test part three - explanations Flashcards
discontinuous vs continuous variations
continuous traits are traits that have a range of types, like heigh weight hair length etc, things that have a range of answers. While oppositely discontinuous variations are phenotypic variations which there is no intermediate types and very few phenotypes. Eye color, skin color, blood type, gender, etc.
how do complex adaptations develop?
Complex adaptations develop over generations of small changes due to the changing environmental needs of the offspring to survive. Such as the human eye which has developed over years to allow us to survive.
Homozygous vs heterozygous
Homozygous alleles are when the two alleles from mom and dad are the same, such as two dominant alleles (AA) or two recessive alleles (aa). While heterozygous alleles are when each inherited allele are different- so Aa. Homozygous alleles produce CAN present a recessive trait if present in both parents, and heterozygous CANNOT present a recessive because it has the dominant gene.
protein synthesis: transcription, translation
In transcription, DNA is read and MRNA (messenger RNA) is created, it brings messages from nucleus to the ribosome. The DNA is “transcribed” into something else to send a message, includes A, U, C,G. While in translation, the mRNA that was created links with tRNA- anticodons and amino acids- to create a peptide chain. So it would connect the opposite to itself. A to U, C to G, Etc. Etc.
Hardy Weinberg equilibrium
The unchanging frequency of genotypes that results from sexual reproduction and occurs in the absence of other evolutionary forces such as natural selection, mutation, or genetic drift.
proportions with two alleles:
freq(aa)=q^2
freq(Aa)=2pq
freq(AA)=p^2
q is frequency of allele a and p is frequency of allele A. (page 58)
DNA replication
chromosomes = coiled up DNA, it replicates during mitosis using the zipper method. It unzips itself and then re-zips with another that fits it to replicate.
maintenance of variation
Mulitple loci can look as if there is blended inheritance, or an equal amount of characteristics from each parent passed down, but in reality its the phenotypes that are blended while the gametes or the genotype that stay distinct. Although a loci presents one way, the DNA from the parents are still passed down therefore the recessive gene is still inherited.
constraints on natural selection
correlated character- meaning that individuals with one wanted trait tend to have another trait that goes with it.
example: birds want deeper beaks to get more available food, but with that comes wider beaks which makes it harder to live in their environment and more likely to die young. this results in a cap of beak depth and width in the population.
“ selection on one trait affects the frequency of a correlated trait”
ancestral vs derived traits
Ancestral traits are traits that are seen farther back in the history of a species, or farther related development and are often seen in the early stages of fetal development. While derived traits are something that are more closely related to a species, such as the ability to walk on two legs, or the adaptation of lactation and the human eye.
evolutionary classification vs cladistics taxonomy
evolutionary classification classifies organisms that use both the patterns of decent and patterns of overall similarity, while in contrast cladistics taxonomy classifies organisms by patterns of decent only.
