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.
T he primary mechanism of change over time is natural selection, elaborated below. This mechanism causes changes in the properties (traits) of organisms within lineages from generation to generation. The Process of Natural Selection. Darwinâs process of natural selection has four components. 1  Variation. 2  Organisms (within populations) exhibit individual variation in appearance and behavior.