There are five types of living things, separated scientifically into five kingdoms, monera (bacteria and blue-green algae), plants, fungi, protista (protozoa and some algae), and animals. With millions of different animal species, this Kingdom portrays the great diversity of life on Earth.
From worms and spiders to primates and carnivores, these 5 characteristics of the Kingdom Animalia are shared by most animal species. Although one can find a few exceptions to these characteristics, scientists working with animals use these characteristics to define the scientific Kingdom Animalia and distinguish members from other Kingdoms.
Starting at the cellular level, animals exhibit obvious differences from other Kingdoms. The cells of animals do not have thick walls as plant cell walls do. Also, animal cells come together to form more complex tissues and organ systems such as the heart, muscles and skin.
All animals have some sort of a digestive tract, although some, such as obligate herbivores like cows, are more complex than others. The basics of any animal’s digestive tract includes a mouth to take in food, an internal system to digest that food and turn it into energy for the animal, and an excretory system to remove waste and toxins from the animal.
Animal cells are diploid cells and contain two copies of each chromosome, with one copy coming from two adults of the species. Most members of the Animalia Kingdom require two parents, a male and a female, to reproduce. In animal reproduction, the male’s sperm must fertilize the female’s internal egg. In a few cases, a single individual animal, such as barnacles, will contain both the male and female reproductive organs.
Diet and Eating
Animals cannot make their own food like plants can. Animals must take in nourishment from other sources. These other sources include both plants and animals that provide the energy an animal needs to survive. That nourishment is then stored as glycogen.
Ability to Move
In short, animals move. They are not physically attached to one location for their entire lifespan. With movement, animals have nerves and muscle tissue that can be controlled by the animal rather than having other forces, such as wind, determine that movement. Most can move from place to place throughout their entire lives, while some have freedom of movement for only a short time in their lives. For example, barnacles have a free moving stage as young larvae.