Vertebrates: Reptiles, Birds & Mammals By: Aura, Megan, & Maura
Jan 18, 2018
Vertebrates:Reptiles, Birds & MammalsBy: Aura, Megan, & Maura
Reptiles-three chambers in the heart [w/
a small fourth] -lungs-scales
-external fertilization-oviparous [lays eggs]
-reptiles lay amniotic eggs with shells
-reptiles have scales with protein keratin in them to create a waterproof barrier which also
prevents dehydration.-the scales help separate them
from amphibians; prevents breathing through their skin
-reptiles are ectothermic: they absorb external heat as a main
source of insulation-conserve energy by basking in the sun when cold, and finding
shade when too hot-birds and reptiles both have
vertebrates and both have the ability to lay eggs
Birdies-four chambers in the heart
-lungs-feather/skin
-external fertilization-oviparous [lays eggs]
-wings are remodeled from tetrapod limb. Shape and arrangement of
feathers form the wing into airfoils. Bones are hollow and have
honeycomb structure that’s filled with air
-birds believed to have evolved from certain species of dinosaurs that also
are related to reptiles-feathers are produced by similar tissues that produce scales; birds
have scales on their feet-flightless birds have no sternal keel
and pectoral muscles are undeveloped; feet made to walk on land and usually heavier in weight
Five Adaptations for Flying
1. Large pectoral muscles connecting to the sternum give flapping powers
2. Efficient respiratory and circulatory systems and a four chambered heart to keep tissues supplied with oxygen
3. No urinary bladder, females have one ovary to cut down on weight
4. Toothless to cut down weight of the skull
5. Hollow bones– help them fly
Mammals four chambers in the heart lungs skin, hair internal fertilization viviparous [live birth] jaws of later evolved mammals had
less bones and jaw joint bone has changed; in fish & reptiles, jaws are composed of several fused bones and two small bones
like birds, mammals are endothermic, and most have a high metabolic rate. Reptiles, though, are considered “cold-blooded” because they do not use their metabolism extensively to control their body temperature.
Physical Features Unique to Mammals
Physical features of mammals:
1. mammary glands: produce milk for offspring
2. extra layer of fat beneath skin to retain heat
3. differentiation of teeth: come in a variety of shapes & sizes adapted for chewing many different kinds of foods