Science Olympiad Test: Heredity and Evolution- 1

• As we move from higher taxonomic rank to lower one, common characters increase.
• Among species, genus, family and families; species is the lowest taxonomic rank. Hence, two individuals of the same species will share maximum number of common characters. 

So, the correct option is '2 individuals of species'.

• Offspring of the cross of first parent individuals are referred to as first filial generation (F₁​). This makes option C correct. Self-fertilization of plants of F_1​ generation obtains F_2​ generation. 
• The dihybrid cross-refers to inheritance of two pairs of contrasting characters by two parents at the same time. For example, a cross of two pea plants, one with yellow and round seeds (YYRR) and other with green and wrinkled seeds (yyrr). 
• A trait that fully manifests itself in the heterozygous condition is referred to as a dominant trait and the population exhibiting dominant trait constitute dominant species. 

According to scientists, aves have evolved from reptiles. The evolution of birds is thought to have begun in the Jurassic Period, with the earliest birds derived from a clade of theropoda dinosaurs named as Paraves. Birds are categorized as a biological class, Aves. The earliest known is Archaeopteryx lithographica, from the Late Jurassic period, though Archaeopteryx is not commonly considered to have been a true bird. Modern phylogenies place birds in the dinosaur clade, Theropoda. According to the current consensus, Aves and a sister group, the order Crocodilia, together are the sole living members of an unranked reptile clade, the Archosauria.

Archaeopteryx is known to be a communicating connection between reptiles and birds because it looks like a bird and has bird wings. The teeth and tail, however, are closer to those of reptiles. Since it implies that birds evolved from reptiles. Therefore Archaeopteryx links reptiles and birds.

Body size is an acquired trait, and cannot be passed on to the progeny.

The snub nose is an inherited trait, and can be passed on to the progeny.

Wings of an insect and forelimbs of a bird are analogous organs, as they have different structures but perform the same function of flying.

Palisade cells of leaves are somatic cells. Each gamete produced by the plant will have half the number of chromosomes present in a palisade cell i.e. 14 chromosomes.

Darwin's theory of evolution comprised of ideas on over-production, struggle for existence and natural selection.

Accumulation of variations over several generations is one of the major factors responsible for speciation. There are several other forces also acting but most important is the accumulation of variations for several generations. This ensures that variations are in accordance with the environmental conditions throughout.