Heterotrophy: Animals are all heterotrophic, meaning they must consume other organisms to obtain energy and nutrients. This sets them apart from autotrophic organisms, like plants, which produce their own food through photosynthesis.
Multicellularity: Animals are all multicellular organisms, meaning their bodies are composed of multiple cells that work together to perform various functions. This complexity allows for specialization of cells and tissues, leading to greater complexity and diversity.
Reproduction: Most animals reproduce sexually, involving the fusion of gametes (eggs and sperm) to produce offspring. This mode of reproduction introduces genetic variation and contributes to the diversity of animal species.
Sensing and responding to the environment: Animals have specialized sensory organs that allow them to detect and respond to various stimuli in their environment. This ability enables them to adapt to changing conditions, navigate their surroundings, and interact with other organisms.
Organization: Animals are organized into various hierarchical levels, from cells to tissues to organs and organ systems. This organization allows for efficient coordination of bodily functions and specialization of tasks.
Evolutionary diversity: Animals exhibit an incredible diversity of forms, behaviors, and adaptations. This diversity is a result of millions of years of evolution and ecological pressures that have shaped and refined animal lineages.