THE UNIVERSITY OF DODOMA QN 11; Attempt classification of marsupial and placental mammals to order level (order rodentia)

INTRODUCTION Rodents is the Latin word rodere meaning to gnaw Rodents are small terrestrial mammals, specialized for gnawing (to bite) and with a high rate of reproduction. Their origin has remained almost as elusive. The first appearance in the fossil records in the latest Paleocene shortly after extinction of non- avian dinosaurs.

CLASSIFICATION OF ORDER RODENTIA The order is divided into five suborders as described below; Animalia chordata mammalia rodentia Suborder Anomaluromorpha example Tailed squirrel Suborder Castorimorpha example kangaroo rats Suborder Hystricomorpha example guinea pigs Suborder Myomorpha example jumping mice Suborder Sciuromorpha example dormice

FEATURES OF ORDER RODENTIA DISTINCTIVE FEATURES OF RODENTS. single pair of continuously growing, razor-shaped incisors. There is a gap (diastema) between the incisors and the cheek teeth in most species due to absence of canines. rodents practice coprophagy (eating their own faecal pellets) so as to improve the absorption of large quantities of the essential nutrients. Mating among rodents can vary from monogamy, polygyny, to promiscuity (no choice just mix). In many species, the penis contains a bone called the baculum

HABITAT, ECOLOGY AND ADAPTATION OF ORDER RODENTIA They are the only terrestrial placental mammals that have colonized Australia and New Guinea without human intervention. Adapted to almost every terrestrial habitat from cold tundra (where they can live under snow) to hot deserts. Ecological roles, some rodents are considered keystone species and ecosystem engineers in their respective habitats. The burrowing activities play important roles in soil aeration and nutrient redistribution, Also burrowing rodents may eat fungi and spread spores through their feces, thereby allowing the fungi to disperse and form symbiotic relationships with the roots of plants,

ANATOMY OF RODENT’S TEETH They have two pairs of incisors one from each jaw which grows continuously. Rodents don’t have canines like many other mammals. Teeth Functions; cutting through wood , biting through the skin of fruit, prey capture or defense.

FOOD HABITS REPRODUCTION Most of rodents are herbivores, Some rodents, like the house mouse, are omnivores (eating plants and animals). REPRODUCTION Rodents reproduce by internal fertilization For example, the guinea pig has a gestation period of 68 days. Its young are born fully haired, have developed teeth, eyes open, and can eat solid food. Rodents have a high rate of reproduction.

LOCOMOTION Some use Bipedal as the means of moving by two limbs it used by kangaroo rats and mice. Hopping mice-jeroas and kangaroo mice have very long tails, usually with a tuft of hair at the end to help with balancing. European harvest mouses, their tail are truly prehensile and functions as a fifth limb. DIGESTION Rodents have large caecum and appendix which shelters bacteria which produces enzymes for digestion of cellulose. Food materials are chewed in the mouth, swallowed and broken down by cellulase produced by bacteria.

CONT…digestion system of rodent

IMPORTANCE OF RODENTS DISADVANTAGES OF RODENTS A source of food. In religious ceremonies China and Europe, guinea pigs have been used in indigenous religious activities since the 1960s. In research studies. In biological experiments. DISADVANTAGES OF RODENTS Destruction of human properties e.g. crops, roof of houses and destruction of clothes Causes diseases e.g.. plaque

CONCLUSION Rodentia, is the most diversified order of class mammalia and have been more useful in various ways by human being . Also, some species are more dangerous in destruction of human properties and causing diseases hence bring more human attention in killing them, these reduce the rodents to the extent that affect the ecosystem. Human being must pay attention in conserving rodents and manage their harmful effects.

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