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Ecology Part 2

Ecology Part 2. Honors Biology. Population Dynamics. Population Dynamics. Population: all the individuals of a species that live together in an area Demography: statistical study of populations, make predictions about how a population will change. Population Dynamics.

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Ecology Part 2

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  1. EcologyPart 2 Honors Biology

  2. Population Dynamics

  3. Population Dynamics Population:all the individuals of a species that live together in an area Demography: statistical study of populations, make predictions about how a population will change

  4. Population Dynamics • Three Key Features of Populations • Size • Density • Dispersion • (clumped, even/uniform, random)

  5. Three Key Features of Populations #1: Size Growth Rate: Birth Rate (natality) - Death Rate (mortality) How many individuals are born vs. how many die Birth rate (b) − death rate (d) = rate of natural increase (r).

  6. POST-REPRODUCTIVE REPRODUCTIVE PRE-REPRODUCTIVE

  7. Population of a Stable Country

  8. US Baby Boom 1970 1985

  9. Time unit Births Deaths Natural increase Year 130,013,274 56,130,242 73,883,032 Month 10,834,440 4,677,520 6,156,919 Day 356,201 153,781 202,419 Hour 14,842 6,408 8,434 Minute 247 107 141 Second 4.1 1.8 2.3

  10. #2: Density: Number of individuals ÷ Unit of space ex: 50 mice/square mile Three Key Features of Populations

  11. 4 Factors that affect density 1. Immigration-movement of individuals into a population 2. Emigration-movement of individuals out of a population

  12. 4 Factors that affect density 3. Density-dependent factors-Biotic factors in the environment that have an increasing effect as population size increases Ex.disease competition parasites

  13. 4 Factors that affect density 4. Density-independent factors-Abiotic factors in the environment that affect populations regardless of their density Ex. temperature storms habitat destruction drought

  14. Factors That Affect Future Population Growth Immigration + + - Population Mortality Natality - Emigration

  15. Three Key Features of Populations • #3: Dispersion: describes organisms’ spacing • even or uniform • clumped • random

  16. clumped even (uniform) random

  17. Population Dispersion

  18. Other factors that affect population growth Limiting factor-any biotic or abiotic factor that restricts the existence of organisms in a specific environment. • EX.-Amount of water Amount of food Temperature

  19. Other factors that affect population growth Carrying Capacity-the maximum population size that can be supported by the available resources

  20. Nu m b e r J-shaped curve (exponential growth) Carrying Capacity Carrying Capacity (k) S-shaped curve (logistic growth) Time

  21. 2 Life History Patterns • 1. R Strategists • short life span • small body size • reproduce quickly • have many young • little parental care • Ex: cockroaches, weeds, bacteria

  22. 2 Life History Patterns • 2. K Strategists • long life span • large body size • reproduce slowly • have few young • provides parental care • Ex: humans, elephants

  23. Lives 1 year Lays up to 9,000 eggs Length 20 cm Embryos develop ~ 1 month No care for offspring Safety in numbers (mating and eggs) Dramatic population fluctuations between years. Can quickly repopulate new/ unstable environments Lives 70 years Length 18 meters (male) Gestation – 15 months Calf nurses ~ 2 years Female calves every 4 years (max) Invest energy into individual offspring. Best in stable/ established environments Squid vs. Sperm Whale

  24. Human Population Growth

  25. Human Population Growth

  26. World Biomes

  27. Succession in Ecosystems

  28. Succession- • a series of changes in a community in which new populations of organisms gradually replace existing ones

  29. Primary succession- • colonization of new sites by communities of organisms – takes place on bare rock

  30. Primary succession- • New bare rock comes from 2 sources: • 1. volcanic lava flow cools and forms rock

  31. Primary succession- • New bare rock comes from 2 sources: • 2. Glaciers retreat and expose rock

  32. Pioneer organisms- • the first organisms to colonize a newsite • Ex: lichens are the first to colonize lava rocks

  33. Primary Succession- Rock

  34. Climax community- • a stable, mature community that undergoes little or no succession

  35. Climax community- • Ex: In most of Virginia, the climax community would be adeciduous oak–hickory forest

  36. Primary succession-

  37. Secondary succession- • sequence of community changes that takes place when a community is disrupted by natural disaster or human actions – takes place on existing soil

  38. Secondary succession- • Ex: • A fire levels portions of a forest

  39. Secondary succession- • Ex: • A farmer plows his field

  40. Secondary succession-

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