CH 31 Part 1- Outline Chordates Non-vertebrate Chordates Vertebrates Subphyum Cephalochordata Subphylum Urochordata Vertebrates Fishes Amphibians Reptiles Birds Mammals

Animal Evolution 2 3.5 Billion years ago first life on Earth 350 (or so) million years ago first tetrapods appear 230 million years ago first mammals appear 100,000 years ago modern humans

3 Animal Evolution

Pg 560a You should be able to completely fill out this chart (on the right) and the chart for chordates by the end of chapter 31.   What differentiates chordates from echinoderms? What is a deuterostome again?

Phylum Chordata Four Main Characteristics Chordates Notochord A dorsal supporting rod Nerve Cord Dorsal tubular nerve cord Anterior portion becomes brain

Phylum Chordata Four Main Characteristics Chordates 6 Pharyngeal Pouches Only seen in embryonic development Tail In embryo if not seen in adult

Pg 560b

Invertebrate Chordates Notochord persists and is never replaced by a vertebral column (Subphylum Cephalochordata) - Lancelets lancelets (Subphylum Urochordata) - Tunicates sea squirts

Pg 560c

Figure 31.1a

Figure 31.1b How are these animals different from other vertebrates you are familiar with (fish, amphibians, etc.)??

Figure 31.2 - Sea squirt, Halocynthia

Sea Squirt Feeding Video!! Sea Squit 13 Sea Squirt Feeding Video!!

Sea Salps 14 Sea Salps Video!!

Vertebrates Subphylum Vertebrata Internal jointed skeleton of vertebrates is living tissue that grows with the animal Main axis of skeleton consists of vertebral columns and a skull that encloses the brain Cephalization is accompanied by sense organs Evolution of jaws and predation Amnion allows reproduction on land

Phylogenetic Tree of the Chordates

Phylogenetic Tree of the Chordates

Vertebrate Features Living endoskeleton with vertebral column Closed circulatory system Paired appendages Efficient respiration and excretion High degree of cephalization Adapted to active lifestyles How have these features allowed vertebrates to grow so large compared with the invertebrates?