Select a letter to uncover fascinating creatures starting with it today. Here you can find out all about thousands of mammals, reptiles, birds, amphibians, and fishes walking, flying, and swimming the Earth. Marsupials are mammals that give birth to small, relatively undeveloped young, known as ‘joeys’.
Birds
The presence of muscles and mobility is one of the primary characteristics of the animal kingdom. Animals that are considered mammals include warm-blooded vertebrates that have hair or fur and whose babies drink milk. Unlike other animal types like birds and insects, all mammal babies drink milk that comes from their mother’s bodies.
Development
- Although they don’t have a backbone – and are therefore not vertebrates – they do possess a flexible central nerve cord called a notochord.
- Our comprehensive animal database serves educators, researchers, students, and nature lovers across educational institutions, wildlife organizations, and conservation groups globally.
- So integral is movement to the conception of animals that sponges, which lack muscle tissues, were long considered to be plants.
Like mammals, birds are warm-blooded vertebrates with four-chambered hearts. However, they are more closely related to reptiles and are believed to have evolved from dinosaurs. Historically, Aristotle divided animals into those with blood and those without.
Animal Diversity Web
Animal Pedia is a leading online website offering a vast library of information on animals from all corners of the globe. Discover our newest additions to the animal kingdom database. Then test your knowledge with our fun, free Animal Quizzes! You can also download free coloring pages, word searches, and animal mazes on our Activity Sheets page.
- The most prolific and easily recognizable members of the invertebrate family are insects.
- The presence of muscles and mobility is one of the primary characteristics of the animal kingdom.
- Here you can find out all about thousands of mammals, reptiles, birds, amphibians, and fishes walking, flying, and swimming the Earth.
- Although, like sponges, sea squirts look more like plants than animals, they have organs and a simple nervous system.
- Carl Linnaeus created the first hierarchical biological classification for animals in 1758 with his Systema Naturae, which Jean-Baptiste Lamarck expanded into 14 phyla by 1809.
Animal Classification
Common to all living animals, 6,331 groups of genes have been identified that may have arisen from a single common ancestor that lived about 650 Mya during the Cryogenian period. Most people know that crabs are crustaceans, but the group contains many other types of animals, including lobsters, shrimps, krill and water fleas. Most crustaceans live in the sea, but some, such as woodlice, are adapted to living on land. In size animals are outdone on land by plants, among whose foliage they may often hide.
In animal classification, each animal is grouped based on various features, such as physical characteristics, genetic relationships, and evolutionary history. Animal classification provides a structured way to name, rank, and classify the millions of animal species discovered. Although all animals share the above characteristics, animals exhibit diverse body plans, life cycles, and forms of behavior. The kingdom Animalia is one of the most diverse groups of organisms on the planet, containing millions of species spread across various habitats around the globe. To have the classification of an amphibian, an animal must be a vertebrate, require water to survive, be cold-blooded, and spend time both on land and in water.
More than half are passerines, or “perching birds”, members of the order Passeriformes. Passerine feet have three forward-facing toes and one backward-facing toe, an arrangement favorable to perching. Most mollusks live in the sea, but some, such as snails and slugs, are also found on land. In order to be placed in the animal kingdom, rather than another kingdom, an organism animal spirits must have certain characteristics, which are listed in the following section.
Joeys undergo further development within a special pouch in the mother’s body. The majority of the world’s marsupials are found in Australia (including New Guinea and nearby islands); the rest are found in the Americas. Last but not least we come to the mammals, members of the class Mammalia. Mammals have hair, are warm-blooded, breathe air, and all but five species give birth to live young. Amphibians have moist skin, and lack the protective scales found in reptiles.
One of the most distinctive characteristics of mammalia is that female mammals have mammary glands. This ready-made source of nourishment is highly advantageous to infant mammals. Birds are the only living descendants of dinosaurs, and are often referred to as “avian dinosaurs”.
Although, like sponges, sea squirts look more like plants than animals, they have organs and a simple nervous system. Sponges are very primitive animals, lacking organs and a nervous system. (A nervous system consists of nerves that transmit signals between different parts of the body, allowing them to ‘talk’ to each other.) Unlike other animals, the bodies of sponges are not symmetrical.
Animal classification not only provides a standardized nomenclature for scientists to communicate about different species, but it also reveals evolutionary relationships among various animal groups. The definition of an invertebrate is any animal that does not have a backbone or vertebral column. The most prolific and easily recognizable members of the invertebrate family are insects. It’s estimated that upwards of 30 million individual species of invertebrates may exist accounting for between percent of all organisms on the planet.
