Biology Test - 1

The genes with multiple phenotypic effects are pleiotropic genes.

Pleiotropy occurs when one gene influences two or more seemingly unrelated phenotypic traits. Such a gene that exhibits multiple phenotypic expressions is called a pleiotropic gene.

In gymnosperms, inside the nucellus, one cell differentiated into megaspore mother cell. It undergoes reduction division (meiosis) to form a linear tetrad of four haploid megaspores. Usually, the upper 3 megaspores towards micropyle degenerate while the lowermost functional megaspore (embryo sac cell) undergoes free nuclear division followed by wall formation to form a cellular female gametophyte or endosperm. Hence, the endosperm in gymnosperms is haploid as it is formed before fertilisation, from a single megaspore.

Hence, The correct answer is A.

The term species is the lowest taxonomic category or the least inclusive taxon. The term was coined by John Ray in his 1686 work titled "History of plants”.

Hence, The correct answer is C.

The scientific names of the organisms are the binomial nomenclature with genus and species names written in italics. The genus name starts with a capital and later all the letters are in small. The other names of the ranks in the hierarchical classification start with capitals but are not written in italics, or underlined or printed differently.

Thus, the correct answer is option A.

Sequoia sempervirens is a gymnosperm. It is the sole living species of genus Sequoia. Its common names include coast redwood, California redwood. It is an evergreen, long-living monoecious tree.

Hence option B is the correct answer.

A tautonym is a binomial name in which the genus and the species are given the same name. For example, there exists a species of gorilla whose scientific name is Gorilla gorilla. Iguana iguana is another example of a tautonym.

Hence, The correct answer is B.

The International Code of Zoological Nomenclature (ICZN) is the set of rules and recommendations used in animal classification. The expansions of the remaining options are as follows:

ICBN - International Code of Botanical Nomenclature

ICVN - International Code of Viral Nomenclature

ICNCP - International Code of Nomenclature for Cultivated Plants

Hence, The correct answer is A.

In lower plants, the gametophyte phase is dominant. The plant body is haploid and the gametes are formed by mitotic division. Fusion of gametes forms the diploid sporophytic zygote which then undergoes meiosis to form the gametophytes.

Hence option A is the correct answer.

Amphibia, Reptilia, Aves and Mammalia are all classes under superclass Tetrapoda, which further, is classified under subphylum Vertebrata. Birds are grouped under the class Aves. Examples for Amphibia, Reptilia and Mammalia are frog, snake, and bear respectively. Felis is a genus of cats.

Hence, The correct answer is A.

Pisum and maize do not require water for fertilization. Pisum is a bisexual plant which is having male and female flowers on the same plant. Thus, self-pollination takes place and in Maize, cross-pollination takes. In this, pollens are transferred from anther to stigma with the help of wind. So, it does not require water in fertilization.

Dryopteris and Selaginella come under the category of bryophytes. Bryophytes are the small and non-vascular plants that play an important role in regulating the ecosystem. Water is required for the fertilization in the bryophytes that is Dryopteris and Selaginella. This is because the gametes of bryophytes release in water and that is why fusion occurs inside the water and thus, forming a diploid zygote which then develops into a sporophyte.

Vallisneria comes under the category of hydrophytes. As the name suggested that this category is related to water. So, hydrophytes are plants that grow in water. Vallisneria in which a male flower that detaches on maturity and is ready to float on the surface of the water. While female flowers grow under the water and with the help of long stalks they come on the surface of the water. As soon as stalks grow flowers become vertical to horizontal and due to this cup-like depression formed and then, male flowers which are floating on the surface fall in the cup-like depression. Thus, pollination takes place.

The vascular cambium normally gives rise to secondary xylem.

Vascular cambium is a layer of meristematic tissue which is present between the primary xylem and primary phloem. It divides to form secondary xylem and phloem and helps in secondary growth and wood formation.

Annelida, Arthropoda and Echinodermata are invertebrate phyla in the Kingdom Animalia. Tetrapoda is a superclass of jawed vertebrates (which come under phylum Chordata).

Hence, The correct answer is C.

Taxa are arranged in a hierarchical manner from a small group of very closely related organisms to a broader group with more dissimilarities. As we go in the ascending order the number of common characteristics decreases and the grade increases and vice-versa, that is in the descending order, the number of common characteristics increases and the grade decreases. For example, any genus (lower grade of classification) has members with more similarities as compared to a family (a higher grade of classification) which has members with fewer similarities among them.

Hence, The correct answer is C.

A group of genera having similar characters comprise a family. In biological classification, family is one of the eight major/obligate taxonomic ranks; it is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks above the rank of genus. In vernacular usage, a family may be named after one of its common members. e.g., Blattidae - The family of common household cockroaches (Blatta is a commonly seen genus of cockroach).

Hence, The correct answer is D.

A scientific name contains information about its genus and species.

The scientific name of an organism is used to identify it anywhere in the world. Under binomial system of nomenclature, each organism has scientific name consisting of two parts. First part is genus and second part is the species. For example- the scientific name of mango is Mangifera indica, scientific name of house fly is Musca domestica.

Hence, The correct answer is B.