Ecology and Environmental Science Lecture Notes

These flashcards cover key concepts from ecology and environmental science, including ecological niches, competition, mutualism, and energy flow through ecosystems.

What is an ecological niche?

An ecological niche is the role and position a species has in its environment, including all the interactions it has with biotic and abiotic factors.

What is niche overlap?

Niche overlap occurs when two species share a portion of their niches, leading to competition for resources.

When does the greatest competition between two species occur?

The greatest competition occurs when two species have overlapping niches.

How is competition defined?

Competition is defined as the interaction between organisms or species in which both are harmed while competing for limited resources.

What are different species competing for?

Species compete for resources such as food, space, light, and mates.

What is the difference between intraspecific competition and interspecific competition?

Intraspecific competition is competition between members of the same species, while interspecific competition is competition between different species.

What is the difference between asymmetric competition and symmetric competition?

Asymmetric competition occurs when one species is more adversely affected than another, whereas symmetric competition affects both species equally.

Which is more common in nature, symmetric or asymmetric competition?

Asymmetric competition is more common in nature.

Does competition always involve direct contact or fighting?

No, competition can occur without direct contact, such as through resource depletion.

What is competitive exclusion? When does it occur?

Competitive exclusion is the principle stating that two species competing for the same resource cannot coexist if other ecological factors are constant; it occurs when one species outcompetes the other.

What is the intertidal zone?

The intertidal zone is the area of the shoreline that is covered by water at high tide and exposed to air at low tide.

What did ecologist Joe Connell notice about two species of barnacle in the intertidal zone?

Connell observed that one species of barnacle was able to thrive in different areas of the intertidal zone while another was limited to a narrower band.

How do barnacles feed?

Barnacles are filter feeders, feeding by filtering plankton and other particles from the water.

What experiment did Connell do?

Connell conducted an experiment to test the hypotheses of competition and ecological niche to see how barnacle species coexisted in the intertidal zone by removing one species and observing the results.

What is the fundamental niche of a species?

The fundamental niche is the potential mode of existence of a species, representing the full range of conditions under which a species can survive and reproduce.

What is the realized niche of a species?

The realized niche is the actual conditions in which a species exists, taking into account biotic interactions like competition.

Which is usually bigger: the fundamental niche or the realized niche?

The fundamental niche is usually bigger than the realized niche.

What is mutualism?

Mutualism is a type of interaction where both species involved benefit from the relationship.

What are Rhizobium bacteria?

Rhizobium bacteria are a type of bacteria that live in symbiosis with legumes, fixing nitrogen in the soil.

What are mycorrhizal fungi?

Mycorrhizal fungi are fungi that form beneficial relationships with the roots of plants and help them absorb water and nutrients.

What is coevolution?

Coevolution is the process by which two or more species influence each other's evolution.

What is the impact of mutualisms on land plants?

Mutualisms can enhance nutrient absorption, growth, and viability of land plants.

What is a trophic cascade?

A trophic cascade is an ecological phenomenon triggered by the addition or removal of top predators, leading to changes in the structure and functioning of the ecosystem.

What happens to the energy in a top predator when it dies?

When a top predator dies, its energy can be decomposed and returned to the ecosystem, but is not used by primary producers directly.

What is a limiting nutrient?

A limiting nutrient is a nutrient that is in short supply and limits the growth of organisms in an ecosystem.

What is nitrogen fixation?

Nitrogen fixation is the process by which nitrogen gas in the atmosphere is converted into ammonia by certain bacteria.

What is meant by saying energy flows but matter cycles?

This means that energy moves through the ecosystem in a one-way flow, while matter is recycled and reused within the ecosystem.