Species Interactions: Section 5.2

Questions and Answers

What is an organism's niche?

Describes an organism's use of resources and functional role in a community.

What is included in an organism's niche?

Where an organism lives, food, when they reproduce, what organisms they interact with.

What is an organism's niche affected by?

An organism's tolerance—the ability to survive and reproduce under changing environmental conditions.

What restricts an organism's niche?

Often restricted by competition (intraspecific - same species; interspecific - different species). Signup and view all the answers

What is Competitive Exclusion?

Where one species excludes another species from using a resource entirely. Signup and view all the answers

What is an example of Competitive Exclusion?

Zebra mussels attach to native bivalve species, so they starve or suffocate. Signup and view all the answers

What kind of niche can an organism use without competitors?

Without competitors, an organism can use its entire fundamental niche. Signup and view all the answers

What can happen to an organism's niche if limited by competitors?

Competitors can limit an organism to a realized niche, or a portion of what an organism can do and what resources it can use. Signup and view all the answers

Why is Resource Partitioning used in a community?

To reduce competition, species often partition resources, which can lead to character displacement—a specialized role in the environment. Signup and view all the answers

What is predation?

The process by which a predator hunts, kills, and consumes prey. Signup and view all the answers

What does predation cause?

Causes cycles in predatory and prey population sizes. Signup and view all the answers

What evolves in an organism in response to predator/prey interactions?

Defensive traits such as camouflage, mimicry, and warning coloration. Signup and view all the answers

Who has a positive benefit and who has a negative benefit from predation?

The predator has positive effects, while the prey has negative effects. Signup and view all the answers

What is Coevolution of predator/prey?

The process by which two species evolve in response to changes in each other. Signup and view all the answers

What is Herbivory?

When an animal feeds on a plant (herbivore). Signup and view all the answers

What kind of defense mechanisms have plants evolved to defend themselves?

Plants have evolved defenses such as toxic or distasteful chemicals, thorns, spines, etc. Signup and view all the answers

Explain Symbiosis.

"Living together" - a long-lasting and physically close relationship in which one organism benefits. Signup and view all the answers

What is Parasitism?

When one organism (the parasite) relies on another (the host) for nourishment or for some other benefit. Signup and view all the answers

Who has a positive benefit and who has a negative benefit from parasitism?

The parasite benefits positively, while the host experiences negative effects. Signup and view all the answers

What is Mutualism?

A relationship in which two or more species benefit. Signup and view all the answers

What is an example of Mutualism?

Lichen: a symbiotic relationship between a fungus and a photosynthetic partner, such as an alga. Signup and view all the answers

Who benefits from Mutualism?

Both organisms benefit and are positively affected. Signup and view all the answers

What is Commensalism?

A relationship in which one species benefits while the other is unaffected. Signup and view all the answers

Study Notes

Organism's Niche

An organism's niche encompasses its resource utilization and functional role within a community.
Key aspects of a niche include habitat, food sources, reproductive periods, and interactions with other organisms.
The tolerance of an organism influences its niche, determining survival and reproduction abilities in varying environments.
Competition, both intraspecific (within species) and interspecific (between species), often limits an organism's niche.

Competitive Exclusion

Competitive exclusion occurs when one species entirely denies another species access to a resource.
An example includes zebra mussels outcompeting native bivalve species, leading to their starvation or suffocation.
In the absence of competitors, an organism can fully utilize its fundamental niche.
Competition can reduce an organism to a realized niche, restricting its access to resources.

Resource Partitioning

Resource partitioning helps reduce competition by dividing resources among species, potentially resulting in character displacement, where species adopt specialized roles.

Predation

Predation involves a predator hunting, killing, and consuming its prey.
This process creates cyclical population dynamics between predators and prey.
Defensive adaptations in prey species include camouflage, mimicry, and warning coloration, evolving in direct response to predation pressures.
Predators benefit from predation as a food source, while prey experience negative consequences, often leading to death.

Coevolution

Coevolution describes the mutual evolutionary influences between predator and prey species, such as Newts developing toxins and Garter snakes evolving tougher skin to survive.

Herbivory

Herbivory is defined as the consumption of plants by animals, leading to evolutionary pressures on plant defenses.

Plant Defense Mechanisms

Plants have developed various defensive strategies, including toxic chemicals, distastefulness, thorns, and spines to deter herbivores.

Symbiosis

Symbiosis signifies a long-term, close relationship where at least one organism benefits from the interaction.

Types of Symbiotic Relationships

Parasitism: One organism (the parasite) derives benefit at the expense of another (the host), causing harm to the host while the parasite benefits.
Mutualism: A symbiotic relationship where both species involved reap benefits, exemplified by lichen, which consists of a fungus and a photosynthetic algae.
Commensalism: A relationship where one species benefits while the other remains unaffected, such as a fish benefiting from residing near a sea anemone.

Benefits in Symbiotic Relationships

In parasitism, the parasite enjoys positive effects while the host suffers negative effects.
In mutualism, both species benefit, leading to positive mutual effects.

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Description

Test your knowledge on the concepts of ecological niches in this quiz. Understand the various components that constitute an organism's niche, including habitat, food sources, and reproductive behaviors. Explore how these factors interact with species tolerance and overall community dynamics.