BS276 Lecture : 32 - k-selected & r-selected species

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wrygaard6

9 Dec 2022

School

University of the Sciences

Department

Biological Sciences

Course

BS276

Professor

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Lesson 18 - K-selected & r-selected

species

Quality vs Quantity

K-Selected - "quality"

● Few offspring, heavy parental care to protect them

● Usually reproduce many times

○ Ex. most mammals, birds

● Long lifespan, long time to sexual maturity = low biotic potential = slow population growth

rate

● More likely to be disrupted by environmental change or invasives

R-selected - "quantity"

● Many offspring, little to no parental care

● May reproduce only once

○ Ex. insects, fish, plants

● Shorter lifespan, quick to sexual maturity = high biotic potential = high population growth

rate

● More likely to be invasive

● Better suited for rapidly changing environment conditions

Trait

K-selected species

R-selected species

Life span

Long

Short

Time to reproductive maturity

Long

Short

Number of reproductive

Few

Many

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Document Summary

Few offspring, heavy parental care to protect them. Long lifespan, long time to sexual maturity = low biotic potential = slow population growth rate. More likely to be disrupted by environmental change or invasives. Many offspring, little to no parental care. Shorter lifespan, quick to sexual maturity = high biotic potential = high population growth rate. Better suited for rapidly changing environment conditions. Low biotic potential (reproduction rate) = hard for population to recover after a disturbance (environmental change) High parental care means death of parent = death of offspring. Invasives (usually r) outcompete for resources with high biotic potential & rapid population growth. Less likely to adapt & more likely to go extinct. High biotic potential (reproduction rate) = more rapid population recovery after disturbance. Low parental care means death of parent doesn"t impact offspring. Not as impacted by invasive species since their population grow quickly.

Related Questions

Factors whose impact on a population increases as population size increases are known as: a. Limiting factors b. Life-history factors c. Distribution factors d. Density-dependent factors 7. Deer mice are a species with individuals who live short lives and grow up rapidly. They have many, small offspring to which they give little parental care. This life-history strategy describes: a. r-selected species b. K-selected species 8. Which type of species is more likely to have its population size remain close to carrying capacity under normal conditions, rather than going through boom and bust cycles? a. density-dependent species b. r-species c. K-species d. prey species 9. In top-down regulation, the size of a rabbit population is determined by: a. The number of foxes and coyotes in the area b. The severity of winter c. The amount of food found in their habitat d. The biotic potential of female rabbits 10. In the Yellowstone ecosystem, what regulates the size of the elk populations? a. Bottom-up regulation factors b. Top-down regulation factors c. In some cases it is bottom-up and in other cases it is top-down regulation. d. Neither one have a significant impact on elk population size.

ultramarinetermite85

Statement 1: k-selected species are less energy efficient because they produce few offspring and grow slowly; Statement 2: r-selected species are more energy efficient because they produce many offspring and grow really fast.

◯ Both statements are true.

◯ Both statements are false.

◯ Only first statement is true.

◯ Only second statement is true.