Quiz 3 Flashcards
Population ecology
Studies the factors that regulate population abundance and distribution. Information from tracking is studied
Low population density
Individuals may not be able to find mates or only mates that are closely related. Flocking, genetic variability = dependent on density
High population density
Competition for space, food, mates spread of disease increases
Population age structure
Relative number of individuals of different ages within a population
Clumped distribution
When social species such as wolves, elks and praire dogs are found in groups
Random Distribution
Species that disperse randomly in an environment like wind-blown seeds
Uniform Distribution
Individuals spaced evenly possibly due to territorial behavior or something that suppresses growth
biotic potential
A population’s maximum per capita rate of increase (r)
Variables in patterns of population growth
Resource availability, aggression/competition, predation
Logistical Growth
Population size increases, while growth rate decreases
Carrying Capacity
Population size that can be sustained indefinitely without long-term damage to the environment
Limiting Factors
Resources needed for survival but that may be in short supply. Scarcity depends on carrying capacity
Resistance Factors
Predation, competition, and diseases - their relationship with population size
Limiting and Resistance Factors are _____, while natural disasters are ____, because they will occur regardless of the population size
density-dependent, density-independent
K-selected species
slow increases and decreases in response to the environment
r-selected species
Sometimes have sudden population growth with high peaks which may overshoot carrying capacity, drop below it and increase and overshoot it until they settle down close to carrying capacity.
loss of wolf in ecosystem
without wolves, beavers thrive and build dams that create lakes and ponds. Elk stay in the willow thickets and overgraze willow needed by the beavers
Primary cause for species to become endangered
Habitat destruction
Characteristics of r-adapted species
short life, rapid growth of individual, early maturity, many offspring, little parental care, adapted to unstable environment, prey, niche generalists
Characteristics of k-adapted species
long life, slower growth of individual, late maturity, few offspring, high parental care, adapted to stable environment, predators, niche specialists
Species
A group of pollutions or pollution of a type of organism whose members share common characteristics and can breed together
Darwinian Theory
Science is all about forming hypotheses and finding evidence that supports or conflicts them
Lamarckian Inheritance
organisms could change from generation to generation. Used and needed traits were made stronger and passed on
epigenetics
suggests that environment can play a role in expressed traits
Evolution
Change in genetic characteristics of a population over time
Natural selection
Explains how evolution occurs
Phylogenetic Trees
Geological relationship between species
Scientific name
An organism’s genus and species designation
Overproduction
Organisms are capable of making large numbers of offspring
Heritable Variability
Offspring vary in their appearance and function (genetic variation)
Differential reproduction
Survival and reproduction = not random. Individuals that can better compete for resources will leave more offspring
Genes
Physical locations on chromosomes that are code for inherited traits
Alleles
When a given gene exists in two or more forms
Genotype
The complete set of genes in an individual
Phenotype
The set of traits physically expressed in an individual
Mutations
Alterations in DNA sequences during replication
Adaption
A trait that increases the fitness of an individual in a particular environment
Fitness
Tendency for a trait to increase or decrease the population
Example of evidence of natural selection
sickle cell anemia - heterozygote individuals of this trait = less likely to get malaria
Macroevolution
the real origin of a species
Microevolution
Changes within a species with among members who are still considered part of the same species
Speciation
The separation of two previous interbreeding populations in which the two can no longer produce fertile offspring
Subspecies
Organisms of the same species that are capable of breeding
Genetic Drift
Pure chance and random mating can increase or decrease the frequency of a trait
Bottleneck effect
Part of the population dies suddenly, leaving the survivors to produce a new generation
Founder effect
A small group that contains only some of the original variants colonizes a new areas
