Nowadays we consider lungfishes to be more closely related to tetrapods than the coelacanths are, but in earlier times coelacanths were thought to be the more closely related forms
How have changes in our way of thinking about phylogenetic relationships changed our opinion in this case?
Lungfishes have many of their own derived features (e.g., the pattern of bones on the dermal skull roof) that appeared to debar them from direct ancestry of tetrapods, whereas the coelacanths lacked specialized characters and seemed to have more tetrapod-like features. However, we now no longer look for "ancestors" but for sister-group relationships based on shared derived characters. Lungfishes share derived features with tetrapods that are absent from coelacanths. In contrast, the ways in which coelacanths appear more similar to tetrapods are actually ancestral sarcopterygian features, not indicative of a close relationship.
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If an individual was lacking a key amino acid and so couldn't make and release substance P, what would happen?
A. There would be a surge in activity in neurons that synthesize opiate neurotransmitters. B. There would be increasing sensation of pain generated by the brain, with or without any damage to structures in the periphery. C. They would experience a lack of sensation in some pain pathways. D. There would be an increase in activity in neurons that detect painful stimuli in internal organs. E. Synaptic activity in afferent neurons associated with pain receptors can be inhibited by axon-axon synapses with neurons from descending pathways.
The hydrophilic hormone released from the thyroid gland is ___________
Fill in the blank(s) with correct word
If someone were to mention 'lock and key' in reference to enzymes, you would know that she means that The substrate unlocks the energy potential of the enzyme The enzyme will only work with a specific substrate The enzyme opens the substrate to receive energy to begin the reaction
What will be an ideal response?
Fertilization normally takes place in which female reproductive organ?
a. Uterus b. Ovaries c. Uterine tube d. Vagina