Population Genetics Flashcards
(26 cards)
Population dispersion
refers to the general pattern in which individuals are distributed through specific area
Clumped dispersion
Favourable conditions for survival and social behaviour
Uniform dispersion
- Competition for feeding, breeding or nesting territory
- less common in nature
Random dispersion
- rare in nature, minimal influence or interaction with other individuals
- Habitat conditions are virtually uniform
Changes to population numbers
1 Mortality (m) 2 Emigration (e) 3 Natality (n) 4 Immigration (i)
Biotic potential
- The maximum number of offspring that can be produced when there are no restrictions
- An organism reaches its biotic potential and there is unlimited food, water etc.
conditions for hardy weinberg
The population is infinitely large No migration occurs no mutation occurs No natural selection occurs mating is random
founder effect
When individuals from a large population leave to establish a new population, The resulting genetic drift is called a founder affect
bottleneck effect
When a random, severe environmental event Result in a drastic reduction in population size ( and genetic drift ) it is known as a bottleneck affect
gene flow
The movement of alleles from one population to another through the movement of individuals or gametes
natural selection vs mutations
Mutations provide a source of variation, but natural selection ask on individuals and their phenotypes
Exponential growth (J shaped)
Lag face - at the beginning the population is small so growth of his population is slow but as the number increases the population will experience an exponential rate of growth
Exponential growth demonstrates growth limited only by biotic potential
Carrying Capacity
-Is a limit to the number of individuals that an environment can support at any given time
Logistic Growth (S shaped)
- Eventually competition for resources will slow the rate of growth
- Limited by carrying capacity but just a growth is most like the population growth seen in a wild population
K selected species
- How do you offspring per cycle/Take a long time to mature/live a long life and usually larger in size
- Numbers stay close to the carrying capacity
- Display an S shaped logistic graph
R selected species
- Organisms that have a high biotic potential, like insects
- Short lifespan, early reproductive age, produce lots of offspring
- Their population spike and then have a drastic drop (J shaped curve)
density dependent factors
a factor that influences a population at a particular density
ex. disease/ intraspecific competition/ predation
density independent factors
a factor that has the same influence on a population at any population density
ex. habitat destruction/ natural disasters/ human action
limiting factors
-Of all the resources that a population requires for growth, the resource in shortest supply is called the limiting factor, and it determines how much the population can grow
exploitative competition
consumption of shared resources, one species monopolizes the resource
competitive exclusion
the concept that, if resources are limited, no two species can remain in competition for exactly the same resource indefinitely
defense mechanisms
morphological - horns spikes etc
mimicry- looks like another animal to scare away
succession
slow, progressive replacement of one community by another during development of vegetation in the area
primary succession
plant life in area not previously covered by vegetation
