Unlike an earthworm's metanephridia, a mammalian nephron a. is intimately associated with a capillary network. b. functions in both osmoregulation and excretion. c. receives filtrate from blood instead of coelomic fluid. d. has a transport epithelium.

Verified step by step guidance

1. Step 1: Understand the question. The question is asking for the difference between an earthworm's metanephridia and a mammalian nephron.
2. Step 2: Recall what you know about earthworm's metanephridia and mammalian nephrons. Metanephridia are excretory organs in earthworms that filter waste from the coelomic fluid. Mammalian nephrons, on the other hand, are part of the kidney and filter waste from the blood.
3. Step 3: Evaluate each option. Option a is true, mammalian nephrons are associated with a capillary network. Option b is also true, mammalian nephrons function in both osmoregulation and excretion. Option d is true as well, mammalian nephrons have a transport epithelium.
4. Step 4: The correct answer is option c. Unlike an earthworm's metanephridia, a mammalian nephron receives filtrate from blood instead of coelomic fluid. This is the key difference between the two.
5. Step 5: Review the answer. The mammalian nephron, unlike the earthworm's metanephridia, is associated with a capillary network, functions in both osmoregulation and excretion, has a transport epithelium, and receives filtrate from blood instead of coelomic fluid.

Key Concepts

Nephron Structure and Function

The nephron is the functional unit of the kidney in mammals, responsible for filtering blood and forming urine. It consists of a renal corpuscle and a renal tubule, which work together to remove waste products and regulate water and electrolyte balance. Understanding the nephron's structure is crucial for distinguishing its functions from those of other excretory systems, such as the metanephridia in earthworms.

Osmoregulation

Osmoregulation is the process by which organisms maintain the balance of water and solutes in their bodies. In mammals, the nephron plays a key role in osmoregulation by adjusting the concentration of urine based on the body's hydration status. This process is vital for homeostasis, ensuring that cells function optimally despite varying external conditions.

Filtration Mechanism

The filtration mechanism in the nephron involves the glomerulus, a network of capillaries where blood is filtered to form filtrate. Unlike metanephridia, which filter coelomic fluid, mammalian nephrons filter blood directly, allowing for the selective removal of waste while retaining essential substances. This distinction is fundamental to understanding how different organisms adapt their excretory systems to their environments.