Unit 3 Lesson 2 : K-Selected r-Selected Species

Essential Knowledge

-We have made a connection between degree of disturbance/stability of ecosystems and type of species that thrive there. -many species are not uniquely r-selected or K-selected -K-selected species are more effected by invasive species

Mosquito

Adult mosquitoes mate within the first few days after emerging After mating live 3-5 days Females lay up to 100 eggs at a time; eggs are hardy and can overwinter R selected species

Explain : why most invasive species are r- selected species

Have high reproductive potential and grow and mature quickly Able to colonize areas easily and may outcompete native specialist species

Random Information

Reproductive strategy of a species is a product of adaptation and natural selection Some species have both r-selected and K-selected species Biotic Potential- maximum reproductive rate of a population in ideal conditions R selected species tend to be generalists K selected species tend to be specialists

Reptiles

Sea turtles have traits both r-selected and K-selected species Have long lifespan (K) Produce a large number of eggs that they abandon (R)

K-selected species

Tend to be large Have few offspring/reproduction event Expend significant energy for each offspring Mature after many years of parental care; have long life spans Reproduce more than once in their lifetime Live in stable conditions Competition for resources in K-selected species' habitats is usually relatively high.

Explain : why K- selected species are typically more adversely affected by invasive species than r- selected species.

They are typically specialists that have a low population growth rate Invasive species are generalists that can quickly reproduce and take over a habitat R selected species are minimally affected by invasive species , they can easily switch to a different resource to avoid competition

Example)

Most likely an invasive species : Cane Toad Most likely a K- selected species : Elephant

Eagle

Continuum

Osprey

Continuum

Classifying species

Many organisms cannot be categorized as strictly r-selected or K-selected; continuum <- Insect, Fish, Frog, Rabbit, Human ->

Giant Panda

May give birth to two offspring but usually only one cub survives Cubs stay with mothers for up to three years and will not reach sexual maturity until 4-8 years old Female may only produce 5-8 cubs in her lifetime Lifespan: 14-20 years K selected species

R-selected Species

tend to be small Have many offspring Expend or invest minimal energy for each offspring Mature early; have short life spans May reproduce only once in their lifetime Are able to thrive in disturbbed environments Competition for resources in R-selected species' habitats is typically relatively low.