Test one Flashcards
fertility
the capacity to produce offspring
fitness
an organisms ability to survive and reproduce in its environment
gene
specific sequence of DNA that contains the instructions for making a particular protein
allele
different versions of a gene ( yellow peas vs green peas)
mutation
a change in the typical DNA frequencies.
Natural selection
the process that produces adaptations. natural selection is based on three categories, the availability of resources is limited, organisms cary in the ability to survive and reproduce, and traits that influence survival and reproduction are transmitted from parents to offspring. When these three categories hold natural selection produces adaptation.
gene flow
migration of genes; any movement of individuals, and/or the genetic material they carry, from one population to another
genetic drift
random change in gene frequencies due to sampling variation that occurs in any finite population. More rapid in small populations than in large populations.
convergence
the evolution of similar adaptations in unrelated species or distantly related populations of the same species. The evolution of camera type eyes in both vertebrates and mollusks is an example of convergence.
blended inheritance
a disproven theory that offspring are a mix of their parents’ characteristics
stabilizing selection
selection pressures that favor average phenotypes. Stabilizing selection reduces the amount of variation in a population but does not alter the mean value of a trait.
chromosome
a linear body in the cell nucleus that carries genes and appears during cell division. Staining cells with dyes reveals that different chromosomes are marked by different banding patterns.
ribosome
an intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell
haploid
of a cell: containing only one copy of each chromosome. Gametes are haploids as are the cells of some asexual organisms. Compare diploid.
diploid
of a cell: containing pars of homologous chromosomes in which one chromosome of each pair is inherited from each parent also refers to organisms whose somatic body cells are diploid all primates are diploid.
gamete
in animals, an egg or sperm
phenotype
the observable characteristics of organisms. Individuals with the same phenotype may have different genotypes.
Genotype
The combination of alleles that characterizes an individual at some set of genetic loci. For example in populations with only the A and S alleles at the hemoglobin locus that locus has only 3 possible genotypes: AA AS and SS (SA is the same as AS).
Homozygous
Of a diploid organism: Having chromosomes that carry two copies of he same allele at a single genetic locus. Organisms that are homozygous are called homozygotes.
Heterozygous
Of a diploid organism: Having cells that carry copies of two different alleles for a particular genetic locus. Organisms that are heterozygous are called heterozygotes.
Mitosis
The process of division of somatic cells (normal body cells) through which new diploid cells are created.
Meiosis
The process of cell division in which haploid gametes (egg and sperm) are created.
“crossing over”
The exchange of genetic material between homologous chromosomes during meiosis crossing over causes recombination of genes carried on the same chromosome.
