Chapter 2 Flashcards
Species Heredity
The genetic endowment that members of a particular species have in common; a contributor to universal species traits and patterns of maturation.
Natural Selection
individuals who have characteristics advantageous for survival in a particular environment are most likely to survive and reproduce. Over many generations, this process of “survival of the fittest” will lead to changes in a species and the development of new species.
Ethology
A discipline and theoretical perspective that focuses on the evolved behavior of different species in their natural environments.
Slow Life History Strategy
An evolved approach in safe and predictable environments in which parents are supportive of children, sex and child bearing are postponed during adolescence until resources are in place to raise a family, couples form long-term relationships, parents invest energy in raising a small family, and children have a good chance of surviving.
Fast Life History Strategy
An evolved approach in harsh and unpredictable environments in which parents are not very supportive of children, sex and child bearing begin early, romantic partnerships often do not last, and children focus on surviving in the present rather than on preparing for the future.
Cultural Evolution
Change in a species achieved not through biological evolution but through learning and passing on from one generation to the next new ways of adapting to the environment.
Conception
The moment of fertilization, when a sperm penetrates an ovum, forming a zygote.
Zygote
A single cell formed at conception from the union of a sperm and an ovum.
Chromosome
A threadlike structure made up of genes; in humans, there are 46 chromosomes in the nucleus of each cell.
Meiosis
The process in which a germ cell divides, producing sperm or ova, each containing half of the parent cell’s original complement of chromosomes; in humans, the products of meiosis normally contain 23 chromosomes.
Mitosis
The process in which a cell duplicates its chromosomes and then divides into two genetically identical daughter cells.
DNA
Deoxyribonucleic acid, the double helix molecule whose chemical code makes up chromosomes and serves as our genetic endowment; it is made up of sequences of the chemicals A (adenine), C (cytosine), G (guanine), and T (thymine)
Crossing Over
A process in which genetic material is exchanged between pairs of chromosomes during meiosis.
Identical Twins
Monozygotic twins who develop from a single zygote that later divides to form two genetically identical individuals.
Fraternal Twins
Twins who are not identical and who result when a mother releases two ova at roughly the same time and each is fertilized by a different sperm.
X Chromosome
The longer of the two sex chromosomes; normal females have two X chromosomes, whereas normal males have only one.
Y Chromosome
The shorter of the two sex chromosomes; normal males have one Y chromosome, whereas females have none.
Genotype
The genetic endowment that an individual inherits.
Phenotype
The way in which a person’s genotype is expressed in observable or measurable characteristics.
Gene Expression
The activation of particular genes in particular cells of the body at particular times in life.
Single gene pair inheritance
The genetic mechanism through which a characteristic is influenced by only one pair of genes, one gene from the mother and its partner from the father.
Domiant Gene
A relatively powerful gene that is expressed phenotypically and masks the effect of a less-powerful recessive gene.
Recessive Gene
A less powerful gene that is not expressed phenotypically when paired with a dominant gene.
Sex Linked Inheritance
Mechanism of inheritance in which a characteristic is influenced by single genes located on the sex chromosomes (usually the X chromosome).
Hemophilia
A deficiency in the blood’s ability to clot. It is more common among males than females because it is associated with a sexlinked gene on the X chromosome.