Animal Diversity: Exploring the Kingdom Animalia and Body Plans of Animals, Study notes of Biology

Download Animal Diversity: Exploring the Kingdom Animalia and Body Plans of Animals and more Study notes Biology in PDF only on Docsity! Animal Diversity __________ extant species Chapter 18 Estimated that over ___% of all animals that have roamed the earth are extinct - Common ancestor of living animals is estimated to have lived between a billion and 675 million years ago Evolution of Animals • Most taxonomists now agree that animals evolved from a colonial, ________________ during the late Precambrian - it is hypothesized that this protist was similar to the present-day _________________ Although animal species vary greatly in morphology, their great diversity in form can be categorized into a small number of major “body plans” -Body plan → a certain set of ________________ ___________________, integrated into a functional whole (the living animal) -Traditional systematics uses body plans to group animals 1) Symmetry - ________ - _________ Symmetry *Dorsal (____), Ventral (________) - ___________ Symmetry *Dorsal, Ventral, Anterior, Posterior
Cephalization → evolutionary trend toward the ________________ ________________ ________________ ________________ Body plans are formed by: -The symmetry of an animal fits its lifestyle --- think about a jellyfish… 3) Blastopore is destined to become either the mouth or the anus…. - Protostome → Blastopore forms _______ (protos=first; stoma=mouth) - Deuterostome → Blastopore forms ______ Mesoderm is essential for the formation of a coelom (body cavity) 5) Presence or absence of body cavity in Bilateria (triploblastic animals) - _____________ – a=without; koilos=hollow - ___________________ – (pseudo=false) not lined completely with mesoderm tissue - ___________ – cavity completely lined with mesoderm tissue Key Transitions in Body Plan • Evolution of a body cavity (coelom): – _________________________ __________ – Allows digestive tract to be _____ and _________ • storage of undigested food • more complete digestion – Enables internal organs to grow and move independently of outer body wall – Room for a complex circulatory system