Human Impacts on Biodiversity: Overexploitation, Habitat Fragmentation, and Domestication

Conceptual Acronym: The lecturer introduces the impacts on biodiversity starting with the letters "O b".
Overexploitation Definition: This refers to the act of using resources or exploiting them to the point of exhaustion, often driven by the desire to get confidence or maximize gain. It encompasses several specific human activities: * Overfishing: The removal of a species of fish from a body of water at a rate that the species cannot replenish, resulting in those species becoming underpopulated. * Overharvesting: The harvesting of a renewable resource to the point of diminishing returns. * Over-hunting: Taking more individuals from a wild population than can be replaced by natural reproduction.

Definition: Habitat fragmentation occurs when large, continuous habitats are broken up into smaller, isolated areas or patches.
Historical Context: The lecturer notes that this process has split almost every forest in The US in the past.
Primary Causes: Habitat fragmentation is typically driven by human activity, specifically construction projects and infrastructure development.
Consequences: Large forests that species rely on are segmented, leading to isolated populations and reduced movement between habitat patches.

General Trends: While habitat loss is a recurring theme, climate change specifically impacts biodiversity by altering environmental conditions.
Geographic Variation: The impacts of climate change and warming are observed to be more intense in certain northern latitudes, causing specific environmental changes described as "orbs forming" or general warming trends.

Broadening the Definition of Biodiversity: Biodiversity is not limited solely to the variety of species (species diversity) found in the wild. It also includes: * Genetic diversity * Habitat diversity
The Role of Domestication: The domestication of animals has heavily affected the genetic diversity of modern fauna.
Artificial Selection: This is the process humans use in the domestication of farm animals to manipulate genetic traits. * Mechanism: A breeder or farmer selects specific individuals with desirable traits to reproduce. * Example: A chicken farmer identifies the "biggest, best chicken" and chooses it for reproduction to ensure the next series of chickens inherits those superior traits.

Mitigation: The lesson concludes with the goal of understanding how to mitigate (lessen the severity of) biodiversity loss.
Free Response Question (FRQ) Structure: The instructor outlines the specific constraints students face during the AP Environmental Science exam regarding FRQs: * The AP test includes a total of $3$ FRQs. * The total time allotted for the FRQ section is $1\,hour$ ( $60\,minutes$ ). * This mathematically allows for exactly $20\,minutes$ per FRQ. * Ideal Timing Strategy: The lecturer suggests students aim to complete each FRQ in $15\,minutes$ . This pace provides a total of $15\,minutes$ of extra time at the end of the exam to go back and check answers.
In-Class Exercise Guidelines: * Duration: Students are given exactly $20\,minutes$ to complete one FRQ. * Working Conditions: Students must work individually. The instructor monitors progress by walking around the room. * Resource Use: While the instructor prefers students work without notes to simulate exam conditions, they are permitted to use notes specifically to fill in "two blank" areas they may struggle with. * Self-Assessment: Following the exercise, an answer key is displayed on the screen for students to grade their own work.

Interaction on Animal Selection for Domestication: * Student: "It makes sense. You're not gonna pull up on a tiger and be like, good kid." * Student (Attempting to trace evolution): "Well, no. Wait. What did it have what did it have been like go from tiger to the house again." * Instructor: "No." * Student: "Wouldn't it have been like like a camel or something when or, like, when they use it, like, like a farm animal back in, like, the old times? Like, the horse? Or a horse." * Instructor: "It's always—Yeah. Like a horse. Like a camel. I don't know. A sheep." * Student: "Like sheep is not intimidating. I was all."
Discussion on Timing: * Student: "Wait. Does it take twenty minutes?" * Instructor: "On the AP test… you get three of them, and you gotta do them in an hour. So how long should it take you for each one? Fifteen minutes. Ideally… but, really, you got twenty minutes per FRQ."