QCE Biology Revision 4

Allopatric speciation can be defined as:

• reproduction from an ovum without fertilisation.

• a situation where two subpopulations of a species are reproductively isolated from one another due to habitat differences within the same geographical region.

• closely related but reproductively isolated species living in the same geographical region.

• species that result when two populations of the same species become isolated from each other due to geographical changes.

In the nitrogen cycle, the bacteria that convert ammonia into nitrate can be correctly identified as:

• denitrifying bacteria.

• nitrifying bacteria.

• nitrogen-fixing microorganisms.

• lightning.

The figure shows a phylogenetic tree of primates. Identify which of the following is more closely related to Homo sapiens.

• P. pygmaeus

• P. paniscus

• G. gorilla

• Australopithecus

Orangutans are native to Indonesia and Malaysia. Found in the forests of Borneo is Pongo pygmaeus and, in Sumatra, Pongo abelii. A third species – Pongo tapanuliensis – is also found in Sumatra, where it was identified in 2017. Deduce which of the following all three orangutans belong to.

• Same genus, different species

• Same species, different genus

• Same class, different genus

• Same genus and species

A tolerance range can be correctly defined as:

• the level of an abiotic factor that an organism will survive best.

• the inability of an organism to function at maximum efficiency.

• the range of biotic factors within an ecosystem.

• the range of a particular abiotic factor in which an organism can survive.

The complementary base pairing of nitrogenous bases within DNA can be identified as:

• guanine and thymine; cytosine and adenine.

• guanine and cytosine; adenine and thymine.

• guanine and adenine; cytosine and thymine.

• guanine and cytosine; adenine and uracil.

Identify which one of the following species is more closely related to Eucalyptus alba.

• Ardea cineria

• Ardea alba

• Eucalyptus regnans

• Quercus alba

An analogous structure is described as:

• a structure that has different functions but a similar structure and development.

• a structure that is smaller and simpler than those in related species and has lost its original function.

• a structure with a similar function but no structural relationship.

• the growth and development of a zygote until birth.

A population of 3000 rescued orangutans was recorded in the rehabilitation forest in Borneo in 2018. During the year, 1000 of these orangutans died, 50 orangutans were born, 100 orangutans moved to a nearby forest and an additional 75 orangutans were added to the forest as they were rescued throughout the year. Infer the type of change that is likely to be seen in this population.

r = (b+i)-(d+e)

• The population will increase and will continue to grow in numbers exponentially.

• The population will neither increase or decrease but will remain constant.

• The population will decrease and is unlikely to survive.

• The population has reached carrying capacity.

The main purpose of gene expression is to

• transcribe a gene

• produce hormones

• maintain homeostasis

• synthesise a functional gene product