The diagram below shows the early embryos of a fish, reptile, and bird. What evidence do you see could be used to determine relatedness? What is the name given to the study of the similarities and differences in embryos of different organisms? What evidence in adult fish, reptiles, and birds would show relatedness?

an individual’s sex (i.e., whether they are a male or female) is determined by the sex chromosomes. most people have two sex chromosomes, one that is inherited from their mother and one that is inherited from their father. typically, females have two x chromosomes (xx) and males have one x chromosome and one y chromosome (xy). conditions caused by changes (“mutations”) in genes located on the x chromosome are considered x-linked.

x-linked recessive inheritance

most x-linked conditions are recessive. this means that in a person with two x chromosomes (most females), both copies of a gene (i.e., one on each x chromosome) must have a change or mutation whereas in a person with one x chromosome (most males), only one copy of a gene must have a mutation. a female with a mutation in one copy of a gene on the x chromosome is said to be a “carrier” for an x-linked condition. a male with a mutation in a gene on the x chromosome is typically affected with the condition. because females have two copies of the x chromosome and males have only one x chromosome, x-linked recessive diseases are more common among males than females. however, x-linked recessive diseases can occur in both males and females.

for x-linked recessive disorders, an unaffected carrier mother who has a mutation in a gene on the x chromosome can transmit either the x chromosome with this mutation or a “normal” x chromosome to her children. if the father is unaffected, none of her daughters will be affected and all of her daughters will be unaffected—since they will inherit at least one normal x chromosome from their father. however, each daughter will have a 50% chance of being an unaffected carrier like her mother and a 50% chance of both x chromosomes being normal.

linnaeus is the father of taxonomy

explanation:

which is the system of classifying and naming organisms. one of his contributions was the development of a hierarchical system of classification of nature. today, this system includes eight taxa: domain, kingdom, phylum, class, order, family, genus, and species.

reflection is the bouncing back of a propagating wave when it encounters a barrier; usually shows an image of the source of light wave

1) bounces back from an opaque material

2) bounces back from the boundary

3) seen in mirrors

refraction is the bending of a propagating wave having a shift of direction as it passes through different media; usually seen in lenses to magnify or lessen

1) passes through a prism

2) moves from one medium to another

3) seen in lenses