AP Environmental Science Unit 2 Review (Everything you Need to Know!)

Jordan Dischinger-Smedes2 minutes read

Before reviewing Unit 2 of the AP Environmental Science course, ensure you have the "ultimate review packet study guide" printed out, as it highlights essential concepts like biodiversity at genetic, species, and ecosystem levels, and explains the impact of human activities on ecosystem services. Understanding ecological principles, such as the theory of island biogeography and the importance of ecological succession, is crucial for grasping how organisms adapt and how ecosystems maintain balance amidst environmental changes.

Insights

  • Ensure you have the "ultimate review packet study guide" printed out before starting the review of Unit 2 in the AP Environmental Science course, as it will help you answer practice questions and understand key concepts effectively. Understanding biodiversity is essential, as it encompasses three levels: genetic diversity, which enhances survival during environmental changes; species diversity, which contributes to ecosystem resilience; and ecosystem diversity, which showcases the variety of habitats that support different life forms.
  • Human activities significantly impact ecosystem services, as highlighted by the Deepwater Horizon oil spill, which disrupted fishing, coastal ecosystems, and tourism. Additionally, the theory of island biogeography illustrates how species richness is influenced by proximity to the mainland and island size, emphasizing the importance of habitat diversity in supporting various species and the potential consequences of habitat loss on ecological balance.

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Recent questions

  • What is biodiversity in simple terms?

    Biodiversity refers to the variety of life forms in an ecosystem, encompassing the different species, genetic variations, and ecosystems present. It is essential for maintaining ecological balance and resilience, as diverse ecosystems can better withstand environmental changes and disturbances. Biodiversity can be categorized into three levels: genetic diversity, which involves the variety of genes within a species; species diversity, which looks at the number of different species and their population balance; and ecosystem diversity, which considers the variety of ecosystems in a given area. Understanding biodiversity is crucial for conservation efforts and ensuring the sustainability of natural resources.

  • How do human activities affect ecosystems?

    Human activities can significantly disrupt ecosystems and their services, leading to detrimental effects on the environment and biodiversity. For instance, pollution from industrial activities, such as the Deepwater Horizon oil spill, can contaminate water sources, harming marine life and disrupting local economies reliant on fishing and tourism. Deforestation, urbanization, and agricultural expansion can also lead to habitat loss, reducing species diversity and altering ecosystem functions. These disruptions can diminish the natural services ecosystems provide, such as clean air and water, pollination, and climate regulation, ultimately impacting human well-being and the health of the planet.

  • What is ecological tolerance?

    Ecological tolerance refers to the range of environmental conditions that a species can endure while still being able to survive and reproduce. Each species has specific limits for factors such as temperature, moisture, and salinity, beyond which they may experience stress or even death. For example, humans thrive within a narrow temperature range of 97 to 99 degrees Fahrenheit; exceeding this range can lead to physiological stress. Understanding ecological tolerance is vital for predicting how species will respond to environmental changes, such as climate change, and for developing conservation strategies to protect vulnerable species.

  • What are ecosystem services?

    Ecosystem services are the benefits that humans derive from natural ecosystems, which can be categorized into four main types: provisioning services, such as the supply of food, water, and raw materials; regulating services, which include climate regulation and disease control; supporting services, like nutrient cycling and soil formation; and cultural services, which encompass recreational, aesthetic, and spiritual benefits. These services are essential for human survival and well-being, as they contribute to economic stability and quality of life. Protecting and maintaining healthy ecosystems is crucial for ensuring the continued availability of these vital services.

  • What is ecological succession?

    Ecological succession is the process by which ecosystems change and develop over time, involving a series of stages that lead to a stable community. There are two main types of succession: primary succession, which occurs in lifeless areas where soil has not yet formed, such as after a volcanic eruption, and secondary succession, which takes place in areas where a disturbance has cleared an existing ecosystem but left the soil intact, like after a forest fire. During succession, pioneer species, such as moss and lichen, colonize the area and help create conditions for other species to thrive. This process is essential for ecosystem recovery and stability, and keystone species play a critical role in maintaining balance within these communities.

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Summary

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Understanding Biodiversity and Ecosystem Services

  • Ensure you have the "ultimate review packet study guide" printed out before starting the review of Unit 2 in the AP Environmental Science course, as it will help you answer practice questions and understand key concepts effectively.
  • The first topic in Unit 2 is biodiversity, which is defined as the variety of life forms in an ecosystem, and it is crucial to understand the three levels of biodiversity: genetic, species, and ecosystem biodiversity.
  • Genetic biodiversity refers to the variety of genes within a population, which increases the chances of survival during environmental changes; for example, a population of sparrows with high genetic diversity may have individuals with traits that allow them to adapt to drought conditions.
  • Species diversity is measured by species richness (the total number of different species) and species evenness (the balance of population sizes among species); a higher species evenness in an ecosystem, like Forest Number One, can provide resilience against diseases affecting dominant species.
  • Ecosystem biodiversity refers to the variety of ecosystems in a region; for instance, a tropical rainforest has high ecosystem diversity due to its varied habitats, while a desert has lower diversity and supports fewer species.
  • Ecosystem services are the financial benefits humans derive from ecosystems, categorized into four types: provisioning services (e.g., wood for furniture), supporting services (e.g., pollination by bees), regulating services (e.g., climate stabilization by trees), and cultural services (e.g., tourism revenue from natural sites).
  • Human activities can disrupt ecosystem services, as illustrated by the Deepwater Horizon oil spill, which negatively impacted fishing, coastal ecosystems, and tourism due to oil contamination.
  • The theory of island biogeography states that islands closer to the mainland have higher species richness due to easier migration, while larger islands support more species due to greater habitat diversity; this is represented by an inverse relationship between distance from the mainland and species number.
  • Ecological tolerance refers to the range of environmental conditions a species can endure; for example, humans have an optimal body temperature range of 97 to 99 degrees Fahrenheit, and exceeding this range can lead to physiological stress or death.
  • Natural events that disrupt ecosystems can be categorized into periodic (e.g., rainy seasons), episodic (e.g., hurricanes), and random events (e.g., asteroid impacts), while gradual climate changes occur over tens of thousands of years due to natural cycles in Earth's orbit, affecting climate and sea levels.

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Environmental Change and Species Adaptation

  • Sea level rise is caused by the melting of glacial and polar ice sheets and the thermal expansion of ocean water, leading to potential flooding of low-lying coastal ecosystems like estuaries and altering light penetration in shallow waters, which can disrupt coral reef ecosystems.
  • The adaptation of species, such as Homo habilis, is crucial for survival in changing environments; approximately 2 million years ago, a new thumb muscle arrangement allowed for a tighter grip, enabling the creation of more efficient stone tools for accessing energy-rich marrow from animal bones, providing a significant survival advantage.
  • Organisms either adapt to environmental disturbances or face extinction; early hominids adapted to new grassland conditions by developing the ability to stand upright and use tools effectively, which facilitated their survival and reproduction in changing habitats.
  • Ecological succession includes primary succession, where pioneer species like moss and lichen colonize bare rock and create soil through chemical weathering, and secondary succession, which occurs in disturbed soil with existing vegetation; keystone species, such as wolves and beavers, play a critical role in maintaining ecosystem balance, and their removal can lead to ecosystem collapse.
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