Invertebrates Flashcards
1
Q
Animals are part of the clade:
Closest relative
A
Opisthokonts
Closest relative: Choanoflagellates
2
Q
Early milestones in animal diversification
A
Oldest animal fossil: 575Mya
DNA divergence: Suggest 850 Mya
3
Q
When did most species arise?
A
Cambrian explosion: 542-525 Mya
4
Q
Mal’s favourite
A
Hallucigenia
Spined worm
Similar to our velvet worm today
5
Q
4 branches of phylogenetic tree
A
1) Parazoa
2) Eumetazoa
3) Lophotrochozoa
4) Ecdysozoa
6
Q
Clade Porifera
A
Part of Parazoa "Pore-bearers" - sponges Multicellular, lack true tissue Filter/suspension feeders Asexual/sexual reproduction Vet significance: Drug discovery
7
Q
Poriferan structure
A
Sponge structure Water diffuses through membrane Contains Choanocycts Engulf by phagocytosis Water movement out the top
8
Q
Choanocysts
A
Create a current that draws water in through the porocytes
9
Q
Clade Eumetazoa divided into 2 clades
A
1) Radiata
2) Bilateria
10
Q
Radial Symmetry
A
- Many surgical plane forms symmetry
- Cutting oral to anus in many planes will all form symmetry
11
Q
Bilateral Symmetry
A
- Only 1 surgical plane forms symmetry
12
Q
Example of Radial Symmetry
A
Phylum Cnidarians “nettle animals”
13
Q
Cnidarians are: (4)
A
- true tissues
- Radial symmetry
- diploblastic
- all venomous
14
Q
Cnidarias diploblastic tissue (2)
A
1) Epidermis (ectoderm)
2) Gastrodermis (endoderm)
15
Q
What type of gastrovascular cavity do Cnidarians have?
A
Blind gastrovascular tract
- mouth doesn’t open to anus
16
Q
Compare/contrast gastrointestinal tract of sponges, cnidarians, animals
A
Sponges: have spongocoel - cavity containing seal water
Cnidarians: Simple gastro-tract surrounded by tentacles
Animals: Contain have gastrointestinal tract
17
Q
Cnidocil
A
Stinging sites: spikes on the outer surface which is a trigger for cnidocyte
18
Q
Cnidocyte
A
stinging portion which discharges threat to attach predator
19
Q
4 clades of Cnidarian Diversity
A
[CASH]
1) Cubozoa
2) Anthozoa
3) Scyphozoa
4) Hydrozoa
20
Q
Cubozoa
A
- hydrozoans
- poly dominant
21
Q
Anthozoa
A
- Anemones and corals
- Sessile polyps
22
Q
Scyphozoa
A
- Jellyfish
- Medusa dominant
23
Q
Why were Hydrozoa (hydra) used as a model?
A
1) Regeneration of tissue
2) Asexual reproduction by budding
3) Staining of live tissue
4) Eyeless animals can respond to light
24
Q
Box Jellyfish
A
- ambush predator
- highly venomous (neurotoxin)
- lethal to humans
- nematocysts fire on contact with skin
Treatment: Vinegar to disable nematocysts
25
Bilateria has allowed for (2)
1) Forward, directed movements
| 2) Cephalization
26
Cephalization
Formation of a head region
Results in:
1) sensory structures
- can respond to environmental gradients
27
Are bilateria monoblastic, diblastic, or triploblastic organisms
Triploblastic
28
Triploblastic
Ectoderm (outside)
Mesoderm (Middle)
Endoderm (inside)
29
Are Cnidaria monoblastic, diploblastic, or triploblastic?
Diploblastic
30
Ectoderm
Brain, nerves, peripheral nerves
| Skin, hair, nails, mouth lining, tooth enamel
31
Mesoderm
Kidneys, gonads, circulatory system, muscles, notochord, and body cavity
32
Endoderm
Lining of GI tract, respiratory tubes, liver, pancreas
33
Clades of Bilateria
1) Lophotrochozoa
2) Ecdysozoa
3) Deuterostomia
34
Phyla of Lophotrochozoa (4)
[PAAM]
1) Platyhelminths
2) Annelida
3) Acanthocephela
4) Mollusca
35
4 classes of Platyhelminths
[CTTM]
1) Cestoda
2) Trematoda
3) Turbellaria
4) Monogenea
36
Turbellaria
Class of Platyhelminths
- Free living
- commensal
- some parasitic
- ciliated epidermis for locomotion
- acoelomate
- Excretory system - Protonephridial
37
Protonephridial system
- waste material drains from body to excretory cells called flame cells
38
Metanephridia system
- filtrate is filtered from blood in special filtration sites (ex, kidney)
39
Planaria
- models for regeneration
- worm contain 279 pieces - each can regenerate an entire worm
- each cell is a neuroblast - can develop onto many different tissues
40
Syncytial
Cells have merged to form a super-cell, but contain many nuclei
41
Flukes and Tapeworms are aways (1)
Parasitic/commensal organisms
42
Monogenea
Parasites of Fish
Obligate ecto-parasites
Life cycle: Eggs laid on host, fall off host, hatch, larvae seeks new host
43
Gyrodactylus
Russian doll life cycle
Only gives rise to 2-4 offspring
Offspring already contained within parent
44
Trematoda
```
Class of platyhelminths
obligate parasites
Adults live in intestine
- attach to mucosal wall
Hermaphroditic
Complex life cycle with 2 or more hosts
```
45
Fasciola hepatica
Trematoda
Fluke of sheet, cattle, grazing animals, us
Liver fluke
Anaemia due to blood sucking nature
46
Fasciola hepatica life cycle
1) Eggs pass in faeces
2) (Larval stage) Miracidium in water passed to snail
3) Sporocysts, redia, cercaria by Asex, repro.
4) Encystment (metacercaria)
5) Eaten by host (ex, sheep)
47
How do Fasciola hepatica and Schistosomes differ?
Fasciola: Hermaphroditic
Schistosomes: 2 different sexes (dioecious)
48
Similarities between Fasciola and Schistosomes
1) Both infect snails as intermediate hosts
| 2) Change in larval stages due to asexual reproduction
49
Cestoda
```
Tapeworms
Parasite of SI
Class of Platyhelminths
No mouth, digestive tract, or anus
Repro. system replicated as chain
```
50
5 structures of Cestodes
1) Scolex
2) Neck
3) Immature proglottids
4) Mature proglottids
5) Gravid proglottids
6) Strobila
51
Examples of tapeworms
```
Taenia Sagitta (cows)
Taenia Solium (pigs)
```
52
Life cycle of tapewors
1) Gravid proglottids leave host in faeces
2) Intermediate host ingests
3) Cysts in intermediate host muscle / larval scolex attaches
4) Definitive host eats infected intermediate host
53
Echinococcus granulosus
- class Cestodes of Platyhelminth phylum
- Hydatid tapeworm
- Hermaphroditic
- Definitive host: dog, dingo, fox
- Intermediate host: sheep, cow, marsupials, humans
- Transmission: through ingestion of hydatid cysts
54
Clade Lophotrochozoans contains four phylums
1) Playhelminths (no body cavity)
2) Mollusca (body cavity)
3) Annelida (body cavity)
4) Acanthocephala
55
3 types of body cavities
1) Acoelomate
2) Coelomate
3) Pseudocoelomate
56
Acoelomate
No body cavity
| Body is solid
57
Coelomate
```
Fluid filled cavity lies between gut and body wall
Lined by mesoderm on both sides
1) Separate control of organs
2) Circulatory system - larger size
3) Greater body complexity
```
58
Pseudocoelomate
Intermediate form of body structure
| Lined by mesoderm on one side only
59
Examples of Acoelomate, coelomate, and pseudocoelomate
Acoelomate: Platyhelminths
Coelomate: Annelids, Mollusca
Pseudocoelomate: Nematoda
60
```
Annelida are (segmented/non-segmented)
Example: (1)
```
Segmented
| Example) Leaches
61
What are two benefits of segmentation in annelids?
1) Better control of body secretions
| 2) Diversification
62
Benefits of having body cavity
Coelomate
1) separate movement of body wall and organs
2) space for complex organs
3) storage for eggs and sperm
4) coelomic fluid protects internal organs
5) circulatory function and oxygen movement
6) wate removal
7) function as hydrostatic skeleton
63
Phylum Acanthocephala
Part of clade locotrophozoans
"thorny headed worms"
All parasitic
No gastrointestinal tract (acoelomate)
Intermediate hosts: Arthropods
Definitive hosts: Vertebrate
64
Life cycle of Acanthocephala
1) Eggs passed in faeces
2) Eggs ingested by beetle larvae
3) Pig ingests beetle larvae
4) Adult parasite lives in SI of Pig
Macracanthorhynchus hirudinaceous
65
Clade Ecdysozoans contains 2 phylums
1) Nematoda
| 2) Arthropda
66
What does Ecdys- mean?
- shedding exoskeleton
67
Nematoda
```
Roundworms
Psuedocoelomate body cavity
Longitudinal muscles only
No respiratory/circulatory system
Non-segmented, cylindrical body
Internal transport via body fluid
Complete gut - separate mouth/anus
Dioecious
```
68
Dioecious
Seperate male and female individuals
| Organism only contains male or female reproductive structures
69
Are Nematoday monoblastic, diblastic, or triploblastic?
Triploblastic
| Psuedocoelomate body cavity
70
How do Nematodes grow?
Grow through moulting
| Egg, 4 larval stages, adult
71
What allows Nematodes to be great parasites?
- very thick cuticle
| - Cuticle has capacity to correct itself
72
What is the model organism for Nematodes?
C. elegans
| Caenorhabditis elegans
73
C. elegans
Model organism of nematodes
Few cell types
First multicellular organisms to be sequenced
959 somatic cells in adult hermaphrodite
74
Important nematodes (2)
Nematodes - Roundworms
1) C. elegans
2) Haemonchus contortus
3) Ascarids
75
Types of Ascarids (4)
Ascarids = roundworms
1) Ascaris suum (pigs)
2) Ascaris lumbercoides (humans)
3) ParAscaris equi (horses)
4) Toxocara canis (dogs)
76
Types of Hookworms (2)
Hookworms are nematodes - roundworms
1) Ancylostoma caninum (dog/human hookworm)
2) Necator americanus (human)
77
General Ascarid information
Large intestinal worm
Occlude intestine
Females lay desiccation resistant eggs
78
Parascaris equorum
1) eggs in faeces
2) eggs ingested my horse
3) larvae hatch in SI
4) Larvae burry into SI wall, find blood ves.
5) Migrate to Lungs
6) Burst through alveoli to Trachea
7) Swallowed once in trachea
8) Adults live in SI
9) Eggs in faeces
79
What are the effects of Parascaris on equine host? (5)
1) Pneumonia due to migrating larvae
2) Loss of energy
3) Colic
4) Intestinal perforation
5) Intestinal obstruction
80
Pinworms
Enterobius vermicularis - humans
| Oxyuris equi - horses
81
Dog Heartworm
Dirofilaria immitis
82
Dirofilaria immitus
Dog heartworm
Adult worms: live in the right side of heart and pulmonary artery
Also found in cats
Cause immune associated problems
83
Dog Heartworm lifecycle
Dirofilaria immitis
1) Microfilaria (L1's) are ingested by mosquito
2) Mosquito transmits vector with blood mean
3) L1's develop into L3's in muscle in mosquito
4) L3's migrate to mosquito salivary gland
5) Bite host
84
What is the infective agent in dog heartworm
Dirofilaria immitis
Microfilaria (L3's) are infective agent
L3's are in mosquito salivary gland
85
Lymphatic filariasis is caused by
Wuchereria bancrofti - causes elaphantitis in humans
- enlargement of the legs (edoema)
- enlargement of the scrotum (edoema)
86
What are three different types of muscle parasites?
1) Taenia sagitta (cows)
2) Taenia solium (pigs)
3) Trichinella spiralis (pigs)
87
Trichinella spiralis
muscle worm in pigs
| intracellular parasite
88
Trichinella spiralis life cycle
1) ingestion of undercooked meat
2) Larvae released into SI
3) Adults in SI
4) Larvae deposited in mucosa
5) Encyst larvae in muscle of host
