GENERAL HISTOLOGY

Detailed explanation-1: -An urchin barren is an area of the shallow part of the ocean where the population growth of sea urchins has gone unchecked, causing destructive grazing of kelp forests.

Detailed explanation-2: -Overgrazing. Sea urchins grazing in large numbers (called herds) can eat away at a kelp forest until there’s nothing left, creating an “urchin barren”-a subtidal area where kelp is almost completely absent.

Detailed explanation-3: -Each plate has a single duct where the gametes (eggs or sperm) can be released into the water. 2.-Gonopore. This is the opening at the end of the duct in the genital plate where eggs and sperm are released.

Detailed explanation-4: -Like a porcupine’s quills, sea urchins count on their long spines to deter hungry predators from making them a snack. In fact, the sea urchin gets its name from an Old English word for the spiny hedgehog, a land animal similar to the American porcupine.

Detailed explanation-5: -This combination of extreme warm water events, an absence of urchin predators, and extensive purple urchin recruitment, led to a large-scale shift from kelp forests to an alternate state composed of areas dominated by urchins. This state of the reefs is referred to as “urchin barrens”.