Welcome to Chordata Introduction to Vertebrates 30 1

Welcome to Chordata Introduction to Vertebrates

30 -1 Chorates 1. Chordates belong to the phylum Chordata. Kingdom Animalia 3. Chordates must have four characteristics: Dorsal hollow nerve cord (supporting rod) Notocord Pharyngeal pouches A tail

2. Examples Include 1. Fish 2. Amphibians 3. Reptiles 4. Birds 5. Mammals

4. Pharyngeal Pouches Paired structures in throat regions Some chordates have them develop into gills used to exchange gas We are chordates so where are yours? You had as an embryo while pharynx was forming

5. 96% of all chordates have vertebral column, or backbone. They are placed into the subphylum Vertebrata. The backbone replaces the notochord during development. This backbone is part of the endoskeleton (internal skeleton) Insects have exoskeletons (hard outer shell on the outside of organism)

6. Using the image above, are vertebrates or invertebrates more evolved (complex)? How do you know? More complex because they have adapted more complex structures over time

7. The backbone, also known as the spine, is made of …. Vertebrae

8. Although all vertebrates are chordates, not all chordates are vertebrates Tunicates Lancelets

Amphibians • An amphibian is an animal that lives part of it’s life in water and part on land

Amphibians • Amphibian means “double life” • They belong to the phylum Chordata

Amphibians have 3 Groups • Examples include: • Anura (Frogs & Toads) • Urodela (Salamanders & Newts) • Apoda (Caecilian)

Amphibian Classification Amphibians are broken down into gruops according to their body structures

Amphibians • Frogs need a moist habitat because: • Skin cannot hold in moisture • Absorb oxygen through skin • Lay their eggs

Reproduction Amphibians must have water to… Reproduction (eggs are laid in water and tadpoles have gills)

Homeostasis • Homeostasis is the ability to maintain stable internal conditions • Ectotherms: Do not produce much internal heat “Cold-Blooded” • Endotherms: Able to regulate their internal body Temperature “Warm-Blooded”

Ectotherms have Benefits Frogs do not maintain their body heat Must get their heat from surrounding area Example: Sitting in sun on a lily pad When they get cold, everything slows down inside Live of body fat and go long periods of time without food

Estivation In hot, dry climates amphibians can go through estivation Similar to hibernation (period of inactivity) but amphibian searching for cooler spot underground

Amphibians • Scientists believed they changed slowly over time from fish.

Frog Life Cycle Eggs Laid

Frog Life Cycle Eggs Develop

Frog Life Cycle Tadpole hatches and grow

Frog Life Cycle Tadpole grows and begins to get appendages

Frog Life Cycle Tadpole grows and begins to get appendages

Frog Life Cycle As the frog develops, and its tail hrinks, it begins to move out of the water

Frog Life Cycle Adult Frog