What is natural selection? This is the idea that a specific physical trait of a population made it more likely to survive the given environment. Some researchers believe that language was created in order to help humans survive. A group of hunters communicating to become more effective is one example of how this could happen. If a species lacks a certain trait that will allow it to survive, there are two options: Either the species dies out or it develops the missing trait.

This process results in ADAPTATIONS, the behaviors and physical characteristics of species that allow them to live successfully in their environment. Every organism has a variety of adaptations that are suited to its specific living conditions. Adaptations can be either physical or behavioral. A physical adaptation is some type of structural modification made to a part of the body. A behavioral adaptation is something an animal does – how it acts - usually in response to some type of external stimulus.

Body Parts Many animals have developed specific parts of the body adapted to survival in a certain environment. Among them are webbed feet, sharp claws, whiskers, sharp teeth, large beaks, wings, and hooves. Webbed Feet To aid swimming, many animals have adapted and evolved with webbed feet. Webbed feet help animals propel themselves through the water with ease. This can help the animal swim faster to catch prey or escape a predator. Whiskers They serve as an important purpose for many animals. Whiskers around the face, specifically the mouth area, help the animal feel its way through tight spots. In a way, they serve as "feelers," telling the animal whether or not it can fit into a specific area.

Body Coverings An animal’s body covering is one clearly visible adaptation. Body coverings help to protect animals in diverse environments -- from the land to water, from the arctic to the desert. Mammals have hair, or fur, that helps insulate their bodies. Birds also have a very protective covering: feathers. The feathers keep the bird warm in winter, help it fly or swim, and help fan the bird in hot weather. Amphibians and reptiles have body coverings that protect them as well. Amphibians have moist, slick skin that is well suited for the water. Reptiles have tough, dry skin covered by scales. Insects, such as the cockroach, have coverings that enable them to squeeze into very small places.

Striped Fur Striped fur is one variation of a special adaptation called camouflage. Striped fur, in most cases, helps animals blend into their environment. This helps the animal in one of several ways, including hiding from predators and sneaking up on prey. Striped fur, as in the case of a tiger's vertical stripes, serves the animal by helping it match the surrounding vegetation, thus making it nearly invisible to other animals. In other animals, like the skunk, the stripes serve as a warning to predators. In this way, the stripes serve as a defense mechanism.

Spotted Fur Another adaptive type of body coloring is spotted fur. Spotted fur is similar to striped fur in the fact that it serves as camouflage. Many animals with spotted fur live in heavily wooded forest areas. One example is the jaguar, which lives in the rain forest. The jaguar's spotted fur helps it blend in with the small patches of sun that reach the rain-forest floor. These patches, mixed in with the shade, produce an effect that highly resembles a jaguar's coat. Another animal with spotted fur is the snow leopard. The snow leopard, with a white coat and black spots, lives in wooded areas as well, using its coat to hide amid the trees and snow.

Scales One final type of body covering is scales. Scales serve a purpose different than that of fur and feathers. Scales are mainly protecting animals from the environment. For instance, anacondas and other snakes have scales to protect their bodies from the variety of terrain they encounter. In the case of the anaconda, its habitat is largely made up of water. In the case of other snakes, the climate may be dry and the land sandy and rocky; so they cannot afford to lose water from their body. Scales help protect the body of the animal in an instance where skin, fur, or feathers would become damaged or destroyed.

Have you ever been tricked by something that was fake? Smaller, weaker animals have to imitate stronger animals to stay alive. These "copycats" are called MIMICS. If insects or other less powerful animals can trick their predators into thinking they are a different animal by the sounds they make, or the colors on their body, they just might survive a little longer. Take a look at these two butterflies. One is a Monarch and very yucky to eat. The other is a Viceroy and very yummy. If an animal eats a Monarch butterfly and HATES it, it will stay away from ALL butterflies that look like Monarchs. This helps the Viceroy because many animals mistake it for a Monarch.

Ecosystem Ecosystem- All the living and nonliving things that interact in a particular area. – A prairie is an example of an ecosystem Ecology- From the Greek root words oikos (house or place) and logos (study). – The study of how living things interact with each other in their environment.

To live or not to live….. Biotic factors – The living parts of an ecosystem – For a prairie: prairie dogs, hawks, grass – As well as worms, fungi and bacteria that live in the soil Abiotic factors- The nonliving parts of an ecosystem. – For a prairie: soil, water, sunlight, oxygen, temperature.

Habitats Organism- one specific living thing –T–The organism needs to obtain food, water, shelter and other things to survive, grow and reproduce from its surroundings. Habitat – T he place where an organism lives to fulfill those needs. –A–A single ecosystem may have many habitats. –W–Why do organisms live in different habitats? They have different requirements for survival.

Populations Species- a group of organisms that are physically similar and can reproduce with each other. Population- all members of one species in a particular area. – Examples: All pigeons in New York City Prairie dogs in a Texas town All daisies in a field – Non-example: All the trees in a forest because they are not all the same species. – There could be pines, maples, or other trees

Ecosystem Community Population Organism

Changes in Population Size Population Density- the number of individuals in a specific area. – You counted 50 monarch butterflies in 10 square meters. Populations can change in size : – New being added: Births are the major way new individuals are added. Immigration – moving in – Individuals leaving: Deaths are the major way individuals leave. Emigration – leaving a population

Limiting Factors When conditions are good a population will generally increase. However, it cannot grow forever. Limiting factor- an environmental factor that prevents a population from increasing. – Food: Sometimes food becomes scarce. – Space: usually a limiting factor for plants – Weather: flood, hurricane, frost, temperature Carrying capacity: the largest population that an environment can support.