Lecture Twenty Three - Evolution I

Question 1

How do the number of genes differ between land and aquatic plants?

Answer 1

Land plants seem to need more genes. Perhaps because plants began in the water and require extra features in order to survive on the land.

Question 2

What is the homeobox gene?

Answer 2

Also known as the hox gene. This regulates the development of organisms. Control the body plan of an embryo. The order in which genes appear on the chromosome correspond tot he order in which they appear on the body of the organism.

Question 3

What is the SRY gene and the SOX3 gene?

Answer 3

SRY - It is the gene only on the y chromosome that leads to the development of a male. SOX3 - A transcription factor which is homologous to the SRY gene, but on the X chromosome.

Question 4

How do transitions in the fossil record demonstrate decent with modification (with regards to the evolution of the jaw)?

Answer 4

The quadrate and articular bones become the inner ear bones.

Question 5

What is natural selection?

Answer 5

Does not increase genetic diversity within a species (however useful in such diversity might be for the survival of the species). Can favour the spread of genes that shorten the average lifespan of individuals with those genes - not always positive. Can favour siblicide within a nest of offspring and parental indifference to the killing. Does not promote ‘harmony’ in nature, no trait is favoured by selection solely for the benefit it confers on another species.