Food Webs & Chains
What is the main source of energy for all food chains?
The Sun
What type of symbiotic relationship benefits one organism and doesn’t affect the other?
Commensalism
What is a limiting factor?
Anything that controls the size of a population (like food, space, or water).
What is an invasive species?
A non-native species that spreads and harms the ecosystem.
What is a primary consumer.
Eats the producer
What trophic level contains only autotrophs?
Producers
In parasitism, who is harmed?
The host
Name one biotic and one abiotic LIMITING factor.
Biotic – predators; Abiotic – temperature
There are other answer options!
How can an invasive species can harm an ecosystem?
It can outcompete native species for resources, causing native species to decline.
What do arrows in a food chain or food web represent?
The flow of energy
In a food web, a disease wipes out the primary consumers. Predict what might happen to the producer and secondary consumer populations.
Producer populations would increase due to less being eaten; secondary consumers may decrease due to lack of food.
A bird eats ticks off a buffalo’s back. The bird gets food, and the buffalo is cleaned of parasites. Identify the type of symbiosis and explain your reasoning.
Mutualism – both organisms benefit: food for the bird and parasite removal for the buffalo.
A population of rabbits increases rapidly in a forest. After several months, many begin to die off. What likely limiting factors caused this?
Food shortage, space limitations, or increased predation/disease due to overpopulation.
A fast-growing plant species introduced by humans spreads across wetlands, crowding out native plants. Predict one long-term ecological effect of this.
Loss of biodiversity as native species decline, which can affect animals dependent on those native plants.
Scientists observe a population decline in a species once considered stable. They review 10 years of climate data and predator activity. What type of evidence are they using and why is it valuable?
Empirical evidence – it helps identify patterns and test explanations over time using real-world data.
A new predator is introduced to a stable ecosystem. Explain how this could impact the food web.
It could cause population declines in prey species, disrupt balance, and impact other organisms that rely on the same prey.
An orchid grows on a tree trunk to access sunlight but doesn’t harm or help the tree. Predict what might happen if the tree is removed from the habitat.
The orchid loses its support and may die; the tree isn’t impacted, so its absence mostly affects the orchid.
During a drought, deer populations decline. Predict the long-term effect this drought could have on both predator and plant populations.
Predators may decline due to less food; plant populations may increase temporarily due to less grazing.
A lake is overrun by an invasive fish that eats the eggs of native fish. How might this affect the food web and future fish populations?
Native fish populations may crash, leading to collapse of the existing food web and a shift in predator/prey dynamics.
Researchers find a new fish species living near hydrothermal vents. How could this discovery change scientific explanations about life in extreme environments?
It may lead to updated models showing that sunlight isn’t necessary for all life and that chemical energy can support ecosystems.
Explain how decomposers are important to the environment.
They break down dead plants, animals, and waste, recycling nutrients back into the soil. This process keeps ecosystems clean and supports new plant growth by enriching the soil and maintaining the flow of energy.
A fungus grows on a plant’s roots, helping it absorb nutrients. However, if the fungus becomes too widespread, it starts taking more than it gives. How might this relationship shift, and what does this say about symbiotic relationships?
It could shift from mutualism to parasitism, showing symbiotic relationships can change depending on environmental conditions.
Two bird species use the same nesting area. One begins to push out the other over time. Explain how limiting factors and competition are interacting in this situation.
The nesting sites are a limiting factor; the more competitive species gains dominance, forcing the other to relocate or decline.
In an experiment, scientists find that a non-native insect outcompetes native insects for pollination. Suggest one reason this could be harmful for the ecosystem.
Native plants may go unpollinated if specialized to native insects, reducing reproduction and biodiversity.
Explain the graph.
As the invasive species was introduced, the native species decline.