Study Notes
Ecology and conservation focus on the interactions between species and their environments, and how these interactions affect biodiversity and ecosystem stability.
- Limiting factors — factors that restrict the growth, abundance, or distribution of an organism or a population of organisms in an ecosystem. Example: Light, temperature, and interactions between species.
- Ecological niche — the role and position a species has in its environment, including all interactions with biotic and abiotic factors. Example: A bird's niche includes its nesting area, diet, and predators.
- Keystone species — a species on which other species in an ecosystem largely depend, such that if it were removed the ecosystem would change drastically. Example: Sea otters maintain the balance of kelp forest ecosystems by preying on sea urchins.
- Trophic levels — the hierarchical levels in an ecosystem, comprising producers at the base and various levels of consumers. Example: Plants are producers, herbivores are primary consumers.
- Biomagnification — the process by which the concentration of toxic substances increases in each successive link in the food chain. Example: Mercury accumulation in fish.
- Primary succession — the series of community changes which occur on an entirely new habitat which has never been colonized before. Example: Colonization of a new volcanic island.
- Invasive species — non-native species that spread beyond their original introduction area and cause environmental or economic damage. Example: Kudzu vine in the United States.
Exam Tips
Key Definitions to Remember
- Limiting factors
- Ecological niche
- Keystone species
- Trophic levels
- Biomagnification
Common Confusions
- Difference between primary and secondary succession
- Distinction between bioaccumulation and biomagnification
Typical Exam Questions
- What is a keystone species? A species that has a disproportionately large effect on its environment relative to its abundance.
- How do invasive species affect ecosystems? They can outcompete native species, leading to reduced biodiversity.
- What is the role of producers in an ecosystem? They convert solar energy into chemical energy through photosynthesis, forming the base of the food chain.
What Examiners Usually Test
- Understanding of ecological niches and their importance
- The impact of human activities on ecosystems
- The role and significance of keystone species in maintaining ecosystem balance