Genetics And Evolution

Homo erectus fossils were discovered by Eugène Dubois in 1891 on the island of Java, Indonesia. These fossils had a cranial capacity of approximately 900 cc, which is greater than earlier hominids like Homo habilis but less than that of modern humans.
- Homo habilis had a cranial capacity around 600–800 cc and lived earlier.
- Homo neanderthalensis appeared later and had a larger brain size (~1400 cc).
- Ramapithecus is a much older ape-like ancestor with even smaller cranial capacity and is not part of the Homo genus.
Hence, the fossil found in Java in 1891 with a 900 cc cranial capacity belongs to Homo erectus.

Genetic drift is a mechanism of evolution that causes random changes in allele frequencies in a population. It has a stronger effect in small populations and often leads to the loss of rare alleles, thereby reducing genetic variation over time.
- Adaptive radiation involves diversification from a common ancestor to occupy different niches and increases diversity.
- Gene flow introduces new alleles into a population, increasing genetic variation.
- Reproductive isolation leads to speciation but does not directly eliminate low-frequency alleles.
Hence, Genetic Drift is the correct answer as it eliminates low-frequency alleles and reduces variation.

Dryopithecus is considered an early ape-like hominoid showing more resemblance to apes.
Ramapithecus and Australopithecus show intermediate traits between apes and humans.
Homo ergaster is an early human species, less ape-like.

Therefore, the hominoid most ape-like is Dryopithecus.