Bellwork 1: 1-8-2014 • Briefly write about a real scientific observation you made over the break. • I will only call on 3 of you to share
Vertebrates Chapter 3
Vertebrates • There are more than 50,000 species of vertebrates in this world. • A vertebrate is an animal with a backbone that supports and protects the spinal cord.
Vertebrates All Have • All vertebrates have: • Backbones, brains, craniums (skulls), closed circulatory systems with veins, arteries, and capillaries, continuously beating heart to keep blood flowing
Vertebrates 2 Groups • Vertebrates can be divided into two groups: • Ectotherms& Endotherms • Ectotherms are animals that use the environment to regulate their body temperatures. • They generally bask in the sun or bury themselves for heat or cooling • Reptiles, fish, and amphibians are all ectotherms
Endotherm • Endotherms are organisms that internally regulate their body temperatures. • Their internal temperature remains generally the same whether they are in hot or cold environments • Birds and mammals are examples of endotherms.
Vertebrates • Vertebrates’ tissues are made mostly of salty water • This tissue freezes/dies at 31.1’ F • Most vertebrates live in areas with temperature ranges from 32’-122’F • Some have adapted to harsher environments
Adaptations • Polar bears have thick layers of fat to insulate them from the cold • Some fish have chemicals in their blood that act like antifreeze to allow them to live in cold arctic water
Review • 1. What do vertebrates have in common? • Backbones, brains, craniums (skulls), closed circulatory systems with veins, arteries, and capillaries, continuously beating heart to keep blood flowing • 2. What are the two general groups of vertebrates? • Ectotherms, endotherms
Review • 3. What distinguishes these two groups? • Their ability, or lack there of, to regulate their internal temperature • 4. In general, what animals are part of each group? • Ectotherms: reptiles, fish, amphibians • Endotherms: birds, mammals
Ectotherms • Ectotherms’ body temperature and body functions are regulated by the outside temperature • Not cold-blooded: ectotherms are not called cold-blooded anymore because some actually have a higher internal temperature than endotherms
Air vs. Water temp • Because air temperatures change more than water temperatures, land ectotherms vary more than water ectotherms • Due to this variance, land ectotherms seek sun or shade to help regulate these changes
Ectotherms Regulation • Many ectotherms hide from predators at night because they are sluggish from lack of heat energy • Others prey at night (mostly in hot climates) and stay out of extreme temperatures during the day
Ectotherm Regulation • Ectotherms can also change color to help regulate their body temperatures. • Darker colors absorb heat while lighter colors reflect heat.
Review • 1.What is the distinguishing feature of ectohterms? • They regulate their internal temperature using the sun’s energy • 2. Why is cold-blooded a confusing term to describe ectotherms? • Many ectotherms have warmer internal temperatures that endotherms.
Review • 3. Which organisms have an easier time regulating their body temperatures, ectotherms that live on land or water? Why? • Those that live in water • Because water temperature is not as volatile as air temperature.
Review • 4. What are some ways that ectotherms regulate their body temperatures? • Basking, burying, changing color
Reptiles • Over 7000 species of reptiles • The study of reptiles and amphibians is herpetology • Herpoin Greek is “to creep or crawl” • All reptiles have lungs and scaly skin
Reptiles • Most reptiles shed their entire skin at once rather than one cell at a time like us!
Reptiles • Scales protect the skin underneath from drying out • Retiles have bone skeletons and most have teeth • Their teeth range from blunt crushing teeth to thin needle-like fangs
Reptiles • Many reptiles have a muscular, flexible, sticky tongue for catching insects.
Reptiles • Reptiles generally have well developed organs. (snakes are deaf and some lizards don’t have eyes) • Crocodiles and alligators have very advanced organ systems that have allowed them to thrive for millions of years.
Reptiles • All reptiles reproduce through internal fertilization • Some lay leathery eggs and the young are hatched • Others store their eggs inside their bodies and the young are born live
Reptiles • Young reptiles look like miniature adults • Most reptile mothers do not take care of their young
Common Reptile Groups • 1. Turtles • 2. Lizards • 3. Snakes • 4. Alligators and Crocodiles
Turtles • Turtles’ bodies are protected by a shell formed of plates of bone • Some shells can support a weight 200 X their own!
Turtles • Turtles are toothless, but have a beaklike structure to eat plants and animals