Animal

An Animal is a living organism that belongs to the kingdom Animalia and is characterized by being multicellular, eukaryotic, and heterotrophic, having descended from one or more (unknown) multicellular eukaryote species that lived during the Precambrian.

• AKA: Metazoan, Fauna, Kingdom Animalia.
• Context:
  • It can typically possess Cellular Structure with animal cell membranes lacking animal cell walls.
  • It can typically demonstrate Heterotrophic Nutrition requiring animal food consumption for animal energy acquisition.
  • It can typically exhibit Motility through animal movement mechanisms during some animal life stage.
  • It can typically feature Multicellularity with animal specialized tissues and animal organ systems.
  • It can typically display Embryonic Development with animal blastula formation and animal tissue differentiation.
  • It can typically contain Genetic Material in the form of animal DNA organized into animal chromosomes within an animal cell nucleus.
  • ...
  • It can often show Taxonomic Diversity across numerous animal phyla and animal classes.
  • It can often utilize Sensory Systems for detecting animal environmental stimuli and coordinating animal response.
  • It can often possess Reproductive Capability through animal sexual reproduction or animal asexual reproduction.
  • It can often develop Nervous System structures for animal stimulus processing and animal response coordination.
  • It can often display Homeostatic Regulation of animal internal environment through animal physiological processes.
  • ...
  • It can range from being a Simple Animal to being a Complex Animal, depending on its animal morphological complexity.
  • It can range from being a Microscopic Animal to being a Massive Animal, depending on its animal body size.
  • It can range from being an Aquatic Animal to being a Terrestrial Animal, depending on its animal habitat adaptation.
  • It can range from being a Solitary Animal to being a Social Animal, depending on its animal behavioral pattern.
  • ...
  • It can interact with Environmental Factors through animal adaptation mechanisms and animal evolutionary responses.
  • It can occupy Ecological Niches as animal primary consumers, animal secondary consumers, or animal decomposers.
  • It can participate in Evolutionary Processes through animal natural selection, animal genetic drift, and animal speciation.
  • ...
• Examples:
  • Animal Taxonomic Groups, such as:
    • Porifera (sponges), such as:
      • Bath Sponge demonstrating animal filter feeding without animal true tissue.
      • Glass Sponge featuring animal siliceous spicules.
    • Cnidaria, such as:
      • Jellyfish utilizing animal nematocysts for animal prey capture.
      • Coral forming animal colonial structures.
    • Platyhelminthes (flatworms), such as:
      • Planarian demonstrating animal regenerative capability.
      • Tapeworm exhibiting animal parasitic lifestyle.
    • Nematoda (roundworms), such as:
      • C.elegans serving as animal model organism for animal developmental study.
      • Hookworm demonstrating animal parasitic adaptations.
    • Annelida (segmented worms), such as:
      • Earthworm showing animal segmentation and animal soil processing.
      • Leech featuring animal blood-feeding adaptations.
    • Mollusca, such as:
      • Octopus demonstrating animal neural complexity and animal problem-solving ability.
      • Snail featuring animal protective shell.
    • Echinodermata, such as:
      • Sea Star showing animal radial symmetry and animal water vascular system.
      • Sea Urchin demonstrating animal spiny defense.
    • Arthropoda, such as:
      • Insects demonstrating animal exoskeleton and animal metamorphosis.
      • Crustaceans featuring animal aquatic adaptations.
      • Arachnids showing animal predatory specialization.
    • Chordata, such as:
      • Vertebrates:
        • Fish demonstrating animal aquatic respiration.
        • Amphibian showing animal dual-phase lifecycle.
        • Reptile featuring animal amniotic egg.
        • Bird demonstrating animal flight adaptations.
        • Mammal showing animal endothermic metabolism:
          • Ape demonstrating animal advanced cognitive capability.
          • Human featuring animal cultural transmission and animal technological development.
  • Animal Ecological Roles, such as:
    • Herbivore Animals consuming plant material.
    • Carnivore Animals preying on other animals.
    • Omnivore Animals utilizing diverse food sources.
    • Detritivore Animals processing dead organic matter.
  • Animal Habitat Types, such as:
    • Marine Animals adapted to saltwater environments.
    • Freshwater Animals inhabiting river, lake, and pond ecosystems.
    • Terrestrial Animals occupying land-based habitats.
    • Aerial Animals specialized for atmospheric navigation.
    • Fossorial Animals adapted for underground living.
  • ...
• Counter-Examples:
  • Plant, which engages in photosynthesis rather than animal heterotrophic feeding and possesses cell walls made of cellulose.
  • Fungus, which has cell walls made of chitin, utilizes absorptive nutrition, and lacks animal motility.
  • Prokaryote, such as Bacteria or Archaea, which lacks animal membrane-bound nucleus and animal cellular organelles.
  • Protist, which may be unicellular or have simple multicellular structures without animal tissue differentiation.
  • Virus, which lacks cellular structure and requires host organism for replication.
• See: Eukaryote, Multicellularity, Heterotroph, Motility, Embryogenesis, Evolutionary Biology, Zoology, Taxonomy, Plant, Bacteria, Fungus, Biodiversity, Ecosystem.

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References

• http://en.wikipedia.org/wiki/Animal
  • Animals are multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their lives. Most animals are motile, meaning they can move spontaneously and independently. All animals must ingest other organisms or their products for sustenance (see Heterotroph).

    Most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals are divided into various sub-groups, including birds, mammals, amphibians, reptiles, fish and insects.

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