1. What is a sustainable ecosystem? (C)
➡ A sustainable ecosystem is one that can maintain its health, biodiversity, and productivity over time, even while supporting living things, including humans.

2. Draw a flowchart showing how the collapse of the forest ecosystem on Easter Island affected humans. (K/U)
Here’s a simple flowchart in words (I can also make a visual if you want):

nginx

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Deforestation → Loss of trees → Soil erosion → Poor crops → Food shortage → Starvation → Population decline

3. Identify and describe three abiotic characteristics of ecosystems. Give an example of how each could be affected by human activity. (C)

Water: Essential for all life. ➡ Pollution from factories can contaminate water.
Temperature: Affects species survival. ➡ Climate change from burning fossil fuels raises temperatures.
Soil quality: Needed for plants to grow. ➡ Overuse of pesticides can degrade soil health.

4. Draw the nitrogen cycle. Explain the role of bacteria. (C)
➡ Quick explanation:
Bacteria convert nitrogen gas from the air into forms plants can use (nitrification). Other bacteria help return nitrogen back to the atmosphere (denitrification).
(I can also draw a diagram if you want!)

5. Phosphorus cycle and humans (C)
a. How can human activities affect the phosphorus cycle?
➡ Using fertilizers adds too much phosphorus to soil and water, leading to water pollution and algae blooms.

b. How can eutrophication be avoided?
➡ By using less fertilizer, planting buffer plants near water, and controlling waste from farms and factories.

6. How can scientific research influence society to push for change? (T/I)
➡ Scientific research shows evidence of problems (like pollution or climate change), helping governments and people understand why action is needed. Example: research on DDT led to banning the pesticide.

7. Positive actions to reduce nutrient pollution (A)

Farmers: Use natural fertilizers and plant cover crops.
Fertilizer companies: Make eco-friendly products.
Governments: Create and enforce environmental laws.
Consumers: Buy sustainably grown food.

8. Phosphorus levels in Lake Erie (A)
➡ (Based on the description — since I can’t see the graph):
Over the last 30 years, phosphorus levels have likely decreased (thanks to better pollution control) but might show small increases at times due to runoff or farming.

Section 1.2 Review

1. Explain the process of photosynthesis. (K/U)
➡ Plants use sunlight, carbon dioxide (CO₂), and water (H₂O) to make sugar (energy) and oxygen (O₂).

2. What three chemical elements are the building blocks of carbohydrates? (K/U)
➡ Carbon (C), Hydrogen (H), and Oxygen (O).

3. Should photosynthesis win “Most Important Chemical Reaction”? (C)
➡ Yes, because it creates oxygen for breathing and food for almost all life on Earth!

4. Difference between producer and consumer? (K/U)

Producer: Makes its own food (like plants).
Consumer: Eats other organisms for energy (like animals).

6. What happens to energy that doesn’t move up? (K/U)
➡ It’s lost as heat, waste, or used up in life activities (like movement and breathing).

7. Venn diagram comparing bioaccumulation and biomagnification (C)
Bioaccumulation: Toxins build up in one organism over time.
Biomagnification: Toxins increase at each food chain level.
Both: Involve harmful chemicals and affect living things.

Example bioaccumulation: Mercury in a fish.
Example biomagnification: Mercury levels highest in a large predator like a shark.

8. Lake with leaking chemicals (T/I)
➡ Larger fish would have higher chemical levels because they eat many smaller fish, each with some toxins. (This is biomagnification.)

Ecology is the study of interactions between organisms and their environment.
Ecosystem Types:
- Terrestrial: On land (e.g., forests).
- Aquatic: In water (e.g., oceans, coral reefs).
Factors:
- Biotic: Living (e.g., algae, sharks).
- Abiotic: Non-living (e.g., rocks, water).
Symbiotic Relationships:
- Mutualism: Both benefit (e.g., alligator and bird).
- Predation: One eats the other (e.g., predator-prey).
- Competition: Both want the same resource (e.g., food).
Biotic-Abiotic Interactions:
- Dry seasons can harm plants and animals (water).
- Pollution can suffocate fish (oxygen).
- Soil erosion can hinder plant growth (soil).
Sustainable Ecosystems:
- Maintain ecological balance over time (resources, biodiversity).
- Sustainability is crucial for ecological health.
Cycle of Matter:
- Limited resources must be recycled for sustainability.
Earth's Spheres:
- Lithosphere: Earth's solid surface.
- Hydrosphere: All earth's water.
- Atmosphere: Gases above earth's surface.
- Biosphere: Areas where life exists.
Carbon Cycle:
- Photosynthesis: CO₂ to sugar.
- Cellular Respiration: Sugar to CO₂.
- Decomposition: Breaks down matter.
- Extraction: Mining fossil fuels.
Food Webs:
- Start with producers (plants).
- Consumers: eat plants/other animals.
- Decomposers: break down organic matter (e.g., fungi).
- Scavengers: eat remains of dead animals (e.g., vultures).
Important Processes:
- Photosynthesis: CO₂ + H₂O + light energy = sugar + O₂
Ecosystem Impact:
- What happens if we remove/add something to an ecosystem affects balance and productivity.

#6 This ecosystem shows top-down regulation.

That means the lynx (predators) are controlling the number of hares.
When there are lots of hares, lynx have lots to eat, so their numbers go up.
Then the lynx eat too many hares, so the hare numbers go down.
Then the lynx don’t have enough food, so they go down too.
Then the cycle starts again.

The shrubs aren’t the problem, so it's not bottom-up — it's all about the lynx eating the hares.

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Mutualism – When two living things help each other
Population – A group of the same kind of animal or plant living in one place
Niche – Everything a living thing needs to survive (like food, shelter, and space)
Carrying capacity – The biggest number of animals or plants an area can support forever
Symbiont – A small living thing that depends on a bigger one
Ecological footprint – How much a person or group affects nature (like how much land, water, and energy they use)
Ecological connectivity – How different ecosystems are connected, even if they’re far apart
a. Polar bear – Needs ice to hunt.
b. Hibernating bat – Needs a cave or safe place to sleep.
c. Tree swallow – Needs a nesting spot like a hole in a tree.

15. They help control insect populations, which keeps the environment balanced and helps

Eutrophication - extra nutrients leads to increase in number of producers

Dramatic increase in algae population

When algae die decomposition occurs and all the oxygen is used up

Organisms such as fish die because of the lack of oxygen

May 2 2025

Ecoligy lesson 4

Polution

Bioaccumulation - when matierias (mostly toxins) are ingested by organisms at a rate that is faster then they can be eliminated

Biomagnification - when the concentration of ingested toxins increases as you move up trophoc levels.

Ex mercury levels in minnows vs tuna DDT and PCS’s are examples of toxins that get into the soil/water and are highly stable and toxic. The concentrations of these toxins are much higher in animals at the top of the food chain than at the bottom, leading to may negative effects.

Biodiversity

Higher biodiversity leads to better sustainability

Measuring biodiversity 4 ways

Method depends on what type of ecosystem is being measured

Canopy fogging - primarily used to identify/count insects

Low dose of insecticide is sprayed into trees and the insects fall down, are caught, counted and identified.

Quadrat sampling - for plants and animals

A space is divided into quadrants, (size of quadrant depends on overall space)
Species of plants and animals are counted in varius quadrants and average is found and applied to the overall habitat.

Transect sampling - often used in aquatic environments EX: coral reef