Questions and Answers
What is a rotifer?
What are rotifers also known as?
Wheel animals
What size of organism do rotifers mainly prey on?
Microscopic organisms
What is the most noticeable part of a rotifer's anatomy?
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What is the trophi in a rotifer's neck?
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What is the function of the trunk in rotifers?
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What is the role of the foot in rotifers?
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On what kind of animals are rotifers most likely to be found?
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What does the term planktonic refer to?
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What is the most common method of reproduction among rotifers?
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How long does it usually take for rotifer eggs to hatch?
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What common trait do many microscopic animals share?
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How do bdelloid rotifers reproduce?
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What is a defining characteristic of bdelloid rotifers?
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What structure in rotifers guides food particles into their mouths?
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From what does the phylum name Rotifera derive?
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Where does digestion and absorption of food occur in rotifers?
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Which part of the rotifer is the only one that can fossilize?
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Why do some rotifers reproduce primarily through asexual means?
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Study Notes
Overview of Rotifera
- Rotifers are small aquatic invertebrates, averaging 50 micrometers to over 2 millimeters in size, characterized by a ring of cilia around the mouth that resembles a spinning wheel.
- Commonly referred to as "wheel animals" due to their distinct head structure known as the corona, which aids in locomotion and feeding.
Anatomy of Rotifers
- Head: Features a semicircular, wheel-like appearance covered with cilia that assist in digestion and sensory functions. The cilia collectively referred to as the corona, resemble a crown.
- Neck: Contains the trophi, the only rigid part of the rotifer's body, which can fossilize when replaced by minerals post-mortem.
- Trunk: A tube-like, extendable body made of concentric tubular portions for flexibility and movement, covered by a transparent cuticle.
- Foot: Used for propulsion and attaching to surfaces, essential for rotifers that form colonies for survival; over twenty species live in colonies.
Habitat and Diet
- Rotifers primarily inhabit aquatic environments and can be found as parasites on other aquatic animals.
- They predominantly feed on microscopic organisms, aligning their size and hunting strategy with their prey.
Reproduction and Development
- Reproduction: Primarily through parthenogenesis (asexual) where embryos develop without fertilization; both male and female forms exist, but males are rare or not observed in many species.
- Embryo Development: Eggs can be carried externally or internally, hatching typically within 12 hours, with development stages influenced by environmental factors.
- Adult Life Span: Generally short, ranging from 5 to 45 days, with their eggs and adults being preyed upon by various organisms.
Specific Class: Bdelloid Rotifers
- Comprising 450 species, bdelloid rotifers are resilient and primarily found in freshwater, feeding on bacteria and algae.
- Known for unique survival mechanisms, they undergo anhidrosis to withstand dry conditions by dehydrating and entering a dormant state until moisture returns.
Key Biological Processes
- Cilia are crucial for guiding food to the rotifer's mouth and aiding in efficient feeding.
- Digestion and absorption mainly occur in the stomach, where food is processed after being gathered by cilia.
- The trophi structure is the only part of a rotifer that can become fossilized, highlighting its significance in paleontological studies.
Notes on Life Cycle
- Many microscopic animals, including rotifers, exhibit short life cycles, a common trait that enhances species survival in fluctuating environments.
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Description
Test your knowledge of Phylum Rotifera with these flashcards! Each card presents a term related to rotifers, including definitions and interesting facts about their size and feeding habits. Perfect for students and enthusiasts of aquatic biology!
