An animal is a multicellular, eukaryotic organism that belongs to the biological kingdom Animalia. These organisms are characterized by their ability to move voluntarily, their heterotrophic mode of nutrition (meaning they obtain nutrients by consuming other organisms), and their ability to sense and interact with their environment.
Here are some key characteristics of animals:
Multicellular: Animals are composed of multiple cells that are specialized to perform specific functions.
Eukaryotic: The cells of animals have a nucleus that contains their genetic material, as well as other specialized structures called organelles.
Heterotrophic: Animals cannot produce their own food (like plants do through photosynthesis). They must consume other organisms or organic material for energy.
Movement: Most animals have the ability to move in some way, though the degree of mobility can vary significantly from one group to another.
Sensory and Nervous System: Animals have complex sensory and nervous systems to interact with their environment. They can respond to stimuli such as light, sound, temperature, and pressure.
Reproduction: Most animals reproduce sexually, which involves the combination of genetic material from two parents.
The kingdom Animalia is very diverse and includes everything from sponges to insects to birds to mammals.
Therefore, spiders are animals. More specifically, they belong to the kingdom Animalia, the phylum Arthropoda, and the class Arachnida. They are part of the order Araneae, which encompasses all spiders. Arachnida also includes other creatures like scorpions, mites, and ticks. So spiders are not only animals, but are also arthropods and arachnids.
Wealth consists not in having great possessions, but in having few wants. – Epictetus