Biology Final Flashcards
Population structure
Defined by patterns of mortality, age distributions, sex ratios, dispersal.
Suvivorship curve
Summarizes pattern of survival in a population
Life tables
Bookkeeping device to track births, survivorship, and deaths in populations
Cohort life table
Identify individuals born at same time and keep records from birth (easy to interpret, but often difficult or impossible to collect these data)
Static life table
Record age at death of many individuals over narrow window in time (requires accurate estimate of age at death)
Age distribution
Calculate difference in proportion of individuals in each age class (assumes differences in numbers from one age class to next due to mortality and assumes population stable in size)
Sex ratio
Relative frequency of each sex type in population.
Empirically, find most populations have sex ratio near 1:1
BIDE
Birth -any process that produces new individuals in the population Death Immigration into population. Emigration out of population.
Density-dependent factors
Influenced by population density (e.g. competitors, predators, disease)
Density independence factors
Do not vary with population density. e.g., floods, extreme temperatures
Fecundity schedule
Birthrates for females of different ages
Net reproductive rate (R0)
Average number of offspring produced by an individual in a population per generation
Generation time
Average age at which female gives birth to offspring (i.e. time it takes to go from seed to seed or egg to egg)
Logistic population growth
Exponential growth curve modified to include biotic limitations on population growth
Intraspecific competition
Among members of the same species
Interspecific competition
Among members of two species
Resource limitation
Limited resources, space, etc. leads to interference competition and exploitative competition
Interference competition
Direct aggressive interaction between individuals
Exploitative competition
Competition to secure resources first
Competitive exclusion principle
Complete competitors cannot coexist
Fundamental niche
Range of conditions under which species can survive
Realized niche
Range of conditions under which species typically found
Character displacement
Competition between species living together (sympatry) can evolve differences between them, though they are nearly identical living apart (allopatry)
Exploitation
Interaction between populations that enhances fitness of one individual while reducing fitness of the exploited individual
Herbivores
Consume live plant material but usually do not kill plants
Predators
Kill and consume other organisms
Constitutive (plant defenses)
Produced continuously, regardless of environment
Induced (plant defenses)
Increase rapidly in response to herbivore damage
Consumptive effects
Direct effects of predation on prey populations through capture and consumption of prey
Non-consumptive effects
Changes as consequence of predator presence, even when prey not killed (e.g. high blood cortisol levels known to increase with stress and shifts in morphological traits, stress-physiology, altered behaviour)
Aposematic colouration
Bright colouration in prey that advertises fact prey have toxin or are distasteful in some way
Müllerian mimicry
Several species of toxic/noxious animals share similar warning colouration. This can enhance learning by predators, thereby reducing predator risk for mimics
Batesian mimicry
Nontoxic species exhibits colouration similar to that of noxious species living in same area
Symbiotic relationships
Organisms which benefit one another live in close proximity to each other
Mutualism
Interactions between individuals of different species that benefit both partners
Facultative mutualism
Species does not require mutualistic partner for survival
Obligate mutualism
Species is dependent on mutualistic relationship
Disease
Atypical condition in living organism that cause some sort of physiological impairment
Community
Association of interacting species inhabiting some defined area
Community structure
Includes attributes such as number of species, relative species abundance, and species diversity
Guild
Group of organisms that make a living in similar way
Species diversity
A combination of the number of species and their relative abundance
Species richness
The number of species found within a community is one of the most fundamental aspects of community structure
Alpha diversity
Measure of local diversity
Beta diversity
Measure of the differences among communities within the region or landscape
Gamma diversity
Measure of regional or landscape diversity
Dominance
One or a few species are substantially more abundant than other species in community
Species richness
Number of species in the community
Species evenness
Relative abundance of species. Can be thought of inverse of dominance
Ecological services
Processes and resources of value to humans provided
by ecological systems. These processes and resources are typically called ecological functions
Ecosystem function
Process within an ecosystem such as biomass production, nutrient cycling, or carbon sequestration. If function is diminished, so too is the quality of the service
