Bio 2nd

Study Notes

Distribution refers to where organisms can be found; for example, penguins are primarily located in the Arctic.
Organism distribution is influenced by both abiotic (non-living) factors and biotic (living) factors.

Biotic factors include living components of ecosystems that affect organism distribution, such as:
- Disease
- Predation
- Food availability
- Competition

Biotic relationships involve interactions between living organisms, categorized under symbiosis.
Symbiosis is classified based on the benefits to the organisms involved.
- Mutualism: Both species benefit (e.g., clownfish and anemone).
- Example: Clownfish receive shelter while providing food/nutrients to the anemone.
- Example: Pollinators (like bees) help plants reproduce while obtaining nectar.

Organisms store energy in the form of food, which is critical for survival.
A food chain illustrates who eats whom in a habitat, indicating the direction of energy flow:
- Example: Sun → Oak Tree → Wood Mouse → Weasel → Owl
Producers are organisms that create their own food, typically green plants.
Primary consumers (herbivores) obtain energy directly from plants.
Secondary consumers are carnivores that eat primary consumers (e.g., weasel and owl).
Tertiary consumers are top predators in a food chain.
Food webs connect multiple food chains to show interconnected feeding relationships.

Removing a single organism from a food web can harm the entire ecosystem, especially due to factors like pesticides, habitat alteration, and climate change.

Human population growth is driven by:
- Industrialization, leading to increased wealth.
- Improved food production resulting in higher birth rates and survival.
Greater human population results in:
- Increased demand for land for agriculture and housing.
- Over-hunting of species and habitat destruction.

Biodiversity encompasses the variety of all living things and includes:
- The range of species present in an ecosystem.
- Variations within species that allow them to adapt and survive.

Fertilizers: Used to enhance food crop production but can pollute waterways, leading to algal blooms that deplete oxygen and harm marine life.
Pesticides: Aimed at controlling pests but may inadvertently kill non-target organisms, affecting the food chain and ecosystem balance.

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