Two other botanists also claimed to have independently rediscovered Mendelian genetics, but Mendel gets credit because he actually laid out the theory fairly completely

• Notice that Mendel, a monk who eventually became head of the monastery, was doing experiments in the context of Darwin's theory of evolution (probably to see if crossbreeding could result in new species)
• even today there are a number of significant scientists who are priests or monks, such as Guy Consolmagno and Luis Archer
  
• He attended the University of Vienna and did get to some scientific conferences
  
• he studied seven traits in pea plants that did not average out
• if you bred a tall plant and a short plant you initially got all tall plants, not plants half way in between in height (because the gene for tallness is dominant)
  
• in the next generation you get one short plant for every three tall plants
• this is the simplest case when one gene controls the trait, many traits are more complicated because they are controlled by more than one gene
• what Mendel discovered most importantly was a mathematical pattern, which wasn't yet that common in biology
  
• it was known that peas tended to not average traits, but it was not clear if this applied to other plants and animals
• traits inherited together (linked traits) were not widespread
• the scientific community had not yet realized the need for Mendel's theory
• Mendel was ignored because he was not much known and publishing in an obscure journal, but also because there wasn't much need for the idea when he first published it--heredity is rarely that simple
  
• the problem remaining once you have Mendelian genetics is what exactly are genes?
  

You need both mutations and Mendelian genetics to be able to show mathematically that evolution works, but they were separate theories and people put them together in different ways.  There were a lot of mixed theories: including or not including natural selection, seeing genes as immaterial or located on chromosomes

Thomas Hunt Morgan proved that genes are on chromosomes (early 1910s)

• studied fruit flies, which had the advantage of a generation every 12 days
  
• he was initially looking for mutations, and when he found one it bred true according to Mendel's ratios
• he found linked traits but the links sometimes broke; this could be explained by recombination that can happen during meiosis, the division of chromosomes for the egg or sperm cell
• they ended up being able to roughly map the layout of genes on the chromosome, without knowing what they were
• he saw mutations as creating new species and didn't focus on natural selection

We still haven't gotten to the Modern Synthesis, of genetics and Darwin's theory of evolution by natural selection of small variations