exam 1 Flashcards
What traits evolve … (according to darwin)
- must be inherited (lamark was wrong)
- must show variation between individuals (inbreeding reduces variation
- environment must exert some pressure on the traits (some variants must provide an advantage or disadvantage)
three types of finches
cactus eater, seed eater, and insect eater (each had varied beak size
Darwin’s evidence came from
homology, embryology, vestigial structures, biogeography, paleontology, comparative anatomy, and selective breeding
structural genes
code for structurally important molecules (hox genes, sonic hedgehog)
regulatory genes
code for structurally important molecules (proteins, fibers, etc.)
epigenetic and inductions
tissue-tissue interactions that have demonstrable effect on morphologies (ex: teeth)
genes encode for instructions of how to make RNA , RNA is read to produce what?
proteins, hormones, etc… the raw materials for tissue , organ, etc production
homeotic gene influence (hox genes) do what?
mediate epigenetic interactions
- also known as pattern formation genes
- segmentation genes for example
- serial homology (similar structure bc common ancestor)
- forelimbs/hindlimbs
___ genes are found in all segmented animals
homeotic
homeobox genes are found in…
arthropods (+annelids), vertebrates (many vertebrate HOX genes are found with drosophila primers)
Genotype
make phenotypes! are defined as simple traits, single genes, or whole chromosomes (sex determination)
two allele- one from the mother and one from the father
phenotype
outward manifestation of the genotype –> physical traits, enzymes, etc… xx female genotype = female phenotype, xy male genotype = male phenotype, 50 percent probability either gender
what are the three types of alleles in the ABO blood system?
recessive, dominant, and co dominant
individuals have two alleles
dominant allele
The allele posssed in a heterozygote
co dominant allele
when both alleles are expressed in a heterozygote
recessive
the allele that is not expressed in a heterozygote
obesity is a …
complex interaction between genes, environment, and phenotype, there are 32 genes associated with obesity
gregor mendel
plant experiments… established the idea of particulate inheritance (no blending) but NOT ALL TRAITS ARE MENDELIAN… discovered dichotomous variation..
mendel’s postulates about inheritance (1)
- hereditary characteristics are controlled by particulate unit factors that exist in pairs in individual organisms
- traits remain discrete (not diluted over time)
- because now we know their genes and the exact sequence of genes is preserved through generations
Mendel’s 2nd postulate
when an individual has two different unit factors responsible for a characteristic, dominant (expressed) recessive (not expressed) —> recall some phenotype traits are influenced by multiple genes
Law of segregation
no bias between maternal and paternal source
law of independent assortment
features are passes onto offspring individual of eachother
linkage
genes found on same chromosome closer = more linkage
crossing over
makes possible the independent assortment of linked genes