Bio351 tarahillextracredit
Upcoming SlideShare
Loading in...5
×
 

Like this? Share it with your network

Share

Bio351 tarahillextracredit

on

  • 178 views

 

Statistics

Views

Total Views
178
Views on SlideShare
178
Embed Views
0

Actions

Likes
0
Downloads
0
Comments
0

0 Embeds 0

No embeds

Accessibility

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Bio351 tarahillextracredit Presentation Transcript

  • 1. Ecology of a PopulationBy:Tara Hill
  • 2. Population DefinedA population is:A group of organisms of the same speciesoccupying a particular space at a particulartime
  • 3. Population Characteristics:Distribution:where organisms are found onearth, determined by biotic/abiotic factorsDispersion: spatial distribution of individuals ofa population -- three general kinds ofpatterns:
  • 4. clumped (aggregated) dispersion -- individualsclumped together -- resources in a habitatmay be patchy in distribution which causesorganisms to form "clumps"
  • 5. Uniform-individuals are about equal distancefrom one another-caused by competition among individuals in thesame population
  • 6. Random-habitat is relatively uniform soindividuals are neither repelled or attracted toone another.
  • 7. Population SizeA balance between:• Natality=birth rate (b)• Mortality=death rate (d)(b)>(d)=population size increases(b)<(d)=population size decrease(b)=(d)=population size is constant
  • 8. Factors affecting population size besidesnatality/mortality• Immigration rate (i) (increases pop. size)• Emigration rate (e) (decreases pop. size)Growth rate equation:r=(b-d) + (i-e)
  • 9. Population GrowthBiotic Potential=-promotes positive growth-intrinsic factors(litter size, gestation)Environmental Resistance=-limits growth-extrinsic factor(weather, food supply)
  • 10. Patterns of growthExponential growth (J shaped curve)• biotic potential(rm)=maximum value
  • 11. Logistic growth (S shaped)K=carrying capacity=population size that isbased on number of resources available
  • 12. Limiting factors:Density dependent:-competition-disease-predation-foodDensity independent:-weather-catastrophes
  • 13. Natural Selection:• limiting factors placestresses on a population• the best adapted organismswill survive and get toreproduce and pass on theirgenes with the adaptationto their offspring• over long periods of timethis can lead to a change inspecies
  • 14. Population GrowthBiotic Potential=-promotes positive growth-intrinsic factors(litter size, gestation)Environmental Resistance=-limits growth-extrinsic factor(weather, food supply)
  • 15. Patterns of growthExponential growth (J shaped curve)• biotic potential(rm)=maximum value
  • 16. Logistic growth (S shaped)K=carrying capacity=population size that isbased on number of resources available
  • 17. Limiting factors:Density dependent:-competition-disease-predation-foodDensity independent:-weather-catastrophes
  • 18. Natural Selection:• limiting factors placestresses on a population• the best adapted organismswill survive and get toreproduce and pass on theirgenes with the adaptationto their offspring• over long periods of timethis can lead to a change inspecies
  • 19. • proportionally massive eyesmaking vision acute for locatingprey• movable ears for better hearingmaking them good nocturnalhunters• can rotate their heads a full 180degrees to help them avoidpredators such as wild cats• Long back legs to help themjump twenty feet, an importantsurvival skill in the jungle• Long tail providing power forjumping and holding onto treeEx:Phillipine Tarsier
  • 20. Survivorship curves:-based on a cohort of individuals from birth untildeath-cohort=a group of individuals of the same age-survivorship curves are meant to show thenumber of individuals surviving at each agefor a particular species-three types of curves
  • 21. Type 1=good early survival, die of old age, lowbirth rates, provide lots of parental care(humans)Type 2=die at constant rate regardless of age(birds, lizards)Type3 =poor early survival,survival thatimproves withage, lots of offspring, lowparental care(fish,plants)
  • 22. Life History Patterns:r selected species: species inhabiting fluctuatingor unpredictable environments-environmentskeep populations below carrying capacity (lotsof predation, competition over resources)k selected species-species inhabiting stable,predictable environments-keep populationsize near carrying capacity and resources arescarce