The document discusses r and K selection strategies. r strategists prioritize rapid growth and reproduction over survival and have characteristics like small size, short lifespans, early maturity, and generalism. K strategists emphasize long-term survival over rapid reproduction and tend to be large, live long lives, mature late, invest heavily in parental care, and specialize in narrow niches. Most species exhibit a mix of r and K traits along a continuum.

1. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
Two general types of life strategies can be identified for most organisms
•
r = growth rate
Equilibrium or K strategy species (a species -not the individual - is at carrying capacity K)
Opportunist or r strategy species (a species exists in the exponential phase of of
population growth r)

2. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
What are K and r
• The two variables that
define a population curve
• r = growth rate
• K = carrying capacity

3. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
Population
What are K and r 120
• The two variables that 100
define a population curve 80
• r = growth rate 60
• K = carrying capacity
Growth
40
20
Intrinsic rate of growth r
0
0 50 100 150 200 250 300
Time

4. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
K Population
What are K and r 120
• The two variables that 100
define a population curve 80
• r = growth rate 60
• K = carrying capacity
Growth
40
20
0
0 100 200 300 400 500 600
Time

5. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies

6. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
K strategists

7. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
K strategists
• Low reproductive rate

8. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
K strategists
• Low reproductive rate
• Large investment in parental care

9. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
K strategists
• Low reproductive rate
• Large investment in parental care
• Late maturity

10. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
K strategists
• Low reproductive rate
• Large investment in parental care
• Late maturity
• Slow growth

11. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
K strategists
• Low reproductive rate
• Large investment in parental care
• Late maturity
• Slow growth
• Large organisms

12. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
K strategists
• Low reproductive rate
• Large investment in parental care
• Late maturity
• Slow growth
• Large organisms
• Late successional species

13. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
K strategists • Niche specialist
• Low reproductive rate
• Large investment in parental care
• Late maturity
• Slow growth
• Large organisms
• Late successional species

14. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
K strategists • Niche specialist
• Low reproductive rate • Require stable environment
• Large investment in parental care
• Late maturity
• Slow growth
• Large organisms
• Late successional species

15. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies

16. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
r strategists

17. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
r strategists
• High reproductive rate

18. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
r strategists
• High reproductive rate
• Low investment in parental care

19. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
r strategists
• High reproductive rate
• Low investment in parental care
• Early maturity

20. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
r strategists
• High reproductive rate
• Low investment in parental care
• Early maturity
• Rapid growth

21. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
r strategists
• High reproductive rate
• Low investment in parental care
• Early maturity
• Rapid growth
• Small organisms

22. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
r strategists
• High reproductive rate
• Low investment in parental care
• Early maturity
• Rapid growth
• Small organisms
• Pioneer species species

23. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
r strategists • Generalists
• High reproductive rate
• Low investment in parental care
• Early maturity
• Rapid growth
• Small organisms
• Pioneer species species

24. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
r strategists • Generalists
• High reproductive rate • Rapidly adapt to environmental
variation
• Low investment in parental care
• Early maturity
• Rapid growth
• Small organisms
• Pioneer species species

25. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
The reality is more of a continuum

26. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
The reality is more of a continuum
Zebra
Rabbit
Bacteria
r K

27. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
If life Tables (Survivorship) is plotted for
different species three generalised types of life
curve form
Type 1 - Survivorship is high, most mortality
later in life span (K strategy)
Type II - Constant mortality throughout life
span (in between)
Type III - High mortality early in life, low
survivorship into late life span (r Strategy)

28. Topic 2: Ecosystems
2.6 Changes
2.6.3 - 2.63: r and K strategies
If life Tables (Survivorship) is plotted for
different species three generalised types of life
curve form
Type 1 - Survivorship is high, most mortality
later in life span (K strategy)
Type II - Constant mortality throughout life
span (in between)
Type III - High mortality early in life, low
survivorship into late life span (r Strategy)