Bio 2nd

Distribution of Organisms

• 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

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

Biotic Relationships

• 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.

Feeding Relationships

• 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.

Impact of Removing Species

• 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 Impact on Biodiversity

• 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

• 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.

Impact of Human Activities

• 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.