Genetics and Evolution Study Guide

What scientist is responsible for our study of heredity?

Gregor Mendel

What is the difference between dominant and recessive genes?

Dominant- one which keeps other alleles from showing their traits

Recessive- one which is hidden if a dominant allele is present

State Mendel's law of segregation?

Pair of alleles of each parent separate and only one allele passes from each parent on to an offspring

What are alleles? What is a gene?

Allele- different forms of the same gene

Gene- a segment of DNA which controls the production of a particular characteristic

What is the difference between genotypes and phenotypes?

Genotype- the two alleles an organism has at every loci

Phenotypes- actual physical characteristics an organism has due to their genotype

An organism that has two identical alleles for a trait is called ____

homozygous

An organism's ____ refers to the set of alleles it has inherited

genotype

The appearance of an organism as a result of its genotype is its ____

phenotype

What happens during meiosis that would allow genes located on the same chromosome to separate independently of one another?

during meiotic division during metaphase I, during a process called synapsis, crossing over occurs.

Describe an x-linked gene's pattern of inheritance. Give an example of a trait that is inherited this way.

dominant trait or condition caused by a mutation in a gene on the X chromosome.

What is natural selection?

process whereby organisms better adapted to their environment tend to survive and produce more offspring.

What are the 5 main components of Darwin's Theory of Evolution by natural selection?

1 Members of a population have a heritable variations

2 In a population, more individuals are produced each generations that can survive or reproduce

3 Some individuals have adaptive charecteristics that enable them to survive and reproduce better than other individuals

4 An increasing proportions of individuals in succeeding generations have the adaptive characteristics, due to the genetic inheritance of traits

5 the result of natural selection is a population adapted to it

Does evolution occur randomly? If not, what causes it to occur?

No, organisms or their gametes move from one location to another

What are fossils and how do they provide evidence for evolution?

Fossils tell us when organisms lived, as well as provide evidence for the progression and evolution of life on earth over millions of years.

What are the differences between homologous and analogous structures and how do they both show evidence of evolution?

Analogous structures-have different evolutionary ancestries but they have the same function.

Homologous structures-similar in structure but appear in different organisms and have different functions

What are known as vestigial structures and how do they provide evidence of evolution? Give an example of one.

Vestigial structures provide evidence for evolution because they offer clues about the ancestors of organisms, because they are remnants of structures.

What can be inferred about 2 species by comparing their DNA codes, amino acid sequences, or morphology (physical appearance)?

The more the aa sequence or DNA they share the more recently they shared a common ancestor or the more closely related the two organisms are.