Design, evaluate, and refine a solution for reducing the adverse impacts of human activity on the environment and biodiversity (Louisiana Student Standards for Science, High School Biology, HS-LS2-7).

What this topic is asking

Louisiana's LS2 standards (HS-LS2-7) ask you to design, evaluate, and refine a solution for reducing the adverse impacts of human activity on the environment and biodiversity. For LEAP 2025 Biology you should know the main human impacts (habitat loss, pollution, climate change, invasive species, overexploitation), be able to propose a solution to a given problem, and explain how you would evaluate whether it works. This is a designing-solutions standard, so the test rewards a sensible solution plus a way to measure its success.

How humans affect ecosystems

The main impacts the test expects you to recognize are:

• Habitat destruction. Clearing forests, draining wetlands, and urban development remove the places organisms live, the leading cause of biodiversity loss.
• Pollution. Chemicals, plastics, and especially fertilizer runoff that causes excessive algae growth (which can remove oxygen from water and kill aquatic life).
• Climate change. Greenhouse gases (largely from burning fossil fuels) warm the planet and shift where species can survive.
• Invasive species. Species introduced to a new area can outcompete natives that have no defenses against them.
• Overexploitation. Overfishing, overhunting, and overharvesting remove species faster than they can reproduce.

Why this matters: linking back to stability

Because all of these impacts reduce biodiversity, they make ecosystems less stable and resilient (the connection to the previous topic). An ecosystem with fewer species and less genetic variety is more vulnerable to further disturbance, so human impacts can set off a downward spiral. This is the reasoning behind conservation.

Designing a solution

Evaluating and refining the solution

A solution is not complete until you can tell whether it works. To evaluate it, you measure an outcome over time: for a pollution problem, monitor the nutrient or algae levels in the water; for a habitat project, track the recovery of species or the area of habitat restored. If the data show the problem is not improving, you refine the solution (adjust it, scale it up, or try another approach). This design, evaluate, refine cycle is exactly what the standard rewards.

Try this

Q1. Name three ways human activity reduces biodiversity. [2]

• Cue. Any three of: habitat destruction, pollution, climate change, invasive species, overexploitation.

Q2. Propose a solution to reduce habitat loss and state how you would evaluate its success. [2]

• Cue. Solution: protect or restore habitat (such as a protected area or replanting native vegetation). Evaluation: measure the area of habitat protected or restored and monitor the recovery of species over time.