulated in a hood
•Ciliary fences (corona ciliata)
- sensing prey
•Double-walled lateral fins
•Stratified epidermis
- Chitinous cuticle occurs at the head
- Along rest of the ‘torpedo’ 3-5 layers thick

43

What are the parts of the Lophophorate body?

•Mesosome: coelomcontaining, lophophore
•Metasome: most of the body
•Zooecium: exoskeleton secreted by the metasome
•Coelomopores

44

What are apomorphies of Lophophores?

Apomorphies
•Introvert: The anterior part of the body forms an introvert, within which the lophophore and tentacles can be withdrawn
•Funicular system
•Colonial
•Multiciliated cells
•Coelomopores
- A cilliated groove in the mesothelium along which eggs move to be released to the environment

45

Describe Zooids.

Polymorphism:
•In some groups –eurystomes
•Autozooids– feeding zooids
•Heterozooids–non-feeding zooids
•Avicularia–jaw-like mechanism used for defense
•Vibracula-large cilia-like structure use to keep colony clean, sometimes for locomotion

46

What are the types of Bryozoan colonies?

- Stolonate: hydroid shaped
- Foliaceous – leaf-like
- Fruticose
- Encrusting (Most common)

47

What are characteristics of Brachiopoda?

•Lampshells (similarity to Romanoillamps)
•Marine benthic suspension feeders
•Live attached to rocks
•5+cm in size (large)
•Large lophophore
•~350 species today
•superficial resemblance to bivalves

48

What is the difference between Bivalve Molluscs and Brachiopods?

Bivalve Mollusc
•Valves are lateral (left and right)

Brachiopod
•Valves are dorsal and ventral

49

What are apomorphies of Brachiopoda?

Apomorphies
•Bivalve shell & mantle
•Brachia
- Calcareous lophophore support
•Heart is dorsal
•Digestive ceca

•Adductor muscle contraction pulls valves together and closes shell
•Abductor (diductor) muscles. Contraction opens the valves
•Pedicle(extension of the body wall) connects to the substrate

50

Describe Brachiopod morphology.

•valves are dorsal and ventral in brachiopods
•Inarticulata and Articulata
•presence or absence of hinge teeth and sockets
•most modern brachiopods are Articulata
•hinge that holds two valves together is more developed in Articulata
•Large lophophore
•Shell secreted by outer mantle edge (outgrowth of body wall)
•Pedicle: attachment stalk (symmetry)

51

What are apomorphies of Phoronida?

Apomorphies
•Corpuscular hemoglobin in hemalsystem
•An adaptation to life in anoxic or hypoxic conditions
- Lophophore extends up into the oxygenated water, but this water is not circulated to the remainder of the organism in the tube

52

Describe Phoronid morphology.

•Secretchitinous tubes - sediment particles are incorporated into the tube
•Never leave tube - closed posterior
•Cylindrical body
•Anterior lophophore
•Swollen posterior ampulla
•Coelom creates hydrostatic skeleton
•Muscle fibers allow movement inside tube
•Feeding: Use upstream collection system
•Lophophore can be autotomised

53

What are apomorphies of Annelida (Little Ring)?

Apomorphies
- Metamerism (segmentation)
•Septa divides fluid filled coelom
•Added sequentially (youngest is??)
•Echiura’s apparentlyun‐segmented body infact represents a series of fused segments
- Chaetae

54

What is Metamerism?

Structural plan in which the body is differentiated along its longitudinal axis into a series of units or segments, each containing elements of the chief systems of organs.

55

What are the three body regions of Annelids?

- Prostomium
- Metameres
- Pygidium

56

What do Metameres (of Annelids) contain?

•Pair of mesodermal somites with coelomic spaces
•Pair of nephridia (excretion)
•Pair of coelomoducts (ciliated excretory and reproductive channels)
•Pair of ganglia on a ventral nerve cord•Pair of appendages

57

What is the difference between Segmentation and Metamerism?

Segmentation
- Derived from the Ectoderm.
- Confined to only the ectoderm.

Metamerism
- Derived from the Mesoderm.
- Confined to ectoderm and mesoderm (not endoderm).

58

What are advantages of Metamerism?

•Build a large organism from a simple plan
•Effective servicing of major systems
•Enables flexible and/or complex movements•Loss of parts not fatal
•Opportunities for specialization

59

What is Tagmatization?

Metameres are grouped sometimes into tagmata. Tagmata are structurally differentiated groups of segments specialized to perform specific functions for the whole organism. Some polychaetes, but reaches greatest extent in Arthropoda (head, thorax, abdomen).

60

What are apomorphies of Errantia "Polychaeta"?

Apomorphies
•Parapodia: each of a number of paired muscular bristle-bearing appendages used in locomotion, sensation, or respiration.
•Nuchal organs: chemoreception ciliated pit or grove, light detection, food detection.
•Pedal ganglia: control parapodial movements.
•Pair of pygidial cirri: sensory appendage.

61

What are the three major lifestyles of Errantia "Polychaeta"?

- Burrowers
- Crawlers
- Swimmers

62

What are apomorphies of Sedentaria; Clitellata?

Apomorphies:
•Lack parapodia
•Clitellum: series of anterior segments enclosed in thick, glandular epidermis – girdle –reproductive structure

63

What are apomorphies of Hirudinomorpha?

Apomorphies
•Posterior sucker
•Dorsal anus anterior to sucker
•Superficial annulations: un‐segmented body with superficial marks
•No chetae
•Unpaired mid‐ventral gonopore
•Ectoparasitic: lives on surface of host
•Sensory papillae: specialised sense organs ‐small projecting discs in a ring around one annulation.

64

What are apomorphies of Echiura?

•Pair of anterior ventral chaetae
•2 posterior rings of chaetae (beta-chitin)
•Used for digging
•Echiura’s apparently un-segmented body in fact represents a series of fused segments
•Prostomium
•Prostomial and trunk coeloms (like sipunculans)
•Intestinal siphon (accessory gut – water bypasses the main gut)

65

What are apomorphies of Sipuncula (peanut worms)?

•Introvert
•Eversible (circular muscles)
•Introvert retractor muscles
•Te n t a c l e s
•Tentacular coelom
•J-shaped intestinal tract
•Intestinal ciliary groove (water shunt)
•Cuticle with scattered hooks
•Hemerythrin in cells

66

What are apomorphies of Mollusca?

Apomorphies
•Dorsal mantle with secreted chitin cuticle and calcareous spicules
•Radula
•Foot and paired pedal retractor muscles
•Bipectinate gills
•Tetraneural nervous system
•pair pedal nerve cords
•pair of visceral nerve cords

67

What are apomorphies of Aplacophora?

Apomorphies
•Cylindrical vermiform body
•Foot reduced
•Mantle with cuticle and spicules
•Solenogastres: live on branches of cnidarians
•Caudofoveata: burrowing in sediment

68

What are apomorphies Eumollusca?

Apomorphies
•Digestive ceca
•Coiled gut
•Complex radular musculature
•Odontophore with chondroidsupports

69

What are apomorphies of Polyplacophora?

Apomorphies
•GR poly-(many), plako-(tablet), and -phoros(bearing)•8 dorsal overlapping valves
•Valves have tegmentum and articulamentum layers
•Aesthetes
•sense organs embedded in the tegmentum of each valve

70

Describe the morphology of molluscs.

•Muscular foot
•Enrollment muscles: longitudinal - can roll self into a ball
•Bipectinate gills
•Inhalant and exhalant aperture are anterior and posterior, respectively

71

What are apomorphies of

Apomorphies
•One piece shell with periostracum and calcareous layers
•Mantle margins with 3 folds
•Crystalline style
•stiff mass in stomach and style sack of digestive enzymes
•Mantle spicules absent
•8 pairs of dorsoventral pedal retractor muscle

72

What are apomorphies of Gastropoda?

Apomorphies
•To r s i o n
•Usually coiled, asymmetrical
•Anterior mantle cavity
•Operculum
•Left gonad lost

73

What are the parts of a snail shell?

•Periostracum: proteinaceousouter layer
•Ostracum: prismatic layer -bricks are perpendicular to surface
•Hypostracum: plywood-like •Nacreous layer: mother of pearl

74

What are apomorphies of Bivalvia?

Apomorphies
•Bivalve shell with hinge
•Adductor muscles
•Radula lost
•Most are suspension feeders
•Siphons for inhalant and exhalant water
•Relatively long‐lived (150yrs)