AP Environmental Science Unit 1 Review (Everything you Need to Know!)

This paragraph introduces the video's purpose, which is to assist students in preparing for their AP Environmental Science exams. The speaker, Mr. Smees, encourages viewers to download a free review packet from the video description, which includes study guides, practice questions, and full-length practice exams. The video begins with a review of Unit 1 on ecosystems, emphasizing the importance of understanding the distinctions between ecosystems, habitats, and environments. The speaker clarifies that an ecosystem involves the interaction of living and non-living things in a specific area, while the environment refers to the entire natural world. The paragraph also addresses common misconceptions about symbiosis and mutualism, highlighting the need for both species in a relationship to benefit for it to be considered mutualistic.

In this paragraph, the focus shifts to biomes, which are regions on Earth with consistent temperature and precipitation patterns, such as tropical rainforests and tundras. The speaker explains how changes in these patterns can lead to biome shifts, with the current example of the tropics expanding due to global temperature rise. The discussion then moves to aquatic biomes, emphasizing the importance of salinity, flow, and depth. The unique characteristics of estuaries are explored, including their brackish water and the adaptations of species like mangroves to high salinity levels. The paragraph also touches on the productivity of estuaries due to the high nutrient content brought by sediments from rivers.

This paragraph delves into the biogeochemical cycles of carbon, nitrogen, phosphorus, and water. The law of conservation of matter is introduced, stating that matter changes forms but is not created or destroyed. The carbon cycle is discussed, highlighting the critical role of photosynthesis, respiration, and human activities like fossil fuel combustion in affecting atmospheric carbon levels. The nitrogen cycle is then explained, with an emphasis on nitrogen fixation, the process by which atmospheric nitrogen is converted into forms usable by plants. The paragraph also covers the phosphorus cycle, which lacks a gas phase and is characterized by slow movement through rocks and sediments. Lastly, the water cycle is described, detailing how solar energy drives the evaporation, infiltration, and transpiration processes.

The paragraph discusses the concept of primary productivity, which refers to the rate of photosynthesis in an area, and distinguishes it from the total amount of photosynthesis. The speaker clarifies the difference between gross primary productivity (GPP) and net primary productivity (NPP), with the latter accounting for energy lost through respiration. The process of calculating NPP is outlined using a simple equation (NPP = GPP - RL). The paragraph also explores how energy moves up the food chain, introducing the concept of the 10 rule, which states that each trophic level only receives 10% of the energy from the level below. The shape of the trophic pyramid is used to illustrate energy flow and the loss of energy at each level. The importance of understanding food webs and the impact of species removal on the ecosystem is emphasized, with the concept of trophic cascades introduced as a powerful effect of predators on the ecosystem structure.

In the concluding paragraph, the speaker reiterates the importance of understanding the concepts covered in Unit 1 for success in the AP Environmental Science exam. Encouragement is given for students to download the free review packet and consider purchasing additional resources for comprehensive exam preparation. The speaker highlights the mutualistic relationship between the student and the provided resources, aiming for a symbiotic relationship where both parties benefit. The video ends with a reminder to think and write like a scholar, reinforcing the goal of academic excellence.