#AP Environmental Science: Unit 2 - Ecosystems and Biodiversity

Hey there! Let's dive into Unit 2, where we'll explore how organisms interact with their environment. This unit is all about connections and how everything is linked. Get ready to see the bigger picture! 🌍

#Biodiversity: The Variety of Life

Biodiversity is all about how much variety there is in a specific place. It's not just about counting species; it's about understanding how diverse and healthy an ecosystem is. This is a really important concept, so let's break it down:

• Biodiversity: The variety of life in a particular habitat or ecosystem. It's like the spice rack of nature – the more variety, the richer the flavor! 🌶️

  • Ecological Relevance: This is how we measure the importance of an area based on its biodiversity. It helps us decide where to build, conserve, etc.

#Species Diversity

• Species Diversity: The total number of different species in an ecosystem. A high number of species usually means a healthier ecosystem. Think of it like a diverse team – each member brings unique skills! 🤝

  • Species Richness: Just the number of different species present. If you have 10 species, the richness is 10. * Species Evenness: How evenly distributed the species are. If you have 100 animals, and 90 are squirrels, evenness is low. If you have 33 squirrels, 33 rabbits, and 34 birds, evenness is high.

#Genetic Diversity

• Genetic Diversity: The variety of genes within a species. More genetic diversity means a population is more resilient to changes. It's like having a backup plan for everything! 🧬

  • Alleles: Different versions of a gene (like different eye colors). More alleles mean more genetic diversity.
  • Phenotypes: The physical traits that result from genes (like blue eyes or brown hair).

#Shannon's Index

• Shannon's Index: A mathematical way to measure species diversity using both species richness and evenness. It helps ecologists get a more accurate picture of ecosystem health.

Image from Pixabay

(a) Define species richness and species evenness. (2 points)
(b) Compare the species richness of the grassland and the forest. (1 point)
(c) Compare the species evenness of the grassland and the forest. (1 point)
(d) Explain how high biodiversity can make an ecosystem more resilient to environmental changes. (2 points)

#Ecosystem Services: Nature's Benefits

Ecosystem services are all the good things nature does for us – things we often take for granted! These services are essential for our survival and well-being. Let's explore the main types:

• Ecosystem Services: The benefits humans get from the natural world. It's like nature giving us a helping hand! 🤝

  • Provisioning Services: The direct products we get from nature. Think of them as the goods we take from nature's store. 🍎
    • Examples: Wood, food, water, medicine
  • Regulating Services: The natural processes that keep our environment stable. They're like nature's air conditioning and water filters. 💨
    • Examples: Climate regulation, water purification, pollination
  • Cultural Services: The non-material benefits we get from nature. They're like nature's therapy and entertainment. 🏞️
    • Examples: Recreation, spiritual value, aesthetic beauty
  • Supporting Services: The basic processes that allow all other services to exist. They're like the foundation of a house. 🏠
    • Examples: Nutrient cycling, soil formation, photosynthesis

Image from Pixabay

#Ecological Tolerance: Limits to Survival

Every species has its limits. Ecological tolerance is about how much a species can handle before it starts to suffer. It's like having a comfort zone – stray too far, and things get uncomfortable! 🌡️

• Ecological Tolerance: The range of conditions (temperature, water, etc.) that a species can survive in. It's like a species' personal comfort zone.

  • Resistance: The ability to withstand a disturbance. It's like being able to hold your breath underwater – how long can you last? 🤿
  • Resilience: The ability to recover from a disturbance. It's like bouncing back after a fall – how quickly can you get back up? 🤸

#Natural Disruptions to Ecosystems

Nature is always changing, and sometimes those changes can be dramatic. Natural disruptions can have a big impact on ecosystems, sometimes as much as human-caused ones. It's like nature hitting the reset button. 🔄

• Natural Disruptions: Natural events that change ecosystems. They are part of the Earth's natural cycles, but can still have big impacts. 🌪️

  • Examples: Volcanic eruptions, earthquakes, wildfires, climate change
  • Metabolic Processes: Slow but drastic changes caused by chemical processes like photosynthesis or the carbon cycle. These can lead to long-term changes in ecosystems.

#Ecological Succession: Ecosystem Recovery

After a disturbance, ecosystems don't just stay damaged. They go through a process of recovery called ecological succession. It's like watching a garden grow back after a storm. 🌱

• Ecological Succession: The process of ecosystem recovery after a disturbance. It's like nature's way of healing itself.

  • Pioneer Species: The first species to colonize a disturbed area (like lichens). They're like the first settlers in a new land. 🧑‍🌾

#Primary Succession

• Primary Succession: Succession that starts with no soil. It's like starting from scratch. 🚧

  • Examples: After volcanic eruptions or on bare rock. Think of a parking lot turning into a forest – it takes a long time!

Image from Wikipedia

#Secondary Succession

• Secondary Succession: Succession that starts with soil already present. It's like starting with a head start. 🚀

  • Examples: After fires or floods. Think of a forest growing back after a fire – it's much faster than primary succession.

Image from Pixabay

#Final Exam Focus

Okay, you've made it through Unit 2! Here's what to really focus on for the exam:

• Biodiversity: Understand the different types (species, genetic) and why they are important. Focus on species richness and evenness.
• Ecosystem Services: Know the four categories and be able to give examples of each. Understand their importance to human well-being.
• Ecological Succession: Be able to compare and contrast primary and secondary succession. Know what pioneer species are.

#Last-Minute Tips

• Time Management: Don't spend too long on any one question. If you're stuck, move on and come back later.
• Common Pitfalls: Watch out for tricky wording in multiple-choice questions. Make sure you fully understand the question before answering.
• FRQ Strategies: Plan your answers before you start writing. Use clear and concise language. Make sure you address all parts of the question.

Remember, you've got this! You've learned a lot, and you're ready to ace this exam. Stay calm, stay focused, and trust in your preparation. Good luck! 🍀