Arachnids
Athropods: Arachnids
Brief Intro to Arachnids:
-Arachnids are a class (Arachnida) of joint-legged invertebrate animals under the Arthropods classification.
-Almost all extant arachnids are terrestrial. However, some inhabit freshwater environments and, with the exception of the pelagic zone, marine environments as well. They comprise over 100,000 named species, including spiders, scorpions, harvestmen, ticks, mites and Solifugae.
(Any water in a sea or lake that is neither close to the bottom nor near the shore can be said to be in the pelagic zone.)
Anatomy:
1: Almost every adult arachnids have 4 pairs of legs
-The first pair of legs, the chelicerae are adapted for feeding, defense and combat situations.
-The second pair, the pedipalps have been adapted for feeding, locomotion and reproductive functions.
2: This part is called the cephalothorax
3: This part is called the Abdomen
Dietary:
-Arachnids are mostly carnivorous, feeding on the pre-digested bodies of insects and other small animals.
-Arachnids eat their prey by pouring digestive juices produced in their stomachs over their prey after killing it with their pedipalps and chelicerae. The digestive juices then rapidly turn the prey into a broth of nutrients which the arachnid sucks.
Arachnids have two kinds of eyes, the lateral and median ocelli. The lateral ocelli evolved from compound eyes and may have a tapetum, which enhances the ability to collect light. With the exception of scorpions, which can have up to five pairs of lateral ocelli, there are never more than three pairs present. The median ocelli develop from a transverse fold of the ectoderm. The ancestors of modern arachnids probably had both types, but modern ones often lack one type or the other. The cornea of the eye also acts as a lens, and is continuous with the cuticle of the body. Beneath this is a transparent vitreous body, and then the retina and, if present, the tapetum. In most arachnids, the retina probably
Brief Intro to Arachnids:
-Arachnids are a class (Arachnida) of joint-legged invertebrate animals under the Arthropods classification.
-Almost all extant arachnids are terrestrial. However, some inhabit freshwater environments and, with the exception of the pelagic zone, marine environments as well. They comprise over 100,000 named species, including spiders, scorpions, harvestmen, ticks, mites and Solifugae.
(Any water in a sea or lake that is neither close to the bottom nor near the shore can be said to be in the pelagic zone.)
Anatomy:
1: Almost every adult arachnids have 4 pairs of legs
-The first pair of legs, the chelicerae are adapted for feeding, defense and combat situations.
-The second pair, the pedipalps have been adapted for feeding, locomotion and reproductive functions.
2: This part is called the cephalothorax
3: This part is called the Abdomen
Dietary:
-Arachnids are mostly carnivorous, feeding on the pre-digested bodies of insects and other small animals.
-Arachnids eat their prey by pouring digestive juices produced in their stomachs over their prey after killing it with their pedipalps and chelicerae. The digestive juices then rapidly turn the prey into a broth of nutrients which the arachnid sucks.
Arachnids have two kinds of eyes, the lateral and median ocelli. The lateral ocelli evolved from compound eyes and may have a tapetum, which enhances the ability to collect light. With the exception of scorpions, which can have up to five pairs of lateral ocelli, there are never more than three pairs present. The median ocelli develop from a transverse fold of the ectoderm. The ancestors of modern arachnids probably had both types, but modern ones often lack one type or the other. The cornea of the eye also acts as a lens, and is continuous with the cuticle of the body. Beneath this is a transparent vitreous body, and then the retina and, if present, the tapetum. In most arachnids, the retina probably