Ecology - AP Biology

Nitrification takes place in the soil and is the process in which ammonium is converted into nitrate. Nitrifying bacteria facilitate this process.

Precipitation is when condensed water vapor falls to Earth. Common types of precipitation include rain, sleet, and snow. In contrast, runoff is water flow across the Earth’s surface.

Primary succession occurs in an environment without previous life, or a barren habitat. Secondary succession occurs in an area that had previously been inhabited but experienced a disturbance, such as a wildfire. In this scenario, there still would be soil.

Primary succession occurs in an environment without previous life, or a barren habitat. The first organisms to grow (called pioneer species) are fast growing, hardy species.

In the precipitation stage of the water cycle, condensed water vapor falls to the Earth’s surface; however, a tree canopy, for instance, may block this precipitation, preventing the precipitation from reaching the Earth’s surface. The intercepted precipitation then evaporates back into the Earth’s atmosphere.

Snowmelt is a type of runoff that results from melting snow.

The theory of plate tectonics describes the movement of the Earth’s crust and mantle. In plate tectonics, water moves through the Earth’s mantle and returns to the surface by volcanoes.

The water cycle requires energy to drive the phase changes that defines different stages of the cycle. The sun in the form of solar energy provides the majority of the energy needed for this cycle.

Trophic level is the term used to a specific point on the food chain. An organism’s trophic level is the place they occupy in the food chain of a particular ecosystem.

Biodiversity refers to the different types of life present on Earth. This can refer to the variety of species in an ecosystem, the genetic variation across the planet, and ecosystem variation.

Endotherms maintain a relatively constant body temperature, independent of their external environment. They can shiver when cold to increase their body temperature through expending energy (“shivering thermogenesis”).

An ectotherm relies on external sources to regulate its body temperature. Endotherms maintain a relatively constant body temperature, independent of their external environment. To regulate their body temperature, endotherms have a higher

Plants make up the bottom trophic level: the producers. This is because plants produce energy through photosynthesis. They do not have to eat other organisms to obtain energy, they make their own using carbon dioxide, water and sunlight.

Herbivores are plant-eating organisms. They are classified in the primary consumer trophic level. An easy way to remember this is to break down the word. Herbs are types of plants, so when we see “herb” in herbivore think of plants. Carnivores eat other animals. Autotrophs and producers need not eat anything to get energy, rather, they make their own.

The latin name consists of the genus and species of the organism. These are the most specific of the taxonomic classifications. The taxonomic classifications are domain, kingdom, phylum, class, order, family, genus, and species.

A community includes populations of different species. The study of a community looks at interactions between species, such as competition, symbiotic relationships, or predation.

Invasive species are organisms that become established outside their native range. In this example, the seed’s native range is the countryside. However, when it is carried by the wind to the forest (an environment outside its native range), it plants itself and establishes a population there. The seed is an example of an invasive species.

The population density is the measure of the population per unit area or volume, and may be measured over land or water.

The carrying capacity refers to the maximum number of organisms that can be sustained by the resources of an environment. The range of a population is simply the area over which the population can be found. Dispersion refers to the different regions where a species is found within a given area. Competition is the use of limited resources between multiple members of a population, or multiple species within a niche.

The earth's habitats and ecosystems are dispersed based on air circulation, rainfall, and topography. For example, when looking at the globe, we may notice that the world's major grasslands are always leeward of major mountain ranges, or that tropical rain forests are located around the equator. Why do grasslands fall on the leeward side of mountain ranges, and tropical rainforests at the equator? As the air travels up the mountain, it condenses and precipitation occurs. Once the air reaches the leeward side, it is dry, resulting in the grasslands and plains. Tropical rainforests are located at the equator, an area that gets constant sunlight and rainfall regardless of the earth's tilt. The dispersion of the earth's habitats and ecosystems is very dependent on such environmental factors.