Practical Lab 3 Flashcards
Kingdom Animalia - Invertebrates
what are the 3 GERM LAYERS
ectoderm, endoderm, mesoderm
what is the purpose of the ECTODERM
- covers surface of the embryo
- provides an outer covering for animals
- provides covering of the nervous system (IN SOME PHYLA)
what is the purpose of the ENDODERM
- innermost germ layer; lines the gut and digestive tract
- lines the liver and lung cavity
what is the purpose of the MESODERM
- located between the ENDO- & ECTO- derm; forms the muscles and other organs
describe the ACOELOMATE body plan
- as seen in flat worms [Phylum PLATYHELMINTHES]
- it lacks a cavity between the digestive tract and the outer body wall
- the space is filled with MESODERMAL CELLS called PARENCHYMA
describe the PSEUODOELOMATE body plan
- as seen in roundworms [phylum NEMATODA]
- it has a cavity between the digestive tract and outer body wall, filled with liquid called the PSEUDOCOELOM where interal organs are found free
- it is not totally lined with mesodermal cells (but there is a layer under the outer body wall)
what is the PSEUDOCOELOM
it is the liquid filled cavity located between the digestive tract and outer body wall in animals with the PSEUDOELOMATE body plan
explain what the “tube-within-a-tube” body plan is
[refering to pseudoelomate animals] it is when internal organs are found free [within the pseudocoelom]
describe the COELOMATE body plan
- as seen in PHYLUM ANNELIDA, ANTHROPODA, CHORDATA, CNIDARIA;
- the body cavity [COELOM] is totally lined by MESODERM
- the outer body wall and area around interal organs have a layer of mesoderm; these layers connect [dorsally and ventrally] to form MESENTERIES that support the internal organs in the coelom
what is a COELOM
it is the body cavity of coelomates
what is the purpose of the two layers of mesoderm in coelomates
to support/suspend the internal organs in the coelem
what is the purpose of the body cavity
- its fluids protect organs from injury by providing cushioning
- to allow movement of organs independent of the outer body wall
PHYLUM NEMATODA is also referred to as?
roundworms
describe members of PHYLUM NEMATODA
they have long, cylinder-like bodies, with some members found free-living in soil and others existing as parasites
describe two morphological advances of PHYLUM NEMATODA – roundworms (over PHYLUM PLATYHELMINTHES – flatworms)
- they have a pseudocoelom (the fluid filled cavity between the digestive tract and outer body wall)
- they have a complete digestive tract (with mouth and anus)
describe the ASCARIS LUMBRICOIDES – PHYLUM NEMATODA
it is a large, parasitic nematode
describe the male ASCARIS LUMBRICOIDES – PHYLUM NEMATODA
- it is thinner and smaller compared to the female
- AT THE POSTERIOR [4] , it has an anus (for excretion and reporuction), and hooked tail (copulatory spicule; to hold the female’s genital open), cloaca (for collecting feces from the intestine and spermatazoa), seminal vesicle (connects the cloaca and intestine)
- AT THE ANTERIOR END, it has a mouth with three tissue lobes/lips
- has seminal vesicle with thick tubes (the sperm ducts/vas deferens) and thin tubes (the testes (where sperm is produced))
what is unique about nematode sperm?
the sperm is amoeboid, not flagelleted
describe the female ASCARIS LUMBRICOIDES – PHYLUM NEMATODA
- it is larger and longer than male
- AT THE POSTERIOR , it has an anus (for excretion, and straight tail
- AT THE ANTERIOR END, it has a mouth with three tissue lobes/lips; genital pore (opening connected to a short vagina)
- has a vagina which divides the uterus (where fertilizartion occurs) into two.
- the uteri have A THIN OVIDUCT, THREAD-LIKE OVARIES (where eggs are produced by meiosis)
what does DIOECIOUS mean?
an invertebrate having two separate sexes
describe feeding in nematoda
feeding is influenced by the habitat so it may exhibit carnivorous, herbivorous, or parasitic feeding
describe digestion in PHYLUM NEMATODA
- the mouth opens into the muscular pharnyx which pumps food into the thin, flattened, ‘ribbon-like’ intestine which extends to the anus.
- digestive enzymes are produced in the intestine, which is lined by epithelial cells
-digestion begins extracellularly in the intestinal lumen and ends intracellularly
do PHYLUM NEMATODA MEMBERS have a respiratory and circulatory system?
No! but the obtain oxygen from their environment (which is either in moist, interstitial spaces, or by diffusion in the free-living nematodes)
describe reproduction in female nematoda (female ASCARIS)
-A GENITAL PORE is connected to the SHORT VAGINA.
-The vagina divides into TWO UTERI with each segment having a THIN OVIDUCT and THREAD LIKE OVARIES
-Eggs are produced by MEIOSIS in the ovaris
- Fertilization occurs in the uterus
describe reproduction in male nematoda (male ASCARIS)
- The COPULATORY SPICULE is seen at the edge of the ANUS, which the CLOACA is connected to on the outside.
-the cloaca collects feaces and sperm from the SEMINAL VESICLE which has two tubes (THE SPERM DUCT/VAS DEFERNS; serves as transport tube for mature sperm and the TESTES; where sperm is produced).
-during COPULATION sperm enters the cloaca before being deposited into the female
-Nematode sperm are aboeboid not flagellated
describe phylum ANNELIDA (earthworms and clamworms)
-they are worms with distincitive segments or rings called METAMERISM.
-also called SEGMENTED WORMS
-has internal rings which show division of the body by repeated SEPTA (WALLS)
-it has 4 FOUR classes: O.P.A.H. (oligochaeta, Polychaeta, Archiannelida, Hirudinea)
what does ANNULLUS mean
little ring (in Latin)
what evolutionary advances do ANNELIDS have over NEMATODES
- they have a true coelom
-they have a PERITONEUM (layer of mesodermal epithelium in the coelom)
-they have a CNS
-they have a CLOSED circuatory system
-they have SETAE small brsitle-like appendages
what is the SETAE
small bristle-like appendages in ANNELIDS (earthworms)
what is the PERITONEUM
it is the layer of mesodermal epithelium in the coelom in ANNELIDS
