Symbiotic Relationships and Parasitism

These flashcards cover important concepts regarding symbiotic relationships, particularly focusing on parasitism, its ecological significance, types, adaptations, and its consequences on host populations and ecosystems.

What is the definition of symbiosis?

An intimate association between two organisms where one is the host and the other is the symbiont.

What type of symbiosis occurs when one organism benefits without harming the other?

Commensalism.

What is mutualism?

A type of symbiosis where both organisms derive benefits from the association.

What key evolutionary event is an example of mutualism?

The origin of the eukaryotic cell through bacterial symbiosis.

Define parasitism.

A type of symbiosis where the symbiont benefits while causing harm to the host.

What constitutes the symbiosis continuum?

The range from mutualism to commensalism to parasitism.

What percentage of animal species utilize parasitism?

Over 50%.

Why is studying parasitism important?

It helps understand causes of diseases, biological control, evolution, ecosystem stability, and conservation.

Name a type of worm that is a parasite.

Platyhelminthes, which includes trematodes and cestodes.

What are trematodes?

Endoparasites in vertebrates also known as flukes.

Define nematodes.

Roundworms that can be endoparasites in either vertebrates or invertebrates.

What is the significance of complex life cycles in parasites?

They provide protection, access to resources, and easier routes to definitive hosts.

What is a definitive host?

The host where adult parasites live and reproduce sexually.

How do parasites transmit to their hosts?

Through various methods, including predation and specialized infection mechanisms.

What is a paratenic host?

A transport host where the parasite does not develop.

What evolutionary trend is observed in parasitism?

Parasitism has evolved independently over 200 times in the animal kingdom.

What adaptations do parasites develop against host defenses?

Chemical disguises, surface turnover, and immunosuppression.

How can grooming help a host?

It can remove ectoparasites.

What does egg hatching timing influence in parasites?

It is crucial for successful infection of the right host.

What adaptations assist nematodes in surviving environmental stresses?

Their eggs can resist desiccation and hatch based on host gut conditions.

What negative effects do parasites tend to exert on their hosts?

Reduced growth, survival, and fecundity.

What is one laboratory experiment demonstrating the impact of parasites on host populations?

Beetles infected by cestode larvae show adverse effects compared to uninfected beetles.

How can parasites alter competition among host species?

By shifting the competitive balance, affecting outcomes based on the presence of parasites.

What impact did malaria introduction have on Hawaiian bird populations?

Native Hawaiian birds experienced population declines due to high susceptibility.

What link has been established concerning global amphibian extinctions?

Chytrid fungus has been linked to these extinctions.

Describe the ecological significance of trematodes in Otago Harbour mudflats.

They influence host populations, affect biodiversity, and stabilize food webs.

What is one impact of trematode parasitism on snails?

Complete castration of the snail hosts.

What cascading effects do parasites have on ecosystems?

Effects on one host population lead to ecological changes throughout the community.

What role do parasites play in regulating host populations?

They can dampen population fluctuations leading to stable numbers.

What is the interaction trend between parasites and host behavior?

Some parasites manipulate host behavior for their own benefit.

What does the term coevolution mean in the context of parasites?

The simultaneous evolution of parasites and their hosts affecting each other's adaptations.

Name a defense mechanism hosts utilize against parasites.

The immune system.

What is the result of parasite-induced alterations in host behavior?

Increased predation risk or altered survival strategies.

How do parasites ensure their transmission through predation?

They can manipulate host behavior to increase likelihood of being consumed by predators.

What are examples of ectoparasites?

Fleas and lice.

What is a typical consequence of high worm burden in hosts?

Anemia and reduced overall health.

How do parasites contribute to biodiversity?

By enhancing population dynamics and interactions within ecosystems.

What strategies do parasites use to enhance their chances of finding hosts?

Chemical signals or host-manipulation tactics.

What is the ecological impact of parasites on sediment communities in Otago?

Increased biodiversity and stabilization of food webs.

Name one type of arthropod parasite.

Mites or ticks.

How do parasites typically interact with their ecosystems?

They influence community structuring and energy flow.

What resemblance is seen between different phyla of parasites?

Convergent evolution resulting in similar adaptations.

How frequently does parasitism emerge in the animal kingdom?

More than 200 independent occurrences.

List one example of a well-studied protozoan parasite.

Malaria.

What role do parasites play in wildlife management?

They are integrated into conservation strategies to preserve species and habitats.

What can parasite-induced changes to host populations lead to?

Altered community dynamics, affecting the entire ecosystem.

What type of parasite is known to impact crab behavior significantly?

Acanthocephalans.

What is one potential positive role of parasites in ecosystems?

They can contribute to overall biodiversity and community health.

What is one major characteristic of parasitic organisms?

Total dependence on the host for survival and reproduction.

Name a method by which parasites enhance egg transmission in hosts.

Timing hatching to coincide with the host's availability.

What effects do parasites have on food webs?

They create complex interactions that regulate population dynamics.

How can host immunity affect parasites?

Hosts with strong immunity can limit parasite success and survival.

What do parasites often exploit in their life cycles?

Dynamic predator-prey relationships.