How to use animal in a sentence Although humans might have hunted at the lake, the researchers found no stone tools or animal bones bearing butchery marks. Sony built a tiny mirrorless camera with a full-frame sensor inside Stan Horaczek September 16, Popular-Science. Ancient Lystrosaurus tusks may show the oldest signs of a hibernation-like state Susan Milius September 16, Science News. The Red Year Louis Tracy. Children's Ways James Sully. Our Little Korean Cousin H.
Lee M. Australian informal a very dirty car. A multicellular organism with membranous cell walls of the kingdom Animalia, differing from plants in certain typical characteristics such as capacity for locomotion, nonphotosynthetic metabolism, pronounced response to stimuli, restricted growth, and fixed bodily structure.
An animal organism other than a human, especially a mammal. A human considered with respect to his or her physical, as opposed to spiritual, nature.
Relating to, characteristic of, or derived from an animal or animals. Relating to the physical as distinct from the spiritual nature of humans. Published by Houghton Mifflin Company. Any of the multicellular organisms belonging to the kingdom Animalia. Thus, land animals in due course evolved internal gas exchange systems, waterproof external layers, skeletal systems endo- or exoskeletons , and a form of reproduction that does not involve water.
On land, the appearance of primitive plants, trees, and shrub-like forests provided new habitats for arthropods. The first tetrapods to appear were amphibians e. The land continued to be dominated by arthropods, such as arachnids and wingless insects. However, another major mass extinction occurred.
Arthropods on land continued to evolve. Some of them grew into giants. For example, the millipede-like Arthropleura is regarded as the largest land invertebrate as it could grow to size up to 8. The dragonfly-like insect Meganeura , in turn, is the largest flying insect.
One of the most important evolutionary milestones was the appearance of tetrapods that lay amniotic eggs. The laying of amniotic eggs in a drier environment allowed tetrapod ancestors of reptiles, birds, and mammals to move farther away from the waterside, and thereby dominate farther inland. Because of this, amniotes diversified greatly by the end of this period. In , Carl Linnaeus created a biological classification system for animals.
In , Ernst Haeckel proposed to divide the animal kingdoms into two groups: the multicellular Metazoa and the single-celled Protozoa. Later, the protozoans are no longer considered animals and have been designated with their own biological kingdom. At present, the kingdom Animalia is comprised of the following extant phyla:.
Do you want to know what makes the chordates different from the rest of the animal groups? The answers are in this Forum: What is phylum chordata? Come join us to discover more! Animals have long been a key player in the ecosystem and performing an essential role in the lives of other organisms whether from the same kingdom or not.
For instance, the carbon dioxide that the animals breathe out is essential to plants and other autotrophs as it is a reactant in the early steps of photosynthesis. Animals have also a great impact on the lives of humans. Besides as a source of meat, milk, and eggs, animals are also a source of materials e. Because of this, some of them have been domesticated. Cows, chickens, horses, pigs, sheep, etc. There are also animals that are made as pets, e.
Certain animals e. Trivia: All vertebrates are chordates but not all chordates are vertebrates! Read more here: What is phylum chordata? Join us for more amazing biology facts! The branch of science that deals with animals is zoology. The topics are varied. Some of the areas of study are morphoanatomy, histology , physiology , ecology, evolution , taxonomy , and ethology.
Specific groups of animals being studied also led to sub-disciplines such as entomology the study of insects , herpetology the study of amphibians and reptiles , ornithology the study of birds , mammalogy the study of mammals , etc.
Try to answer the quiz below to check what you have learned so far about animals. Plant cells have plastids essential in photosynthesis. They also have an additional layer called cell wall on their cell exterior. Although animal cells lack these cell structures, both of them have nucleus, mitochondria, endoplasmic reticulum, etc. Read this tutorial to learn plant cell structures and their roles in plants Read More.
A running water environment offers numerous microhabitats for many types of animals. Similar to plants, animals in lotic communities have acquired evolutionary adaptations to better suit this running water environment.
Know more about their evolutionary adaptations in this tutorial Life, as we know it today, is presumed to have started in the sea and many of them were likely eukaryotic animal-like organisms. Because of the expanding diversity of animal life forms, taxonomists eventually came up with a classification scheme to group them into various phyla.
Know more about the early animals that were likely the first ones to roam the ancient seas through this tutorial Animals living in aquatic habitats have diversified and evolved through time. These example sentences are selected automatically from various online news sources to reflect current usage of the word 'animal. Send us feedback. Latin, from animale , neuter of animalis animate, from anima soul — more at animate.
See more words from the same century. Accessed 11 Nov. More Definitions for animal. Nglish: Translation of animal for Spanish Speakers.
Britannica English: Translation of animal for Arabic Speakers. Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free! Log in Sign Up. Save Word. Essential Meaning of animal.
Dogs, like humans, are social animals. You're all behaving like a bunch of animals. Full Definition of animal Entry 1 of 2. Definition of animal Entry 2 of 2.
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