1 minute read
Key Takeaways
by AudioLearn
KEY TAKEAWAYS
• A circulatory system is necessary when diffusion is insufficient in getting oxygen to all animal tissues.
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• The respiratory system is different in different animals but involves structures that exchange oxygen and carbon dioxide.
• The animal digestive system involves ingestion, mechanical digestion, chemical digestion, absorption, and elimination of waste.
• Animal organisms will have an innate and sometimes an adaptive immune system, the latter of which is evolutionarily younger.
• The endocrine system involves endocrine glands that send hormones through the circulatory system to act on distant organs.
• Reproduction can be asexual or sexual in animals, with a variety of mechanisms of reproduction possible.
