hey everybody its mr. speeds and today we'll be covering two different reproductive strategies that species used to pass on their genes K selected species use what I like to call quality over quantity so they have just a few offspring at a time but they take really good care of them and they're able to do this because they live a long time and they can afford to spend their energy in their time on parenting so we have elephants here is a great example on the other hand our selected species take the quantity approach to the question of how to pass on the genes they have many many offspring in the hopes that at least some of them survive and they generally live much shorter lives and often only reproduce once so they can't really afford to produce a few offspring and take care of them they like to really crank out the offspring as I like to say and just hope that some of them survive spiders here are a great example they're gonna have hundreds and hundreds of offspring they're gonna leave them to fend for themselves and again they're just going to hope that some of them happen to survive our objective today is to be able to identify the differences between case lected and our selected species and we have a lot of essential knowledge today the first two are basically everything you need to know about our selected K selected species and we have a new term here - no that's biotic potential which is the maximum reproduction rate of a population this is going to be much higher for our selected than it is for K selected species and then we have to know that not all species are perfectly are selected or perfectly k selected so with most classification systems in science there's a spectrum so we'll talk about how it's not just buying areas such as one or the other and then finally we'll talk about why our selected species are more likely to become invasives and why K selected species are more likely to be negative negatively impacted by invasive species and then the science skill that we'll be practicing at the end of the lesson today is to be describing the patterns or trends in data so as I mentioned in the intro we have the reproductive strategies here R and K selected and they sort of represent the quantity versus quality approach and so before we talk about the characteristics we need to review that these are both reproductive strategies or approaches that different species take to passing on their genes so all species pass on their genes to offspring it's basically the driving force behind all of life and these are just two different approaches to accomplish that goal so they both work and they're both suited to the organisms that use them and again we want to think of them as strategies and focusing on either quality or quantity so K selected species here take the quality approach they're typically larger longer lived animals like large mammals and they only have a few offspring at a time but they take really good care of them so because they live longer they take longer to reach sexual maturity but they also usually have the opportunity to reproduce many times over their lifespan since they only have a few organisms or a few offspring at a time they invest a lot of energy in them they get them food they keep them warm and they might even fight off predators because of this though they have a lower biotic potential or maximum reproductive rate which means they're going to exhibit slower population growth because it takes a long time for them to give birth and raise their offspring their populations just can't grow as fast now this can be a problem if there's an environmental disturbance like a disease or an invasive species because their populations just take so long to recover back to that initial size our selected species on the other hand are going to take the quantity approach so they're generally smaller shorter-lived organisms like insects fish and plants and they often don't live enough to reproduce numerous times so they've really got to make that one-shot count because they don't live long they reach sexual maturity very quickly and they produce many offspring at one time they invest their energy in the production of this large number of offspring but then they invest little to no energy in caring for them so often there's no parental care at all since they don't care for them they need to have a lot of offspring in order to ensure that at least some of them survive so they have a very high biotic potential or maximum reproductive rate however this reproductive rate can also make them more likely to become invasive species because their populations grow so rapidly they often outcome Peet's lower case elected species for reap resources like food or water so here's a quick guide of the basic traits for both case elected in our selected species and again think of K selected species is kind of taking their time slow and steady wins the race they live a long time so it takes them a long time to reach sexual maturity and this also means that they have to protect and care for their offspring for a while as those offspring grow and develop because their populations grow slowly though they're usually relatively stable they exist near their carrying capacity or their maximum population size our selected species are basically the opposite they live short lifespans they reach sexual maturity very quickly and they reproduce many offspring they also invest their energy more in the production of offspring rather than caring for them so it takes a lot of energy for a mother spider or fish to produce thousands and thousands of eggs and then they don't invest that energy and caring for them so this leads to them having very fast population growth but very variable population sizes since they're subject to kind of dramatic increases or decreases so it's important to remember that not every organism is perfectly k-selected or are selected we can see here two extreme examples of a highly K selected organism the chimp or an Haley are selected moister but you'll notice here there's many species that are somewhere in the middle like the Frog and the hare so the frog and the hare going to produce a fair number of offspring compared to the chimp but they're also going to show some parental care compared to the oyster so not every single organism fits perfectly into our selector K selected it is kind of a spectrum so here we have the mother hare who is going to provide quite a bit of care to her offspring they're going to be somewhere in the range of 10 to 12 at a time and frogs even though they may have hundreds of offspring in a reproductive cycle many frogs offer some parental care such as this poison dart frog here that's going to carry tadpoles on her back so again it's a spectrum these organisms aren't going to exhibit the same kind of parental care that pansy mother does having one baby chimp every five years but they're also not going to just leave their numerous offspring to fend for themselves like the oyster so now we're going to talk about invasiveness and disturbance so like I've said earlier both of these reproductive strategies work to pass on their genes or we wouldn't see so many organisms in both groups but they do have some disadvantages so the slow reproductive rate or biotic potential of k-selected species makes them slower to repopulate after environmental change or disturbance such as a forest fire or a disease and then unfortunately there's kind of a double whammy effect on population recovery for the case selected species since they're young are born very vulnerable and usually unable to care for themselves the death of a parent often means the death of their offspring as well so that's more than just a one parent dying that's impacting the population it's also probably killing the offspring their slow sexual maturity and their low biotic potential also makes them more vulnerable to being out competed for limiting resources by highly competitive rapidly reproducing invasive species so as you may guess these invasives are usually our selected species because they repopulate so quickly when they move to a new ecosystem they can oftentimes out-compete the slower reproducing k-selected species they're slow population recovery also leads to K selected species being less likely to adapt to a changing environment this is because they have longer generation times and smaller population sizes so there's less genetic diversity and as a result their populations are less adaptable they're less likely to have beneficial mutations that allow them to quickly evolve and adapt to new environmental conditions so as a result of all these factors K selected species are far more likely to go extinct than our selected species so today our skill that we'll practice is concept explanation and we want to be able to identify one characteristic of an R selected species that could increase the likelihood of the our selected species becoming a more successful invasive species than a K selected species so our second practice skill that we're going to do here is data analysis so we have a data table of zebra mussels and Union in mussels and we want to be able to describe the relationship between zebra mussel and union in Mossel population density in the Hudson River alright everybody thanks for watching today don't forget to like this video if it was helpful and subscribe for future videos and as always think like a mountain write like a scholar