2024 - JAMB Biology Past Questions and Answers - page 6

The depressed side of Paramecium is the oral groove. The oral groove leads to the gullet, a tube-like structure where food is ingested.

Inbreeding, or mating between closely related individuals, increases the chances of offspring inheriting two copies of a recessive allele, which can lead to the expression of recessive genetic disorders. These disorders are often hereditary diseases.

A gamete is a sex cell (sperm or egg) produced through meiosis. Meiosis results in cells with half the number of chromosomes as the parent cell (somatic cell).

• Somatic cells (body cells) have a diploid (2n) number of chromosomes.
• Gametes have a haploid (n) number of chromosomes.

If a somatic cell has 8 chromosomes (2n = 8), then a gamete will have half that number (n = 4).

An aggregate fruit develops from a single flower that has multiple separate carpels. Each carpel develops into a small fruitlet, and these fruitlets aggregate together to form the aggregate fruit.

The oxygen transported in blood circulation is primarily used for cellular respiration. This process involves the breakdown of glucose (food) in the presence of oxygen to produce energy (ATP), carbon dioxide, and water. Therefore, the main function of oxygen in the body is to facilitate the release of energy from food.

Courtship behavior is a set of actions exhibited by animals to attract a mate. Displays, such as elaborate dances, vocalizations, or the presentation of bright colors, are a common component of courtship behavior.

The pentadactyl limb is a classic example used in comparative anatomy. Comparative anatomy studies similarities and differences in the anatomy of different species. The fact that the pentadactyl limb (five-fingered limb) is found across various vertebrates (e.g., humans, bats, whales) but with different functions (grasping, flying, swimming) is evidence of evolution from a common ancestor. The different functions are due to adaptations to different environments.

A photosynthetic carnivorous plant that feeds on insects is called insectivorous.

Primary succession is the ecological succession that begins in a virtually lifeless area, such as a new volcanic island or a rock left behind by a retreating glacier, where there were no pre-existing communities. The process involves the gradual colonization of the area by pioneer species and the subsequent development of a more complex community over time.

Lamarck's theory of evolution proposes that organisms can pass on traits they acquired during their lifetime to their offspring. This is known as the inheritance of acquired characteristics.