Practical Notes Flashcards
What are acoelomates?
Animals that have no body cavity. The infernal organs have direct contact with the epithelium. Semi-solid mesodermal tissues between the gut and body wall hold their body together.
What are pseudocoelomate animals?
They have a pseudcoel which means they have a false cavity because It is not made within the mesoderm nor does It end fully enclosed by mesoderm. Also organs in it are not as fully organized as in a real coelomate.
What are eucolomate animals?
They are animals with a true coelom (body cavity). True coeloms may be either fluid or gas filled; they provide protection and support for internal organs as well as more space in which organs can develop . Animals with coeloms have a faster locomotion and larger body size.
Characteristics of a platyhelmithes
Bilaterally symmetrical body usually flattened dorsoventrally
Triploblastic (three tissues)
The gut (if present) has a single opening
There is a definitive head with sense organs and a central nerve system
Excretion by flame-cells
Complete digestive track no anus
Many parasitic.
Characteristics of class Turbellaria
Free-living and primarly carnivorous
Mostly freshwater, few marine and terrestrial
Body is dorso-ventrally flattened
No anus and mouth on ventral side
Locomotion using cilia which are on the ventral side on the epidermis. They Also move by muscular movements.
Characteristics of dugesia
Freshwater
Intestine 3 primary branches
Locomotion vía cilia and secreted mucus from mucus cells in epidermis
LEARNING DIAGRAM
What are some main differences between sponges and dugesia ?
Sponges are asymmetrical and dugesia has a bilateral symmetry.
Sponges have a cellular organisation and dugesia have an organ organisation.
Sponges don’t have any cephalisation and dugesia has a definitive head.
How does dugesia feeds?
It attaches mouth to its prey, releases digestive enzymes, sucks digested tissues and vomits the waste because It doesn’t have an anus.
Characteristics of platyhelmithes
Always parasitic
2 hosts ( at least one vertebrate)
Hermophroditic - individual segments with reproductive system released to environment.
No gut system -absorb nutrients straight across body surface
Attachment to organs
Characteristics of dipellyium sp.
Parasitic tapeworm in dogs
In the development stages their host its an invertebrate
Consists on a head called scolex, a neck and a series of segments called proglottids (new proglottids produced on head region )
Mature proglottids contain male and female reproductive organs.
Sperm from a tapeworm will fertilise the egg of the same or another tapeworm.
The mature proglottids will burst open to release the zygotes which are released in the feaces of the host which then are consumed by a new host and the cycle continues.
LEARN THE DIAGRAM of SCOLEX
How dipyllidium caninum feeds?
They are normally attached to the intestines and they absorb the nutrients that arrive from the stomach.
Why the scolex of the Dipyllidium not considered a true head?
Doesn’t have the organs that characterize a head.
How does a mature proglottids looks like?
Examine diagram in practical
Compare dugesia and dipyllidium
Dugesia definitive head- dipyllidium scolex
Dugesia and dipyllidium both hermaphrodites
Digestive system present on dugesia and not in dipyllidium
Characteristics of trematoda
Parasitic
Highly complex life cycles
Blind gut
Sporocyst within snail host
Characteristics of fasciola hepiteca
Parasite that infects many species of animals.
Largest flukes - 3.5 by 1.5cm
Live in liver or bile duct
Found in 46 sp
Intermediate host - Lymnea snail
In adult stage they have a large leaf-shaped body
Examine DIAGRAM
Characteristics of phylum nematoda
Triploblastic
Have a pseudocoelem
Bilaterally symmetrical
Complete digestive track with two openings ( mouth and anus)
Thick cuticle and under it longitudinal muscles
Lack circular muscle and their muscle is limited ti a thrashing motion
Mostly dioceious
How cam you differentiatte males from females nematodes?
Their reproductive features
The openings they have
The bigger one is a female
And the shape
Locomotion of nematodes
They move in an S form one part of their body contracts while the other relaxes pushing It forward
An example of an Aecoelomate?
Fasciola hepatica :look at DIAGRAM
The mesoderm takes up more space in acoelomates
An example of pseudocoelomates?
Ascaris sp : look at DIAGRAM
In the pseudocoelomates the mesoderm doesn’t occupy as much space as in acoelomates because as pseudocoelomates need to process more food therefore they have a larger intestines track and less mesoderm .
Main characteristics of Phylum mollusca
They have a reduced coelem Dorsal visceral mass Mantle A broad ventral foot Have a radula to feed And a shell for protection
Mollusca foot in the different classes of molluscs
Gastropoda: its located in its ventral part and It is large and flat.
Polyplachora: It is located in its ventral part and It is large , flat and strong.
Bivalvia: In the center and use for digginng ( bigger the foot= more movement)
Chephalopoda: located in the anterior part and It is modified Intro tentacles use to grab food.
The molluscan mantle
Gastropoda: located dorsal part under the shell, It can wrap around shell.
Polyplacophora: runs down both sides in the ventral cavity and secreted plates and houses gills.
Bivalvia: inside and besides the shell, secretes valves(shell) , home for zooxanthallae.
Cephalopoda: located in the dorsal part, outside shell and cover shell, mantle cavity used for locomotion in water
What are some functions of the molluscan mantle ?
Create the shell
Rap organs
Carry respiratory organs
Molluscan shell
Gastropoda: dorsal and one side thin while the other is thick.
Polyplacophora: dorsal and It has 8 valves.
Bivalvia: 2 shells hinged
Cephalopoda: dorsal and inside the body, large chambered shell, reduced in octopuses
How is an gastropod shell?
Look at DIAGRAM .
How is a shell in bivalves?
Look at the DIAGRAM
What are Molluscan radula ?
Rasp-like belt positioned over a tongue-like structure with rows of teeth.
Characteristics of bivalves
Second largest class of mollucs Lack a head and a radula