Phylum Porifera: Sponges

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Questions and Answers

Which of the following is a characteristic feature of porifera that directly contributes to their filter-feeding lifestyle?

The presence of an endoskeleton composed of spicules and spongin fibres.
The absence of true tissues which allow individual cells to operate independently.
The presence of specialized collar cells or choanocytes lining the spongocoel. (correct)
The asymmetrical body plan, allowing for omnidirectional growth.

How does the intracellular digestion performed by porifera differ fundamentally from extracellular digestion seen in more complex animals?

Intracellular digestion involves enzymatic breakdown within cells, while extracellular digestion occurs outside of cells. (correct)
Intracellular digestion requires a more complex digestive system with specialized organs.
Intracellular digestion allows for the breakdown of a wider variety of food sources compared to extracellular digestion.
Intracellular digestion is less efficient in nutrient absorption compared to extracellular digestion.

How might the absence of true tissues in Porifera affect their response to environmental changes, compared to animals with true tissues?

Porifera are more adaptable to drastic temperature changes because individual cells can adjust independently.
Porifera may exhibit a slower and less coordinated response to stimuli due to the lack of integrated systems. (correct)
Porifera can regenerate damaged parts more efficiently because the absence of tissues simplifies the process.
Porifera can mount a more coordinated and rapid defense against pathogens due to the direct cell-to-cell communication.

What is the significance of the water canal system in Porifera, considering their sessile lifestyle?

It plays a crucial role in food gathering, gas exchange, and waste removal. (A) Signup and view all the answers

Given that Porifera lack true tissues and organs, how can they still coordinate activities such as contraction and expansion?

They depend on direct cell-to-cell communication and environmental cues. (D) Signup and view all the answers

How does the habitat of Spongilla differentiate it from the majority of other sponges, and what implications does this have for its physiology?

Spongilla lives in freshwater, necessitating osmoregulatory mechanisms not found in marine sponges. (A) Signup and view all the answers

Considering the asymmetrical body plan of Porifera, how might this characteristic impact their ability to adapt to directional environmental changes, such as altered water flow?

Their asymmetrical structure enables them to filter water from multiple directions simultaneously, enhancing their resilience to shifting currents. (C) Signup and view all the answers

What evolutionary advantage might the lack of germ layers provide to Porifera, considering their simple body plan and cellular-level organization?

It enables greater flexibility in cell differentiation and regeneration. (B) Signup and view all the answers

How does the process of indirect development in Porifera contribute to their dispersal and colonization of new habitats?

Indirect development produces a motile larval stage that facilitates dispersal over long distances. (A) Signup and view all the answers

In the context of Porifera reproduction, what is the functional significance of hermaphroditism (monoecious condition)?

It increases the likelihood of successful reproduction in sparsely populated environments. (C) Signup and view all the answers

Given that Porifera can reproduce both sexually and asexually, under what environmental conditions might asexual reproduction be more advantageous than sexual reproduction?

During periods of environmental stability and abundant resources. (B) Signup and view all the answers

What role do spicules and spongin fibers play in the structural integrity and defense mechanisms of Porifera?

They provide a rigid framework and deter potential predators. (B) Signup and view all the answers

How might the common name 'sponges' for Porifera mislead someone about their biological complexity?

The term belies their cellular-level organization and specialized cell types. (B) Signup and view all the answers

Given that the larva of Porifera is morphologically distinct from the adult form, what are the implications and benefits of this developmental strategy?

The larval form reduces competition with adults for resources. (A) Signup and view all the answers

Considering the role of collar cells in both trapping food particles and facilitating gas exchange, how does this dual function contribute to the overall efficiency of nutrient uptake and waste removal in Porifera?

It minimizes the energy expenditure required for separate nutrient acquisition and waste elimination processes. (B) Signup and view all the answers

How does the presence of ostia, spongocoel, and osculum in Porifera contribute to their osmoregulation and maintaining water balance, especially in freshwater species like Spongilla?

The structures facilitate rapid water intake and expulsion to counteract osmotic stress. (C) Signup and view all the answers

What implications does the cellular-level organization of Porifera have for their ability to repair injuries or regenerate lost body parts, compared to organisms with tissue-level organization?

They can regenerate faster because of the simple body plan. (A) Signup and view all the answers

Considering that Porifera are among the most primitive multicellular organisms, how might studying their cellular processes and interactions provide insights into the evolution of multicellularity in other animal groups?

Analysis of porifera can reveal the mechanisms and selective pressures that drove the emergence of complex tissues. (D) Signup and view all the answers

In what ways does the endoskeleton of Porifera differ structurally and functionally from the hydrostatic skeleton found in other invertebrates, such as annelids?

Porifera endoskeleton provides less flexibility. (B) Signup and view all the answers

How does the dependence on the water canal system limit the body size and shape of Porifera, and what evolutionary pressures might this impose?

The water canal system limits body size, where larger bodies would be inefficient. (D) Signup and view all the answers

Flashcards

Porifera reproduction

Both sexual and asexual reproduction through spore formation.

Porifera sexes

Sexes are united (monoecious or hermaphrodite) or (bisexual).