Topic 9 Ecosystems and Material Cycles Flashcards
What is an ecosystem?
An ecosystem is a community of living organisms (biotic factors) interacting with their physical environment (abiotic factors).
What is meant by the term “interdependence” in an ecosystem?
Interdependence refers to the reliance of organisms on each other for food, shelter, pollination, seed dispersal, and other needs for survival.
What is a population in terms of an ecosystem?
A population is a group of individuals of the same species living in a specific area.
What is the difference between a habitat and a niche?
A habitat is the physical environment where an organism lives, while a niche is the role and position an organism has in its environment, including its interactions with other species.
What is meant by “biotic factors” in an ecosystem? Give an example
Biotic factors are living components of an ecosystem, such as plants, animals, and bacteria. An example is predation.
What is a food chain?
A food chain is a linear sequence showing how energy and nutrients flow from one organism to another in an ecosystem.
What is the role of producers in a food chain?
Producers, like plants and algae, make their own food through photosynthesis and provide energy for the rest of the food chain.
What are primary consumers, and what do they eat?
Primary consumers are herbivores that eat producers (plants).
What is the difference between a food chain and a food web?
A food chain shows a single path of energy flow, while a food web shows the interconnected feeding relationships in an ecosystem.
Why is energy lost at each trophic level in a food chain?
Energy is lost at each trophic level due to processes like respiration, movement, and heat production, as well as waste products (undigested material).
What is a predator-prey relationship?
It is an interaction where a predator hunts and kills prey for food, helping regulate population sizes in an ecosystem.
What is competition in an ecosystem?
Competition occurs when organisms vie for the same resources, such as food, water, shelter, or mates, within a habitat.
What is interspecific competition?
Competition between different species for the same resources.
What is intraspecific competition?
Competition between individuals of the same species for resources.
How can an increase in prey population affect predator numbers?
An increase in prey population can provide more food for predators, leading to an increase in predator numbers.
What are the main processes involved in the carbon cycle?
Photosynthesis, respiration, combustion, and decomposition.
How does photosynthesis contribute to the carbon cycle?
Plants take in carbon dioxide from the atmosphere and use it to make glucose during photosynthesis, locking carbon in organic molecules.
How does respiration affect the carbon cycle?
Respiration by plants, animals, and decomposers releases carbon dioxide back into the atmosphere.
What role do decomposers play in the carbon cycle?
Decomposers break down dead organisms, returning carbon to the soil and releasing carbon dioxide into the atmosphere through respiration.
How does combustion of fossil fuels affect the carbon cycle?
Burning fossil fuels releases large amounts of carbon dioxide into the atmosphere, contributing to the greenhouse effect and global warming.
Why is nitrogen important for living organisms?
Nitrogen is needed to make proteins and DNA, which are essential for growth and reproduction.
What is nitrogen fixation, and which organisms are involved?
Nitrogen fixation is the process by which nitrogen gas from the atmosphere is converted into ammonia or nitrates. Nitrogen-fixing bacteria in soil or root nodules of legumes perform this task.
What is the role of nitrifying bacteria in the nitrogen cycle?
Nitrifying bacteria convert ammonia into nitrites and then nitrates, which plants can absorb.
What is the role of denitrifying bacteria in the nitrogen cycle?
Denitrifying bacteria convert nitrates back into nitrogen gas, releasing it into the atmosphere.
