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POPULATION DYNAMICS

POPULATION DYNAMICS. Chapter 8 pp 197-202. What is a POPULATION ?. definition. All the members of a species living in the same place at the same time and breed with each other May show GENETIC DIVERSITY. A school of glass fish in the Red Sea The field mice living in a corn field

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POPULATION DYNAMICS

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  1. POPULATION DYNAMICS Chapter 8 pp 197-202

  2. What is a POPULATION ? definition • All the members of a species living in the same place at the same time and breed with each other • May show GENETIC DIVERSITY • A school of glass fish in the Red Sea • The field mice living in a corn field • Monarch butterflies clustered in a tree • Palm trees on a tropical island examples

  3. POPULATIONS

  4. GENETIC DIVERSITY

  5. PROPERTIES of a POPULATION • SIZE- the number of individuals • DENSITY- the number /area • DISPERSION-relative distribution • AGE STRUCTURE- proportion in different age groups

  6. POPULATION DYNAMICS • Studies the interaction of these characteristics of a population with their environmental conditions

  7. POPULATION SIZE • INCREASES 1- more births 2- immigration • DECREASES 1- more deaths 2- emigration

  8. POPULATION DENSITY • DENSITY DEPENDENT Factors that effect the population due to how crowded they are, ex: Disease Finding a mate/food/shelter Predation Human harvesting • DENSITY INDEPENDENT Factors that effect a population that do not depend on how crowded they are, ex: Severe weather Natural disaster Habitat destruction

  9. POPULATION DISPERSION • CLUMPS/PATCHES- most populations live in groups or patches, ex: desert vegetation near a spring a wolf pack flocks of birds

  10. Why CLUMPING? 1- gather near their resources 2- easier to find food in a group 3- protection from predators 4- helps predators get food 5- help in finding a mate/care for young

  11. Other patterns of dispersion UNIFORM • SOME SPECIES MAINTAIN A FAIRLY CONSTANT DISTANCE BETWEEN INDIVIDUALS ,ex: creosote bushes • A fairly rare method of dispersion where individuals are spread out with no definite pattern RANDOM

  12. AGE STRUCTURE • The proportion of individuals at various ages • Used to predict future growth of the population

  13. HOW DOES A POPULATION GROW? CHANGE IN POPULATION = ( Birth Rate + Immigration) - ( Death Rate + Emigration)

  14. Growth Rate • Positive (+) if BR/IMM > DR/EM • Zero (0) if BR/IMM = DR/EM • Negative (-) if BR/IMM < DR/EM

  15. How fast can a POPULATION GROW ? • BIOTIC ( reproductive) POTENTIAL -the fastest rate at which a population can grow • Each individual has the maximum number of offspring possible • - depends on reproductive pattern of individual

  16. BIOTIC POTENTIAL • ELEPHANTS- one offspring every 2 years • In 750 years there will be 19 million elephants • BACTERIA- double in minutes • In a few days or weeks there will be 19 million bacteria

  17. Sea Turtles vs. Songbirds p 199

  18. Why don’t populations reach their biotic potential? • Environmental factors restrict unlimited population growth , ex: • Food • Mates • Living space/habitat Exponential growth- J Curve

  19. CARRYING CAPACITY • The maximum population the ecosystem can support indefinitely • Levels off • May change seasonally • Tempered by environmental resistance (LF) Logistic Growth- S curve

  20. Are Humans exempt from population control? • We control our environment : TECHNOLOGYFOOD PRODUCTIONMEDICINEIMPROVED SANITATIONEDUCATION • Irish potato Famine • Bubonic Plague • AIDS • Genocide

  21. Math Practice p 201

  22. Math Practice p 201

  23. Math Practice p 201

  24. Math Practice p 201

  25. Homework : Reindeer POP

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