IB ESS - Topic 2 Ecology Study Notes

IB ESS - Topic 2 Ecology

Ecology Term & Study Sheet
2.1 Species and Populations (read pp. 104-116 & 124)

1. Scientific Naming Conventions (Taxonomy)

  • Definition: Taxonomy ranks organisms from general to specific.
  • Hierarchy of Taxonomic Ranks:
    • Kingdom
    • Phylum
    • Class
    • Order
    • Family
    • Genus
    • Species

2. Genus

  • Definition: A taxonomic rank below family and above species.

3. Species

  • Definition: A group of living organisms that can interbreed with one another in nature to produce fertile offspring.

4. Subspecies

  • Definition: A distinct population within a species that shares core characteristics that differentiate them from others of the same species.

5. Population

  • Definition: The total number of inhabitants in a specific area.

6. Habitat

  • Definition: The natural environment where an organism or species lives.

7. Fundamental Niche

  • Definition: The full, ideal range of resources and conditions, including food, water, shelter, and temperature, that an organism could use to survive and reproduce, assuming there are no predators or competitors.

8. Realized Niche

  • Definition: The actual habitat, resources, and conditions that organisms use in an ecosystem.

9. Population Dynamics

  • Definition: The study of how and why populations change in size, structure, and distribution over time.
  • Drivers of Change: Changes are driven by births, deaths, immigration, and emigration (migration).

10. Predation

  • Definition: The act of preying on another being.
  • Roles:
    • Predator: Organism that hunts and kills prey.
    • Prey: Organism that is hunted and killed.

11. Herbivore

  • Definition: An organism that solely eats/gains energy by consuming plants and organic material.
  • Diet Restrictions: Herbivores do not consume meat.

12. Symbiotic Relationships

  • Definition: Interactions between two different species living in close physical proximity.
  • Types of Symbiotic Relationships:
    • a) Parasitism: One species benefits while the other suffers.
    • b) Mutualism: Both species benefit from the interaction.
    • c) Commensalism: One species benefits and the other is unaffected or remains neutral.

13. S-Curves

  • Definition: A graphical representation showing a pattern of population growth that starts slowly, accelerates rapidly, and then gradually slows down as it levels off and saturates.

14. J-Curves

  • Definition: A pattern characterized by an initial decline followed by a substantial recovery in population.

15. Carrying Capacity

  • Definition: The maximum population size that an environment can sustain indefinitely without degrading the environment.

16. Environmental Resistance

  • Definition: Factors that limit a population’s growth, preventing it from reaching its full potential.

17. Diebacks (Overshoots)

  • Definition: A cycle of unsustainable growth followed by a sudden, often catastrophic decline in population size.
  • Overshoot Explanation: An overshoot occurs when the population, consumption rate, or environmental stressor exceeds the carrying capacity of its environment.