who proposed that natural selection is the cause of mimicry among South American butterflies?
Henry Walter Bates
populational selection that changes the average value of a trait when one extreme is selected against
ex. slower animals ge preyed/weeded out and future generations are breeded faster because slow ones don't reproduce
populations slection that acts on traits in which both extremes are selected against
ex. traits used in mate identification ex. mammalian gestation period (mortality of mom ^ as gestation period is on either extreme because birth is so complicated---modern medicine has warped this gap phenomenon though)
populational selection i whichthe most common of the population is selected against
Who did Darwin marry?
exhibited a list of "trade offs" between marrying/not marrying her
systematic difference in form (morphology) between the males and females of a particular species
Darwin proposed that this evolved through sexual selection
This process operates on characters that help organisms obtain mates, but are of little value, or possibly disadvantaeous, in day-to-day survival
what are the 2 processes involved in sexual selection?
a place where males gather at tradtional display ground
strategies employed by each sex to ensure reproductive success
females: choosy, discriminating males:aggressive, competititve, flashy, less discriminating
Do males or females have greater reproductive potential?
males-dont' have to carry the offspring, so can produce more
Who was rthe record man who fathered the most children?
Mlai Ismail (1646-1727)
342 daughters 525 sons
Who was the record woman who mothered the most children?
a russian peasant in the 18th century
69 children (through multiple births)
what factors serve to distinguish between species?
1. physical differences 2. variation within species 3. sexual differences 4. age-related differences 5. seasonal differences
What three underlying principles define the biological species concept?
1. groups of populations that can exchange genes 2. produce fertile offspring 3. are reproductively isolated from other such groups
What are the types of pre-mating reproductive isolating mechanisms?
1. mechanical isolation 2. temporal isolation 3. ecological isolation (1 type thrives in dry, other in wet)
What type of post-mating barrier is in place if mating does occur?
gametic isolation-- gametes don't merge
if you only find a particular species of birds on an isolated island, then these birds are said to be what____to the island?
the transfer of alleles or genes from one population to another
If a population of a species radiates out ot a distinct island, adaptto the new infironment and significantly reduce the amount of gene flow for many generations, their ability to reproduce with each other may cease...what is this an example of?
due to adaptive radiation
what type of speciation occurs when there is no geographic isolation?
What type of speciation is occurring if tw populations coexist next to eachother for thousands of years and them speciate
spontaneous polyploidy in a single individual
induced polyploidy via hybridization and meiotic disfunction
the effect of gamete number going wrong and producing more than 2 paired homologous chromosomes