1.Dear reader, the video is a little lower. The animal kingdom, scientifically known as Animalia, consists of multicellular organisms with eukaryotic cells. Almost every animal survives by feeding on organic substances, using oxygen for respiration, and relying on specialized muscle cells that allow movement. During early embryonic development, animals pass through a stage called the blastula, a hollow ball of cells. Evolutionary evidence shows that every modern animal traces its ancestry back to a single common predecessor. Researchers have officially documented more than 1.5 million living animal species.
Insects represent the overwhelming majority, with roughly 1.05 million identified species. Scientists have also recorded over 85,000 species of molluscs and approximately 65,000 vertebrate species. Despite these discoveries, estimates suggest that the Earth’s true animal diversity may reach 7.77 million species, leaving millions yet to be identified. The size of animals varies enormously. Some microscopic species are only 8.5 micrometres (0.00033 inches) long, whereas the largest can grow to nearly 33.6 metres (110 feet). Across oceans, forests, deserts, and countless other habitats, animals interact with one another and with their surroundings, creating highly interconnected ecosystems and complex food chains.
