Phylum: Arthropods Arthropods are segmented coelomates with exoskeletons and jointed appendages Arthropods are segmented coelomates with exoskeletons and jointed appendages This phylum is represented in nearly all habitats in the biosphere. This phylum is represented in nearly all habitats in the biosphere. Arthropods are regarded as the most successful animal phylum. Arthropods are regarded as the most successful animal phylum. The diversity التنوع and success والنجتح of arthropods is largely due to three features: The diversity التنوع and success والنجتح of arthropods is largely due to three features: - body segmentation تعقل الجسم, - body segmentation تعقل الجسم, - a hard exoskeleton جليج خارجي صلب, - a hard exoskeleton جليج خارجي صلب, - and jointed appendages زوائد مفصلية. - and jointed appendages زوائد مفصلية. Lecture 17: Animal Classification

The body of an arthropod is completely covered by the cuticle, an exoskeleton constructed from layers of protein and chitin. The body of an arthropod is completely covered by the cuticle, an exoskeleton constructed from layers of protein and chitin. The exoskeleton of arthropods is strong and relatively impermeable to water. The exoskeleton of arthropods is strong and relatively impermeable to water. Arthropods have well-developed sense organs, including eyes for vision, olfactory receptors for smell, and antennae for touch and smell. Arthropods have well-developed sense organs, including eyes for vision, olfactory receptors for smell, and antennae for touch and smell. Arthropods have an open circulatory system in which hemolymph fluid is propelled by a heart through short arteries into sinuses (the hemocoel) surrounding tissues and organs. Arthropods have an open circulatory system in which hemolymph fluid is propelled by a heart through short arteries into sinuses (the hemocoel) surrounding tissues and organs. Arthropods have evolved a variety of specialized organs for gas exchange. Arthropods have evolved a variety of specialized organs for gas exchange. Phylum: Arthropods

chelicerae mandibles فكوكThey have clawlike feeding appendages, chelicerae, crustaceans have jawlike mandibles فكوك. antennae قرون استشعار compoundeyesHave sensory antennae قرون استشعار and usually a pair of compound eyes أعين مركبة in addition to simple eyes. Arthropods have been grouped into the phylum Arthropoda.

1-Class Arachnida طائفة العنكبيات These include scorpions العقارب, spiders العناكب, ticks القراد, and mites الحلم. These include scorpions العقارب, spiders العناكب, ticks القراد, and mites الحلم. Nearly all ticks are blood-sucking ماص للدماء parasites on the body surfaces of most animals. Nearly all ticks are blood-sucking ماص للدماء parasites on the body surfaces of most animals. In most spiders, respiration التنفس is carried out by book lungs الرئة الكتابية. In most spiders, respiration التنفس is carried out by book lungs الرئة الكتابية.

2-class Insecta طائفة الحشرات They live in almost every terrestrial habitat and in fresh water, and flying insects fill the air. They live in almost every terrestrial habitat and in fresh water, and flying insects fill the air. The study of insect, (Entomology) is a vast field with many subspecialties, including physiology, ecology, and taxonomy….etc. The study of insect, (Entomology) is a vast field with many subspecialties, including physiology, ecology, and taxonomy….etc. Class Insecta is divided into about 26 orders. Class Insecta is divided into about 26 orders. Many insects have one or two pairs of wings that emerge from the dorsal side of the thorax. Many insects have one or two pairs of wings that emerge from the dorsal side of the thorax.

The Insects 750,000 + species insects described, but may be 30 million species undescribed. Many adaptations make insects one of the most successful terrestrial animals. Exoskeleton for water conservation Tracheal System for gas exchange Metamorphosis Many types of mouth parts Flight

Fig رأسصدربطن قرون استشعار عين مركبة

Modified mouthparts have allowed insects to diversify and take advantage of many different food sources. Modify generic structures for various food sources. Generalized Insect Mouthparts Specialized Mouthparts

The internal anatomy of an insect includes several complex organ systems. The internal anatomy of an insect includes several complex organ systems. In the complete digestive system, there are regionally specialized organs with discrete functions. In the complete digestive system, there are regionally specialized organs with discrete functions. Metabolic wastes are removed from the hemolymph الدم by Malpighian tubules أنابيب ملبيجي, outpockets of the digestive tract. Metabolic wastes are removed from the hemolymph الدم by Malpighian tubules أنابيب ملبيجي, outpockets of the digestive tract. Respiration is accomplished by a branched, chitin-lined tracheal system الجهاز القصبي that carries O 2 from the spiracles directly to the cells. Respiration is accomplished by a branched, chitin-lined tracheal system الجهاز القصبي that carries O 2 from the spiracles directly to the cells. The insect nervous system consists of a pair of ventral nerve cords حبلين عصبيين بطنيين with several segmental ganglia. The insect nervous system consists of a pair of ventral nerve cords حبلين عصبيين بطنيين with several segmental ganglia.

3 Kinds of Insect Metamorphosis Ametabolous Metamorphosis – only difference between larvae and adult are size; both are wingless. Silverfish, Order Thysanura. After Flight… Hemimetabolous Metamorphosis – develop from egg to adult has several stages (instars) with smaller versions of adults called nymphs. Immature nymphs have no wings or genitalia until adult.

Incomplete or Hemimetabolous Metamorphosis

Holometabolous Metamorphosis – after hatching from egg, immatures are called larvae (very different body form than adult). After several instars, the last larval molt forms a pupa – undergoes radical body form change. Protective case may enclose pupal stage: Moths use silk to make a cocoon. Butterflies use the larval exoskeleton to make a chrysalis. Adult emerges from case very different in body form – eclosion.

Complete or Holometabolous Metamorphosis

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