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reptiles While mammals are warm-blooded (able to regulate their own body
temperature), reptiles are cold-blooded. This means that the temperature of a
reptile’s body is strongly influenced by the air temperature immediately outside of
the reptile’s body. The reptile group of animals also have scales and no hair or
fur. Common reptiles include turtles, lizards, and snakes.
species A species is a very specific type of living thing. Mammals and reptiles are not in
the same species because these are large categories of very different animals.
Dogs and turtles aren’t in the same species either because there is still a lot of
variation between these types of animals. For a type of animal to qualify as a
species, it must be able to mate with other animals of its kind and produce babies
that are the same kind of animal. Humans are a species, and so are
–for
instance
–individual types of snakes or dogs, such as the timberwolf or the coral
snake. There are plant species too, like the Giant Redwood tree, or the tiger lily.
These plants can cross pollinate and reproduce with each other, but not with
other species of plants.
evolve “Evolve” is a life science verb. To evolve is to change in some way in order to
survive. Individual species of animals and plants evolve over long periods of
time
–millions of years. The way the human brain has slowly gotten bigger over
thousands of generations is an example of a way that humans have evolved.
With a larger brain comes higher intelligence and a better ability to survive.
cell A cell is a tiny living thing, so small it can only be seen with a microscope. Every
cell has a thin skin that protects it, called a
membrane . The membrane can take
in food for the cell. Each cell is controlled by a
nucleus , a kind of tiny simple brain
in the middle of a cell. Cells can be part of a larger living thing. Every part of an
animal or plant’s body is made up of tiny cells. A cell can also be an independent
living thing. An
ameba is an example of an organism (living thing) that has just
one cell.
soil Soil is sometimes called “dirt” in informal English. Soil is the dark, dirty stuff
under our feet that plants grow out of. Worms, rabbits, and other hole-digging
animals stay in or under the soil.