Systemic lupus erythematosus, often abbreviated as SLE or lupus, is a systemic autoimmune disease (or autoimmune connective tissue disease) in which the bodyâs immune system mistakenly attacks healthy tissue.ystemic lupus erythematosus, often abbreviated as SLE or lupus, is a systemic autoimmune disease (or autoimmune connective tissue disease) in which the bodyâs immune system mistakenly attacks healthy tissue.
Natural selection will only cause evolution if there is enough genetic variation in a population. Before the discovery of Mendelian genetics, one common hypothesis was blending inheritance. But with blending inheritance, genetic variance would be rapidly lost, making evolution by natural selection implausible.
There are many theories regarding the emergence of new species â known as speciation â depending on the level of geographic isolation between the two emerging species. Also, speciation can occur due to reproductive isolation. This can be caused by mating differences, sterility or environmental barriers that eventually lead to the adaptive splitting into two species. However, reproductive isolation is not sufficient but internal barriers to gene flow are required for speciation to evolve. Recent studies suggest that natural selection and adaptation may play a more significant role in the early stages of divergence and the evolution of reproductive isolation than previously thought.