 Ecosystem – all organisms living in an area together with their physical environment. ◦ Oak forest  Ecosystems do not have clear boundaries. ◦ Pollen blows from a forest into a field

 Biotic and Abiotic Factors ◦ Biotic Factors – the living and once living parts of an ecosystem, including all plants and animals. ◦ Abiotic Factors – the nonliving parts of an ecosystem  Air, water, rocks, sand, light, temperature  Organisms – an individual living thing. ◦ Species – a group of organisms that can mate to produce fertile offspring.  Homo sapiens

 Populations – all the members of the same species that live in the same place at the same time. ◦ Field mice in a corn field  Communities – a group of various species that live in the same place and interact with each other.

 The place where an organism lives. ◦ Without their natural habitat, plants and animals will die. ◦ Fish that live in the crevices of a coral reef.

 In 1859, Charles Darwin observed that organisms in a population differ slightly from each other in form, function, and behavior. ◦ Some differences are hereditary – passed from parents to offspring  Natural Selection – survival and reproduction of organisms with particular traits. ◦ Darwin proposed that over many generations natural selection causes the characteristics of populations to change.  Evolution – a change in the genetic characteristics of a population from one generation to the next.

 Nature Selects – individuals with genetic traits that make them more likely to grow up and reproduce in the existing environment will become more common in the population from one generation the next. ◦ Lions with sharper claws.  Adaptation – an inherited trait that increases an organism’s chance of survival and reproduction in a certain environment.  Coevolution – the process of two species evolving in response to long-term interactions with each other. ◦ Honeycreeper’s beak is long and curved which lets it reach nectar at the base of a long-curved flower

 Artificial selection – the selective breeding of organisms by humans for specific characteristics. ◦ Fruits, grains, vegetables ◦ Dogs

 Though we often think of natural selection when we talk about evolution, there is also artificial selection: humans decide which plants and animals reproduce, depending on what characteristics humans find desirable.  The bloodhound is an excellent example of artificial selection. This breed of dog is one of the oldest scent hounds in the world. Its lineage can be traced back in Europe to before the time of the Crusades. Most believe the breed originated in Constantinople. The name "bloodhound" does not refer to the dog following a trail of blood. Instead, it refers to the fact that this hound's lineage was tightly controlled to produce an animal whose nose is so reliable, the evidence it finds stands in a court of law.  So how does the bloodhound track? The bloodhound has enlarged, sensitive scent membranes in its nose, containing 230 million olfactory cells (40x more than humans). It can distinguish smells at least a thousand times better than humans. The bloodhound's wrinkly face and long ears help trap and sweep up scents. It has powerful shoulders, which help it keep close to the ground and on a trail sometimes as far as 130 miles.  The nose is not the only characteristic that humans bred this dog for. The dog was also bred to have a desire to work. A dog with a good nose is useless to a human if the dog doesn't want to cooperate.

 Resistance – the ability of one or more organisms to tolerate a particular chemical designed to kill it. ◦ Pesticide Resistance – grasshoppers resistant to pesticide sprayed on corn.

 Archaebacteria – bacteria found in extreme places, such as hot springs.  Eubacteria – very common bacteria found in soil and animal bodies. ◦ Also include blue-green bacteria  Bacteria and the Environment ◦ Break down wastes, allow extraction of nutrients from food  E. coli – found in intestines of humans and other animals. Helps digest food and release vitamins humans need. Other E. coli can cause food poisoning.

 Fungus – an organism whose cells have nuclei and cell walls. ◦ A mushroom is the reproductive structure of a fungus. The rest of the fungus is an underground network of fibers. ◦ Diseases (Athlete’s Foot), cheese flavor, Yeast

 A diverse group of one-celled organisms and their many-celled relatives. ◦ Diatoms, Volvox, Euglena

 Many-celled organisms that have cell walls and that make their own food using the sun’s energy. ◦ Lower plants – no vascular tissue  Mosses ◦ Gymnosperms – woody plants that produce seeds, but their seeds are not enclosed in fruits.  Conifers – Pine trees ◦ Angiosperms – flowering plants that produce seeds in fruit.  Flowers, grasses

 Invertebrates – animals that lack backbones ◦ Worms, clams, oysters  Vertebrates – animals that have backbones ◦ Mammals, birds, amphibians