Transcript المحاضرة السادسة عشر Sixteenth lecture

Lecture 15: Kingdom: Animalia
INVERTEBRATES
)‫الالفقريات (ليس لها عمود فِقَري‬
4- Phylum: Nematoda (Round worm)
Example: Ascaris sp.
 Roundworms are found in most
aquatic habitats, wet soil, moist
tissues of plants, and the body fluids
and tissues of animals.
 Some species parasitize animals.
 They range in length from less than 1
mm to more than a meter.
 The body of Nematode is covered
with a tough exoskeleton, the cuticle.
 They have a complete digestive tract
‫قناة هضمية كاملة‬.
 Nematodes usually engage in sexual
reproduction ‫التكاثر الجنسي‬
5- Phylum: Annelida (Segmented worms)
Class: Oligochaeta ‫قليلة األشواك‬
Example: Earthworms ‫ديدان األرض‬
 All annelids (“little rings”) have segmented bodies.
 Annelids live in the sea, most freshwater habitats, and wet soil.
 The coelom of the earthworm is partitioned by septa ‫بفواصل‬,
but the digestive tract, longitudinal blood vessels, and nerve
cords penetrate the septa and run the animal’s length.
 Most annelids, including earthworms, burrow in sand and silt.
Earthworms:
 The digestive system consists of a pharynx ‫بلعوم‬, an esophagus
‫مرئ‬, crop ‫حوصلة‬, gizzard ‫قانصة‬, and intestine ‫أمعاء‬.
 The closed circulatory system carries blood with oxygen-
carrying hemoglobin through dorsal and ventral vessels
connected by segmental vessels.
 In each segment is a pair of excretory tubes, metanephridia, ‫كلية‬
‫ بدائية‬that remove wastes from the blood and coelomic fluid.
 Earthworms are cross-fertilizing hermaphrodites.
 Some
earthworms
can
also
reproduce
fragmentation ‫ بالتقطيع‬followed by regeneration.
asexually
by
Earthworm
6- Phylum: Mollusca
• Mollusca includes snails ‫ القواقع‬and slugs ‫البزاقات‬, octopus
‫ األخطبوط‬and squid ‫الحبار‬.
• Most mollusks are marine, some inhabit fresh water, and some
snails and slugs live on land.
• Mollusks are soft-bodied animals, but most are protected by a
hard shell ‫ صدفة قوية‬of calcium carbonate.
• All mollusks have a muscular foot for locomotion, and a
mantle ‫البُرنّس‬.
• Most mollusks have separate sexes, with gonads, and some are
hermaphrodites.
1- Class: Gastropoda ‫البطنقدميات‬
e.g. snails )‫الحلزون (القوقع األرضي‬
 Most Gastropoda are marine, but there are also many freshwater
species.
 The anus and mantle cavity are above the head in adults.
 Most gastropods are protected by a spiraled shell ‫صدفة حلزونية‬.
 Other species have lost their shells entirely and may have
chemical defenses against predators.
 Many gastropods have distinct heads with eyes at the tips of
tentacles.
 They move by their foot.
2- Class: Cephalopoda
e.g. Octopus ‫األخطبوط‬
‫الرأسقدميات‬
• Cephalopods use rapid movements toward their prey which they capture
with several long tentacles.
• A mantle covers the visceral mass, but the shell is reduced and internal in
squids ‫الحبار‬, missing in many octopuses.
 Most octopuses live on the
seafloor ‫قاع البحر‬.
 Cephalopods
have
an
active, predator ‫مفترسات‬.
 They have a well-developed
nervous system
with
a
complex brain and welldeveloped sense organs.