Unit 1 Flashcards
(21 cards)
Compare r-selection to k-selection
r-selection
- Characterized by unstable habitat
- smaller body sizes
- shorter lifespans
- early age of first reproduction
- number of reproductive episodes are once or few (semelparity)
- large clutch size
- little parental care
- mortality high initially
k-selection
- More stable habitats; fewer extremes that occur less often
- larger body sizes
- longer life span
- later age of first reproduction
- many reproductive episodes (iteroperity)
- much smaller clutch sizes
- condiderable parental care
- mortality low initially
List the characteristics of a population
- Possess a spatial boundary (range)
- Exhibit a distribution (biogeography)
- Possess a temporal boundary
- Dispersion patterns
- Exhibit a charaxcteristic life history pattern
- Possess a definate population size (N) which fluctuates from season to season
- Possess a genetic structure
- ecological niche
List and describe the differnet distributions (biogeographies)
- Cosmopolitan - found all over the world
- Circumpolar - found near the poles
- Native species - found in a geographic area and is well established.
- Endemic - found only in one spot in the world
- Disjunct - main population found ina specific area but also isolated populations found way out of the main population
- Non-native species - species that have been removed from their environment and transfered to some place else. These species can become invasive.
list the 3 types of dispersion patterns
- Uniform - territoriality
- Random - Solitary species/ environmental hetergeneity
- Clumped - Sociality / environmental hetergeneity
Life history patterns consist of what 5 characteristics
- life span
- mating systems
- growth rates
- survivorship curves
- fertility schedules
List and describe the 3 types of survivorship curves
- Type 1 - small clutch size with high survivability early on
- Type 2 - steady death rate throughout life span
- Type 3 - large clutch size where many die early in life
one type of allelle per characteristic; no variation in allelles
monomorphic
two allelles per characteristic
dimorphic
no limit to the number of allelles per characteristic
polymorphic
The sum total of all the interactions with both the living (biotic) and non-living (abiotic) components of the environment are described by ______________
an ecological niche
compared exponential growth with arithmetic growth
“…misery and vice…”
Thomas Robert Malthus
A homogenizing force that erases differences within the populations
geneflow
A single large population is subdivided or fragmented into two or more subpopulations
allopatric speciation
A small subset of the population leaves, or migrates thereby removing Their alleles from the “parent” population.
founder affect
random, unpredictable changes in population
genetic drift
List the two ways in which a population can evolve
- Natural selection - non-random changes that result from selective pressures acting on variation in a population and that not all of the variation is equal. natural selection is adaptive; selecting only those variants that increase fitness
- Genetic Drift - random, not adaptive – it is simply chance.
An event eliminates most of the population. Initially there is a high mortality and individuals continue to be lost from the population until it reaches its’ minimum size. Most of the genetic diversity that was present earlier has now been lost.
bottle neck
When genetic isolating mechanisms are incomplete genes/alleles of one species may make their way, through hybridization, into another species.
Introgression
Population genetics; states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.
Hardy-Weinberg Equilibrium
p + q = 1.
the change in allele frequencies that occurs over time within a population
microevolution
change that occurs at or above the level of species
macroevolution
