You might be reading this title and thinking what in the world does “ Evolution shapes life histories.” mean? Well let's take it piece by piece. What is life history? It is the first time an individual reproduced, how many offspring they produce, and how much care the parents give their offspring are all traits that determine the life history of an individual. Life histories analyze the reproduction patterns of species, and how an offspring is raised. For example humans have about 3 kids and give them good care to help them live to maturity and have their own kids. On the other hand, bacterial species reproduce tons of offspring at a time and give little care to them causing the offspring to die easily due to little care. Evolution shaping life history means how are species changing due to the way they reproduce.
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R-selectionSmall nonwoody plants, insects , small rodents, and small lived animals all share similar characteristics. They are known as r-selected species. These species reach sexual maturity at a young age and all produce many offspring at a time. The problem is they can’t care for all their offspring causing many of the offspring to die rapidly due to no parental care. Their ecosystems may consist of many resources for them to live off, but having no parental care causes many to die. They are also very strong when it comes to surviving floods, fires or natural disasters. What may cause them to die off is human activity. For example due to us cutting trees for our needs we may cause species to die off.
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K-selected
r-selected
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K-selectionHumans , large mammals like elephants and bears, and plants like coconut palms are considered k-selected. What does it mean to be K-selected? To be K-selected means:
These species are k-selected because researchers think that the population of that species grows due to the fact that the population is close to reaching carrying capacity. K selected species face the problem of having few resources, so they face the problem of density dependant factors. |