Biology Test 367

Endocrine glands are ductless glands of the endocrine system that secrete their products, hormones directly into the blood. The major glands of the endocrine system include the pineal gland, pituitary gland, pancreas, ovaries, testes, thyroid gland, parathyroid gland, hypothalamus and adrenal glands.

Option A: "Intrinsic rate of natural increase" – Incorrect, this is represented by r in the equation.

Option B: "Biotic potential" – Incorrect, biotic potential generally refers to the maximum reproductive capacity of an organism under optimal conditions, often considered similar to r but not specifically the same as K.

Option C: "Carrying capacity" – Correct, as K in the equation is specifically describing the carrying capacity, which is the maximum population size that the environment can sustain indefinitely given the food, habitat, water, and other necessities available in the environment. Option D: "Population density" – Incorrect, while N relates directly to population density at any time, K is about the upper limit of that density sustainable by the environment. Therefore, Option C is the correct answer. The variable K in the Verhulst-Pearl logistic growth equation indeed stands for the carrying capacity.

"Ex situ" conservation involves conserving species outside their natural habitats, such as storing seeds in seed banks, keeping species in zoological parks, or maintaining them in botanical gardens.

Since resources of growth for most animal populations are finite and become limiting sooner or later, the logistic growth model is considered as more realistic.

Given pyramid is pyramid of numbers in a parasitic food chain. In a parasitic food chain, the pyramid of numbers is inverted. This is due to the fact that a single plant may support the growth of many herbivores and each herbivore in turn may provide nutrition to several parasites, which in turn support many hyper-parasites. Thus, from the producer towards consumers, the number of organisms gradually increase, making the pyramid inverted in shape.

Pyramids of biomass are comparatively more fundamental, as they, instead of geometric factor, show the quantitative relationships of the standing crops. In grassland and forest, there is generally a gradual decrease in biomass of organisms at successive levels from the producers to the top carnivores. Thus, pyramids of biomass and number are upright in terrestrial ecosystems.

Phosphorus has a sedimentary cycle of matter Its reservoir pool is phosphate rocks while cycling pool is terrestrial and aquatic ecosystems. Atmosphere or gaseous phase is absent.

Biogenetic law or Recapitulation theory was given by Ernst Haeckel in 1866. It states that 'ontogeny repeats phylogeny'. Ontogeny is the life history of an organism while phylogeny is the evolutionary history of the race of that organism. This means that an organism repeats its ancestral history during its development.

Bipolar neurons have one axon and one dendrite. These neurons are found in specialized areas like the retina of the eye, where they transmit visual signals from photoreceptor cells to other parts of the visual system.

Steroid hormones, being hydrophobic molecules, diffuse freely into all cells and act within the cell. Steroid hormones enter the cytoplasm of a target cell and bind with specific receptor proteins (mobile). Hormone-receptor complex then diffuses into nucleus and activates specific genes to form a new protein. This protein carries out the specific response for a particular steroid hormone.