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6)Population ecology
Biology Revision 2
Question | Answer |
---|---|
What are the 3 types of population dispersal? | 1)Clumped (like sheep and carabou, they live together) 2)Uniform (like trees, uniform spacing) 3)Uniform environment (no advantegous places, depends on where it was randomly placed), |
What is a metapopulation? | The population doesn't occupy all of the range (all of its territory all the time), like carabou who are nomadic |
What is the special type of metapopulation? Example? | A population entre (source) send emigrants out to surroinding areas (sink). The source is where they breed and the sink is where they die. Ex: Glanville Fritillary butterfly |
Does every specie have the same type of dispersal? | No, all different |
What is the population demography diagram? | Inputs (Births+Immigration)--» Population --» Outputs (Deaths+Emmigrations) |
What is the tendency with large organisms? | Larger organisms have longer generations like elephants, so population grows less rapidly |
What are the 3 types of survivorship curvatures? | Type 1) Low death rate during early stage then increases with od age like humans Type 2) Constant chances of dying at any age (squirrels) 3)High death rate for young and slower death rate when old (shell) |
What's the relationship between survival and reprodution? | More offsprings=Less chances of survival bc lots of energy used taking care of them. So, if reproduction increases, survival and production might decrease. |
What is exponential growth? | It's the biotic potential of a species . Population growth is density independent. It's when there's no growth limit to population, it increases rapidly. Ex: Fruit flies or bacteria |
What is the carrying capacity? | When resources run out and exponential growth stops or slows. Basically, the carrying capacity (K) is the max number of individuals an environment can support. |
What is logistic growth? | When population reaches its carrying capacity (max amount of ppl is reached for an environment), its exponential growth slows and becomes logistic growth. Population growth is density dependent. |
Relate homeostatis and the environment | Individuals try to maintain homeostatis in the face of a changing environment |
How does a life table work? | Life table follows a population to understand the impact of death and reproductive on its population. See the numbers as fraction to understand the data, for example, 1.98 in fecundity X survivorship means population doubled! |
Give examples of species with their survivorship curvature | Type 1: Humans, elephants, lions Type 2: Squirrels, hydra Type 3: Oysters, trees |
What are density independent factors (that affect population growth)? | Cold, earthquakes, shortage of water (drought). |
What are density dependent factors (that affect population growth)? | Competition, toxic waste, predation, disease, intrinsic factor (stress hormone) |
What are the two types of life history? | Semelparity- One reproductive event in lifetime, many offspring (so lots of babies and no investment in them) like Mayfly. Iteroparity- Many reproductive events in lifetime, few, large offspring that are taken care off. |
What are K and R populations? | K selected have longer lifespan, maturation time, and many reproductive events. they have larger offsrpings who are taken care off. R selected is the contrary (No care, short life-span, high mortality rate,...) |
What is population growth (dynamic) affeted by? | (1) Generation time (time it takes to mature) and (2) Sex ratio (Male can fecondate many females,but females can only have one baby at a time) |
Just remember what a age structure (population pyramid) is | Age in Y and % of population in X. Separated by sexe often. If pyramid is rectangular, population is stable. |