Grasshoppers have antennae that are generally shorter than their body and short ovipositors. They also have pinchers or mandibles that cut and tear off food. Those species that make easily heard noises usually do so by rubbing the hind femurs against the forewings or abdomen (stridulation), or by snapping the wings in flight. Tympana, if present, are on the sides of the first abdominal segment. The hind femora are typically long and strong, fitted for leaping. Generally they are winged, but hind wings are membranous while front wings (tegmina) are coriaceous and not fit for flight. Females are normally larger than males, with short ovipositors. Males have a single unpaired plate at the end of the abdomen. Females have two pairs of valves (triangles) at the end of the abdomen used to dig in sand during egg laying.
They are easily confused with the other sub-order of Orthoptera, Ensifera (crickets), but are different in many aspects, such as the number of segments in their antennae and structure of the ovipositor, as well as the location of the tympana and modes of sound production. Ensiferans have antennae with at least 20-24 segments, and caeliferans have fewer. In evolutionary terms, the split between the Caelifera and the Ensifera is no more recent than the Permo-Triassic boundary (Zeuner 1939).
Recent estimates (Kevan 1982; Günther, 1980, 1992; Otte 1994-1995; subsequent literature) indicate some 2,400 valid Caeliferan genera and about 11,000 valid species described to date. Many undescribed species exist, especially in tropical wet forests. The Caelifera are predominantly tropical
Grasshoppers prefer to eat grasses, leaves and cereal crops, but many grasshoppers are omnivorous. The majority of grasshoppers arepolyphagous. Many will eat from multiple host plants in one day, while some prefer to rely on the same host plant. Only one of the 8000 species of grasshopper is monophagous and will only eat a single species of plant.
The digestive system of insects includes a foregut (stomodaeum, the mouth region), a midgut(mesenteron), and a hindgut (proctodaeum, the anal region). The mouth is distinct due to the presence of a mandible and salivary glands. The mandible can chew food very slightly and start mechanical digestion. Salivary glands (occur in buccal cavity) chemically digest the carbohydrates in the grasses and similar foods they eat. The buccal cavity continues with pharynx, esophagus and crop. The crop has the ability to hold food. From the crop, food enters the gizzard, which has tooth-like features in it. From there, food enters the stomach. In the stomach, digestive enzymes mix with the food to break it down. These enzymes originate from the gastric caeca surrounding the stomach. This leads to the malpighian tubules. These are the chief excretion organs. The hindgut includes intestine parts (including the ileum and rectum), and exits through the anus. Most food is handled in the midgut, but some food residue as well as waste products from the malpighian tubules are managed in the hindgut. These waste products consist mainly of uric acid, urea andamino acids, and are normally converted into dry pellets before being disposed.
The salivary glands and midgut secrete digestive enzymes. The midgut secretes protease, lipase, amylase, and invertase, among other enzymes. The particular ones secreted vary with the different diets of grasshopper
An earthworm is a tube-shaped, segmented animal commonly found living in soil, that feeds on live and dead organic matter. Its digestive system runs through the length of its body. It conducts respiration through its skin. An earthworm has a double transport system composed of coelomic fluid that moves within the fluid-filled coelom and a simple, closed blood circulatory system. It has a central and a peripheral nervous system. The central nervous system consists of two ganglia above the mouth, one on either side, connected to a nerve cord running back along its length to motor neurons and sensory cells in each segment. Large numbers of chemoreceptors are concentrated near its mouth. Circumferential and longitudinal muscles on the periphery of each segment enable the worm to move. Similar sets of muscles line the gut, and their actions move the digesting food toward the worm's anus.
Earthworms are hermaphrodites—each individual carries both male and female sex organs. As an invertebrate, it lacks a skeleton, but it maintains its structure with fluid-filled coelom chambers that function as a hydrostatic skeleton.
"Earthworm" is the common name for the largest members of Oligochaeta (which is either a class or a subclass depending on the author) in the phylum Annelida. In classical systems, they were placed in the order Opisthopora, on the basis of the male pores opening posterior to the female pores, though the internal male segments are anterior to the female. Theoretical cladistic studies have placed them, instead, in the suborder Lumbricina of the order Haplotaxida, but this may again soon change. Folk names for the earthworm include "dew-worm", "rainworm", "night crawler", and "angleworm" (due to its use as fishing bait).
Larger terrestrial earthworms are also called megadriles (or big worms), as opposed to the microdriles (or small worms) in the semiaquatic familiesTubificidae, Lumbriculidae, and Enchytraeidae, among others. The megadriles are characterized by having a distinct clitellum (which is more extensive than that of microdriles) and a vascular system with true capillaries.
Earthworms are far less abundant in disturbed environments and are typically active only if water is present.
Millipedes (class Diplopoda) are myriapodous arthropods that have two pairs of legs on most body segments. Each double-legged segment is a result of two single segments fused together as one (the name "Diplopoda" comes from the Greek words διπλοῦς (diplous), "double" and ποδός (podos), "foot"). Most millipedes have very elongated cylindrical or flattened bodies with more than 20 segments, while pill millipedes are shorter and can roll into a ball, like a pillbug.
The name "millipede" is a compound word formed from the Latin roots mille ("thousand") and pes ("foot"). Despite their name, no known millipede has 1,000 legs, although the rare species Illacme plenipes has up to 750. Common species have between 36 and 400 legs. There are approximately 12,000 named species in ca. 140 families. The longest species is the giant African millipede (Archispirostreptus gigas).
Most millipedes are slow-moving detritivores, eating decaying leaves and other dead plant matter. However, they can also be minor garden pests, especially in greenhouses where they can cause severe damage to emergent seedlings.
Millipedes can be easily distinguished from the somewhat similar and related centipedes (Class Chilopoda) which move rapidly, are carnivorous, and have a single pair of legs for each body segment. The scientific study of millipedes is known as diplopodology, and a scientist who studies them is called a diplopodologist.
This class of arthropod is thought to be among the first animals to have colonised land during the Silurian geologic period. These early forms probably ate mosses and primitive vascular plants. The oldest known land creature, Pneumodesmus newmani, was a 1 cm (0.39 in) long millipede, and lived 428 million years ago. In the Upper Carboniferous (340 to 280 million years ago),Arthropleura became the largest known land invertebrate of all time, reaching lengths of up to 2.6 m (8 ft 6 in). Millipedes, centipedes, and other terrestrial arthropods attained very large sizes in comparison to modern species in the oxygen-rich environments of the Devonian and Carboniferous periods, and some could grow larger than one metre. As oxygen levels lowered through time, arthropods became smaller in size.
Millipedes range from 2 mm (0.079 in) to around 35 cm (14 in) in length, and can have as few as eleven to over one hundred segments. They are generally black or brown in colour, although there are a few brightly coloured species.
The millipede's most obvious feature is its large number of legs. Having many short legs makes millipedes rather slow, but the many legs pushing in unison provides powerful strength for burrowing.