We can divide adaptations into two basic categories:
1-Physical adaptations
2-Behavioural adaptations
Adaptations
Organisms, from microbes to plants and animals, inhabit environments that can change to become drier, hotter, colder, more acidic, darker and sunnier -- with an almost infinite number of variables. Organisms with genetic advantages, such as a mutation that helps them survive the new conditions, pass down the change to descendants, and it becomes prevalent in the population to be expressed as an adaptation. The three basic types of adaptations, based on how the genetic changes are expressed, are structural, physiological and behavioral adaptations. Most organisms have combinations of all these types.
Structural
An organism's environment shapes its appearance through structural adaptations. Desert foxes have large ears for heat radiation and Arctic foxes have small ears to retain body heat. Seals have flippers to navigate water and raccoons have separate, flexible digits to manipulate food. White polar bears blend into ice floes and spotted jaguars into the speckled jungle shade. Trees may have corky bark to protect from wildfires. Structural modifications affect organisms at different levels, from the way a knee is hinged to the presence of large flight muscles and sharp eyesight for predatory birds.
Physiological
Based on body chemistry and metabolism, physiological adaptations usually don't show from the outside. They consist of things like more efficient kidneys for desert animals like kangaroo rats, compounds that prevent blood coagulation in mosquito saliva, or the presence of toxins in plant leaves to repel herbivores. Laboratory studies that measure the contents of blood, urine and other body fluids, that trace metabolic pathways, or microscopic studies of an organism's tissues are often necessary to identify physiological adaptations. Sometimes detecting them is difficult if there isn't a common ancestor or a closely related species with which to compare findings.