Echinoderm is the name given to a member of the phylum Echinodermata. They have radial symmetry and this includes sea urchins, sand dollars, sea stars and sea cucumbers. It is suggested that they are related to the chordates which is the answer.
Answer:
The binding of chemical messengers to receptors often results in a shape change, which affects receptor function.
Explanation:
Binding of specific chemical messengers to the corresponding receptors of target cells brings about change in the shape of the receptors. This structural change in the receptor results in the generation of the desired response. It reflects how the form and specific configuration of substances or biomolecules affect their functions.
For example, binding of neurotransmitters to the receptors present on neurons opens the associated ligand-gated ion channels to allow the movement of specific ions through it. In the absence of bound ligand, these channels are present in a closed conformation.
The two richest ecosystems lie in tropical rainforests and coral reefs. On land, tropical rainforests contain many species variation with an abundance of species in bird, mammals, amphibians, and plants. While tropical rainforests occupy only 7 percent of the Earth’s land area, they contain over half of the world’s species. This may be because species richness tends to increase with decreased elevation, increasing solar exposure, and increased precipitation; that is, hot, rainy low-land areas have the most species. In contrast, deserts have low species variation because of low precipitation. On earth, water is majorly important the equation for life. Many of the species are genetically isolated because of habitat size and variation in the build of the land (mountains, equator location, etc) such as seen in the Galapagos islands and the Amazon rainforest, both near and in South America.
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