* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Natural Selection
Human genetic variation wikipedia , lookup
Gene expression programming wikipedia , lookup
Heritability of IQ wikipedia , lookup
Transgenerational epigenetic inheritance wikipedia , lookup
Quantitative trait locus wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Genome (book) wikipedia , lookup
Point mutation wikipedia , lookup
Dual inheritance theory wikipedia , lookup
Hybrid (biology) wikipedia , lookup
History of genetic engineering wikipedia , lookup
Genetic drift wikipedia , lookup
Polymorphism (biology) wikipedia , lookup
Selective breeding wikipedia , lookup
Koinophilia wikipedia , lookup
Group selection wikipedia , lookup
Population genetics wikipedia , lookup
Natural Selection YOLO! Survival of the Fittest What is the ultimate goal of all living things? To reproduce more offspring and for those offspring to survive means you are the FITTEST! Why? More offspring means survival of YOUR specific traits and hopefully the survival of your entire species! Artificial Selection is when people select the traits that we want passed on to the next generation • People are the choosers Artificial Selection • First animal to be domesticated by humans • About 12,000 years ago hunter-gatherers in Israel placed a body in a grave with its hand cradling a pup. Whether it was a dog or a wolf can’t be known. Scientists know the process was under way by about 14,000 years ago but do not agree on why. • At the molecular level not much changed at all: The DNA makeup of wolves and dogs is almost identical. Scenario 1: "Humans adopted wolf pups and natural selection favored those less aggressive and better at begging for food." • Scenario 2: "Dogs domesticated themselves by adapting to a new niche—human refuse dumps. Scavenging canids that were less likely to flee from people survived in this niche, and succeeding generations became increasingly tame." https://www.haikudeck.com/foxes-anddomestication-education-presentationiWVY2vzVx0# (read on your own) Many things have been artificially selected for human’s benefit, such as… Wild Banana Domesticated Banana Also… Wild Maize Domesticated Corn In natural selection, nature is selective force! In Natural Selection the environment is the chooser Natural selection is a NONRANDOM process by which traits are selected for by nature because they provide some survival benefit. Woolly BEAR! Natural selection explains how evolution can occur. • There are four main principles to the theory of natural selection. Genetic Variation of heritable traits (due to meiosis and mutations)-variety in genes create unique combinations in offspring that allow some traits to be more successful than others in a particular environment. “Variety is the spice of life”— exact clones are prone to failure and extinction! – Overproduction and struggle for survival-organisms don’t control reproduction rate to ensure that some offspring will survive and compete for resources. – Adaptation favorable traits arise over many generations in a population and not in one individual due to selective pressure from environment. – Descent with modification—offspring share characteristics and genetic traits with common ancestor, but there is a change in gene frequency over time. Descent with modification occurs on a species level Source: Berkeley Evolution • Descent with modification — a change in gene frequency over time Beetles of a different color • Most of the beetles in the population (say 90%) have the genes for bright green coloration and a few of them (10%) have a gene that makes them more brown. First Generation • Some number of generations later, things have changed: brown beetles are more common than they used to be and make up 70% of the population. Second Generation • Fitness is the measure of survival ability and ability to produce offspring that survive. Natural selection acts on existing variation. • Natural selection can act only on traits that already exist (the genetic combo that was randomly assigned before fertilization). • Structures take on new functions in addition to their original function. (example: homologous structures). five digits wrist bone Natural Selection Got milk? Lactase mutation • Nomadic-hunter-gatherer ancestors were lactose-intolerant. http://www.hhmi.org/biointeractive/natural -selection-lactose-tolerance • When cattle were domesticated and cow milk became readily available, the mutation for lactase enzyme production (LCT gene) became favorable and became more common in the genotype of future generations. Got Milk? • Remember “linked-genes”? Lactose intolerance mutation is a mutation that is passed on with other certain traits because of its proximity to those genes. • The LCT lactase mutation is found on chromosome 2! Pedigrees show short-term descent with modification Cladograms show descent with modification Dormaalocyon latouri ancestor Cladogram Shows Speciation: Descent from Ancestor(s) http://www.nature.co m/scitable/topicpage/ interpreting-sharedcharacteristics-theplatypus-genome44568# Cladogram • A clade is a group of species that includes an ancestral species and all of its descendants. Clades, like species, are formed by the process of descent with modification. This Cladogram Shows Descent from Ancestor(s) on a MACRO scale (whole tree of animal life)