BIOLOGY CH 8 Flashcards
What are the results after centrigue?
Pellet at the very bottom and supernatant
Do all genes produce proteins as end products?
No. Some genes produce tRNA, rRNA, as well as other small nuclear RNA genes; these do not produce proteins
What is classical dominance?
When one allele is dominant and another is recessive meaning that although there are 3 different genotypes, there are only 2 different phenotypes.
In males, meiosis occurs in the ______ with haploid ______ as the end result; in females meiosis in the ______ produces _______ .
Testes; Spermatozoa; Ovaries; Ova
Incomplete dominance
Pink flowers
Codominance
Red and white flowers; blood type
Pleitropism
One gene influences multiple phenotypes
Polygenism
One phenotype is affected by many genes
Epistasis
One gene expression is dependent on another gene’s
Recessive lethal alleles
Mutant alleles can cause death of an organism when present in homozygous manner
The failure of genes to display independent assortment is called ________ .
Linkage
How do you calculate frequency of recombination?
Number of recombinants / Total number of offspring
Gene pool
The sum total of all genetic information in a population
Fitness
How successful an animal is in passing on its alleles to future generations. The way to have greater fitness is by having more offspring that pass on their alleles to future generations of the population
Directional selection
When natural selection removes one extreme of a phenotype and over time the average moves closer to the other extreme
Divergent selection
When natural selection removes the average of a phenotype causing the extremes to be more prevalent
Stabilizing selection
When natural selection removes both extremes of a phenotype and over time the average phenotype becomes more prevalent
Kin selection
Animals sacrificing themselves for the sake of the alleles they share with another individual
Hybrid inviability
Hybrid offspring do not develop or mature normally, and normally die in the embryonic stage
Hybrid sterility
A hybrid individual is born and develops normally, but does not produce normal gametes, and thus is incapable of breeding
Hybrid breakdown
When two hybrids mate successfully to produce a hybrid offspring, but this second generation hybrid is somehow biologically defective
Homologous structures
Physical features shared by two different species as a result of a common ancestor
Analogous structures
Serve the same function in two different species, but not due to common ancestry
Convergent evolution
Two different species evolve to look-alike (many analogous structures) due to similar selective pressures
