Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Invertebrates > Platyhelminthes (flatworms) > Flashcards

Platyhelminthes (flatworms) Flashcards

1
Q

Body symmetry / layers / cleavage

A
  • Bilateral
  • 3 body layers (triploblastic)
  • Spiral cleavage - protostome: mouth develops first
  • within spiralia group on evolutionary tree
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Body structure

A

Acoelomate (no body cavity/coelom

Dorso-ventrally flattened

High surface area to body ratio

some organ development

No circulatory system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cephalization

A

concentration of nervous tissue at one end (anterior end)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why must they be aquatic?

A

Susceptible to drying because they are so thin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what percentage of platyhelminthes parasitic?

A

75%

rest are free-living form

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

The gut of free-living forms

A

Gut has one opening

can be simple or complex

pharynx serves as anus and mouth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are oracles? (body structure)

A

stick out of head and detect chemical signals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Waste excretory system name

A

Protonephridia

simple system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Waste excretory system mechanism

A
  • Protonephridia
  • Flame bulbs: branched guts that end in ‘bulbs’ with flagella on the end.
  • Flagella waft materials and waste products through a tube system,
  • Absorb anything that is useful and excrete anything that isn’t*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How are platyhelminths linked to Xenacoelomorpha?

A

Xenacoelomorpha are basal bilaterians once thought to be platyhelminths because of their similar body structure

separate sister group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Flatworm body movement

A

Longitudinal and circular muscles around the body

Cilia and gland cells - produce mucus - allow movement

Some ungulate body for movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Nervous system

A

Nerve branches run down body from anterior to posterior

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

mechanisms of sight

A

Negatively phototactic (move away from light)
Form of protection (avoiding drying out)

Simple eyes -Detect light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Reproductive organs

A

Hermaphrodite
both male and female reproductive organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Regeneration

A

Can reform parts of body

different size cuts create different regenerations

A smaller cut leads to two heads forming instead of head and tail.

further down the animal regeneration takes longer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Mechanism of regeneration

A
  • Neoblasts (stem cells) activated to reform lost tissue
  • Activated by some sort of chemical gradient
  • A possible explanation of why lower down the body regeneration is slower (lower concentrations of neoblasts?)
17
Q

Thompson and McConnell experiment - Can memory be transferred chemically?

A

Trained flatworms with electric shocks and bright light

Chopped up and found that new regeneration also responded to light

Same happened when trained flatworm was fed to other animal

Suggested memory was transferred chemically
Possibly some bias in the experiment

More recent experiments suggest that memory can be transferred or stored after regeneration.

18
Q

Sexual reproduction of flatworms

A

Pair up and have mutual exchange of sperm

19
Q

What is penis fencing?

A

Fertilised offspring need investment so some species fight so that one can get the sperm in before the other

Acting as a male is less costly than being a female

20
Q

Parasitic adaptations (modification of body to adapt)

A
  • Loss of unwanted organs
  • Penetration devices - some way of getting into host
  • Attachment devices - a way of hanging onto the host
  • Protective device - to prevent themselves from being attacked by the host
  • Transmission via a vector - complex life cycle
  • Production of eggs in large numbers
21
Q

Flukes (trematodes): Tegument

A
  • Non- ciliated syncytium: Cells without any boundaries
  • Protective coat
  • Allows diffusion and some nutrient uptake
  • Protects the parasite from host immune factors and serves as an absorptive surface for the acquisition of nutrients
22
Q

Fluke pharynx

A

used to feed - strong sucker

23
Q

Fluke reproduction

A

Most of the animal is dedicated to reproducing

produces 10,00 - 100,000 x more eggs than free living flatworm

hermaphrodite

24
Q

Flukes: excretion / nervous system

A

Protonephridia - simple excretory system

simple nervous system

25
Q

Generalised life cycle of a fluke

A
  • Eggs released from difinitive host in faeces, urine and sputum (spit) - often into water
  • Miracidium forms (ciliated larvae) swims around then encounter 1st intermediate host (often snail)
  • reproduce and form Redia larvae then Cercaria larvae
  • Cercaria are released and encounter 2nd intermediate host
  • Form Metacercaria - then taken up by definitive host
  • Cycle begins again
26
Q

what do Blood Flukes cause?

A

schistosomiasis

causes necrosis of organs

27
Q

Blood fluke sexes

A

have separate sexes

female lives in groove in males body

pair up for life

28
Q

Blood fluke lifecycle

A
  • Eggs released in faeces or urine into water
  • Miracidium forms (ciliated larvae)
  • Penetrate snail host
  • Cercaria larvae released and burrow into skin using enzymes to break down skin and tail to burrow
  • Make their way through the blood system into bladder or intestine (definitive host)
29
Q

blood Fluke worm genome

A

lots of enzymes for breaking down proteins - can’t make own fats

30
Q

bloodfluke infection - allergies?

A

people who have blood fluke infection have fewer allergies

31
Q

Diplostomum spathaceum parasite (in fish)

A
  • Parasite causes fish to form cataracts
  • When the parasite is ready to be passed on the cataract is at its highest stage
  • Fish with well-developed cataract are easier for birds to catch
  • Birds are the definitive host
32
Q

Lancet fluke

A
  • Lives in bile duct of ruminants
  • Miracidia larvae are passed to particular snail species
  • Cercariae larva are released in slime balls
  • Ants collect slime balls, take to nest and feed on them
  • Cecariae from into metacercaria within ants
  • Causing ants to change their behaviour
  • Ants climb to the top of grass blades and clamp on to where ruminants would eat and wait to get eaten by the final host
  • Does this daily until eaten
33
Q

Co-operative trematodes

A
  • Lots of different larvae from different species / different parents infect a host
  • Division of labour
  • Some are reproductive ones and others are solider
  • Soldier larvae will attack other individuals that aren’t related or from a different species
34
Q

Tapeworms (cestoidea)

A
  • Tegument
  • No gut
  • Scolex - hooked head region that attaches to host intestine
  • Strobila (proglottids, formed in neck region) - packed full of reproductive tissue
  • Have Intermediate host(s)
35
Q

What are platyhelminthes?

A

Flatworms

36
Q

Larval staged within Flukes

A
  • Miracidia
  • Redia
  • Cercaria
  • Metacercaria

Invertebrates (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions