Life on Earth Con.

• Small changes is evolution
• all systems evole together 
• heart is pump in open and closed
• all cells have to be surrounded by water
• animals started running faster and needed more oxygen
• Amphibian-cold blooded, not very big or active, heart works well-3 chambers
• Four chambers-Birds and mammals
• Veins can grow-cells do not fit together
• Lymphatic system-lymph baths every cell-lymph tissue=blood plasma
• We developed from protists
• Small animals could breather through skin
• Gills evolved early on, not only fish have
• Tracheal tubes have spiracles in insect
• Gases exchanged rapidly, lungs inflate gills
• Air pushs over gills which are extensions of blood vessels
• Lungs have branches with air sacs called the Alvelus
• Branched allows for more surface area to be covered
• Excretory Systems
• Chyme is thrown up food, which the somach adds water to
• Digestion chemically rots food
• Villi increase the surface area, they are filled with blood vessels
• Large intestine absorbs water
• Diffusion=microorganism
• Flame cells fill u and contract moving waste to a excretory tubule
• Malpighian tubes-Kidneys, extract waste
• Nephridia serve the same functions because they are kidneys