#AP Biology: Evolution & Ecosystem Disruptions - The Night Before 🚀

Hey! Let's get you feeling super confident about Evolution and Ecosystem Disruptions for your AP Bio exam tomorrow. We'll make sure everything clicks, and you'll be ready to rock! 🎸

#Evolutionary Processes

#How Ecosystem Changes Drive Evolution

• Ecosystem disruptions can be a major catalyst for evolution. When the environment changes, it creates selective pressures that favor some species over others. Think of it like a survival of the fittest reality show! 🎬

• Adaptations are key! These are heritable genetic variations that boost an organism's fitness. The fitter you are, the better your chances of surviving and reproducing. 🧬

• Natural selection is the mechanism. When these heritable variations lead to different reproductive success, natural selection is at play. It's all about who gets to pass on their genes. 💪

• Mutations can introduce new alleles, potentially leading to fitness benefits. Remember, mutations are random and not a direct response to environmental pressures. 🎲

#Competition and Invasive Species

• Competition intensifies when resources become scarce. This can be intraspecific (within a species) or interspecific (between different species). The best competitors win! 🏆

• Invasive species are like uninvited guests that can wreak havoc. They often lack natural predators or competitors in their new environment, allowing them to dominate and disrupt established ecosystems. 🐍

  • Example: The brown tree snake in Guam. This invasive species decimated native bird and mammal populations because it had no natural predators. 🦜

#Disruptions: Natural vs. Human Impact

#Natural vs. Anthropogenic Disruptions

• Anthropogenic impacts are human-caused changes, and they're the biggest troublemakers. Think habitat destruction, pollution, climate change, and the spread of invasive species. 😥

• Natural disruptions also play a role, like floods, fires, and earthquakes. However, human activities are often making these events more frequent and severe. 🔥

• Organisms that cannot adapt quickly enough to these changes are at risk of extinction. It's a race against time! ⏱️

#Final Exam Focus

#Key Topics to Review

• Natural Selection: Understand the four principles: variation, inheritance, differential survival, and reproduction.
• Adaptations: Know how they increase fitness and are heritable.
• Invasive Species: How they disrupt ecosystems and why they are often successful.
• Anthropogenic Impacts: Be able to discuss the major human-caused disruptions and their consequences.

#Common Question Types

• Multiple Choice: Expect questions that test your understanding of key terms and processes.
• Free Response: Be prepared to analyze scenarios involving ecosystem disruptions and their evolutionary consequences.
• Data Analysis: Practice interpreting graphs and charts related to population changes and environmental impacts.

#Last-Minute Tips

• Time Management: Don't spend too long on any one question. If you're stuck, move on and come back later.
• Read Carefully: Pay close attention to the wording of each question. Misreading a question is a common pitfall.
• Stay Calm: Take a deep breath and trust your preparation. You've got this! 💪

#Practice Questions

Practice Question

Multiple Choice Questions

1. Which of the following best describes an adaptation? (A) A short-term physiological adjustment to a change in the environment (B) A heritable genetic variation that increases an organism's fitness (C) A random change in an organism's phenotype (D) A change in behavior due to environmental stress

2. An invasive species is most likely to thrive in a new environment if it: (A) Has a low reproductive rate and is a specialist (B) Has a high reproductive rate and is a generalist (C) Requires specific resources and has many natural predators (D) Is highly susceptible to diseases and environmental changes

3. Which of the following is the most significant anthropogenic impact on ecosystems? (A) Volcanic eruptions (B) Earthquakes (C) Habitat destruction and climate change (D) Natural forest fires

Free Response Question

Scenario: A population of native birds in a forest is declining due to the introduction of a non-native predator. The predator is highly efficient at hunting these birds, and the bird population has not developed any effective defenses against the new threat.

(a) Explain how natural selection might act on the bird population in response to the introduction of the predator. (3 points) (b) Describe two possible adaptations that might evolve in the bird population over time that could increase their chances of survival. (2 points) (c) Discuss one anthropogenic factor that could exacerbate the decline of the bird population and explain how it could do so. (2 points)

Scoring Breakdown

(a)

• (1 point) Natural selection requires variation in heritable traits within a population.
• (1 point) The predator acts as a selective pressure, favoring birds with traits that help them avoid predation.
• (1 point) Birds with these traits will have a higher survival and reproductive rate, passing on those traits to the next generation.

(b)

• (1 point) Any valid adaptation such as camouflage, increased flight speed, or heightened vigilance.
• (1 point) A second valid adaptation such as altered nesting behavior or increased clutch size.

(c)

• (1 point) Identification of an anthropogenic factor such as habitat destruction, pollution, or climate change.
• (1 point) Explanation of how the factor exacerbates the decline, e.g., habitat loss reduces nesting sites, pollution weakens birds, or climate change alters food availability.

Alright, you've got this! Go get 'em tomorrow! 🎉