lecture3 - Lecture 3: Amphibians & New Conquest of the land...

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1 Conquest of the land Reading: Chapter 34: 684-687 Chapter 44: 927-928 Chapter 46: 967 Transition from water to air: why and changes involved Origin of Tetrapods Amphibians - 3 groups: 1) Anura (frogs), 2) Urodela (salamanders) and 3) Apoda (caecilians ) Colonizing the Land • Two fish lineages—coelacanths and lungfishes—evolved lobed or fleshy fins. • Fleshy fin originally an adaptation for swimming and later an exaptation for walking on land • Amphibians, the first terrestrial vertebrates, arose from one of these lineages. 1. Respiration: lungs, internal nostrils (choanae), skin (cutaneous respiration) Transition from Water to Land:Changes Worldwide decline in amphibians Why? • habitat destruction • pollution • diseases • invasive species • increase in UV radiation- developmental problems Transition from Water to Land:Changes 2. Support and movement:
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2 Transition from Water to Land: Changes • Hearing: detecting sound in air (vs. water- lateral line)
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This note was uploaded on 07/03/2008 for the course BIOLOGY 201 B taught by Professor Berta during the Spring '08 term at San Diego State.

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lecture3 - Lecture 3: Amphibians & New Conquest of the land...

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