Test 1 Flashcards
Teleology
the explanation of phenomena by the purpose they serve rather than by postulated cause
Fitness
relative ability to survive and reproduce
Adaptation
trait that improves the fitness of an organism
Natural Selection
the increase in the frequency of individuals with inherited traits that increase their fitness relative to other individuals
Phenotype
the characteristic morphology, physiology, and behavior of the organism
Genotype
the sum total of an organism’s genes. Determines the phenotype
Genes
a sequence of DNA that codes for the amino acid sequence that constructs a specific protein
Mutation
a random change in the DNA sequence of a gene
Population Genetics
a field of genetics that analyzes the dynamics of genes in an entire population
Gene Pool
the sum total of alleles in a population
Allele Frequencies
the proportion each allele represents in the gene pool
Hardy-Weinberg Equilibrium
a mathematical representation of the genotype frequencies of a population in which the allele and genotype frequencies are not changing (i.e.: Not evolving)
Genetic Drift
random changes in allele frequencies
Gene Flow
the net loss or gain of certain alleles by movement of individuals
Mutation Pressure
change in allele frequency due to the origin of new alleles in the population
Selection Coefficient
the proportion of a genotype that is not represented in the next generation due to death or reproductive failure
Directional Selection
a form of selection in which one tail of the bell curve is favored
Stabilizing Selection
the form of selection in which the central portion of the phenotypic bell curve is favored
Evolutionary Trade-Offs
the idea that many traits that confer a fitness advantage with respect to one aspect of the environment can also have a fitness cost relative to another
Disruptive Selection
a form of selection in which the two tails of the phenotypic bell curve are favored
Non-Darwinian Evolution
genetic drift
Effective Population Size
the subset of the total population that mates at random
Phenotypic Plasticity
the ability of an organism to produce different phenotypes in different environments
Heritability
a measure of the proportion of the phenotypic variation for a trait that is determined by additive effects of its gene
Ecotype
a genetically distinct population that is adapted to local environmental conditions
Red Queen Hypothesis
the idea that the environment changes faster than adaptations can arise by natural selection
Adaptive Landscape
a graphical representation of the fitness associated with different genotypes in a population
What did Darwin observe?
- variability of life forms
- similarities between life forms that were not located near each other
What were Darwin’s logical arguments?
- heritable variation within species
- prodigious reproductive potential of organisms
- intense competition and high mortality
Natural selection states that
individuals with inherited traits that increase their fitness will increase in frequency in the population relative to other competing individuals
What are some drawbacks in Darwin’s theory?
- mechanisms of inheritance were not fully understood
- the concept of the gene was not yet developed
- flaw of believing in blended inheritance
- other mechanisms of evolution not yet appreciated
Evolution
genetic change in a population, specifically a change in allele frequency
What is population genetics based on?
the concept of a gene pool (the sum of all alleles in a population)
What is the equation for Hardy-Weinberg?
p^2 + 2pq + q^2 = 1
Genetic drift is more pronounced in
smaller populations
Genetic drift can cause alleles to
become fixed or lost over time
Gene flow can reinforce or counteract
selection and genetic drift
Most mutation rates are ___ and most mutations are ___
low; deleterious
High mutation rate + high population size + low generation time =
rapid evolution of a serious pathogen (flu virus)
Selection increases
Darwinian fitness
Darwinian fitness
the ability of an individual genotype or phenotype to both survive and reproduce
What is the frequency before selection of AA, Aa, and aa?
AA- p^2
Aa- 2pq
aa- q^2
What is the fitness of AA, Aa, and aa?
AA- 1
Aa- 1
aa- 1-s
What is the frequency after selection of AA, Aa, and aa?
AA- p^2
Aa- 2pq
aa- q^2x(1-s)
A selection coefficient of 1 is
lethal
What does the idea of uniformitarianism say?
that modern landforms arose slowly by gradual processes rather than rapid, cataclysmic events
How can gene flow enhance or slow evolution by natural selection?
A genotype may be selected against in a population, causing their deaths. However, gene flow can enhance or slow evolution by selection. For ex., aa may be selected against, but organisms with the aa genotype can choose to leave the population to avoid death. This enhances evolution by natural selection. However, when other organisms of the aa genotype enter the population, it provides a longer period of the aa allele being present in the population. This slows evolution by natural selection.
What is the relationship between “effective population size” and random meeting?
The effective population size is the subset of the total population that mates randomly. *anything that reduces random mating reduces effective population size
Can evolution occur without a change in fitness?
yes
What is the relationship between the selection coefficient (s) and fitness?
Fitness of a genotype selected against = 1-s; this means that the frequency of the genotype is decreased by s each generation
Thermophile
organism that tolerates high temperatures
Poikilotherms
organisms whose internal temperature varies, often in response to external temperatures
Ectotherm
organism whose body temperature is determined by the external environment
Homeotherm
organism whose body temperature is regulated within narrow limits
Endotherm
organism whose internal temperature is maintained by metabolic activity
Physical (abiotic) factors
physical conditions that affect an organism’s growth and survival
Physical resources
the energy and inorganic material an organism requires
Law of tolerance
the concept that there are upper and lower bounds to the physical factors within which an organism can survive
Principle of allocation
the concept that an adaptation to one selective factor may preclude or reduce adaptations to others
Torpor
a state of decreased physiological function during periods of harsh conditions
Hibernation
an extended form of torpor
Aestivation
a period of torpor or hibernation to avoid heat and water stress
Obligate hibernator
an organism that must seasonally hibernate
Facultative hibernator
an organism that doesn’t have to become torpid but does so during harsh conditions and can arouse quickly if conditions change
Migration
seasonal movement from one region to another and back
Behavioral thermoregulation
behaviors that allow the organism to seek and use external factors such as sunlight or warm rocks to change their internal temp
Acclimation
an individual’s physiological adjustment to challenging abiotic conditions
Heat shock proteins (HSPs)
proteins that protect the organism from sudden increases in temp
Cold acclimation proteins (CAPs)
proteins that protect the organism from sudden decrease in temp
Heat
thermal energy that can be transferred from one body to another
Calorie
the amount of heat required to raise one gram of water 1*C
Specific heat capacity
the amount of heat a substance requires to raise one gram 1*C
Conduction
the transfer of heat between two bodies in physical contact
Radiation
the transfer of heat between two objects not in physical contact
Convection
the physical movement of a heated fluid (gas or liquid)
Heat of vaporization
the decrease in an object’s heat content by the evaporation of water
Emissivity
the tendency of an object to emit radiation
Absorptivity
the tendency of an object to absorb radiation
Critical temp
the max and min temp an organism can experience without expending energy to maintain a constant internal temp
Thermal neutral zone
range of temp between the upper and lower critical temp
Non shivering Thermogenesis
the use of brown fat to increase heat production
Countercurrent heat exchange
an arrangement of vessels such that the flow is in opposite directions, maximizing the temp differential between the fluids and thus maximizing heat exchange between them
Thermogenic
describes plants that can raise their internal temp above ambient
Gular fluttering
rapid throat movement in birds to lose heat by evaporative cooling
Water potential
energy gradient between two systems caused by their relative water and solute concentration. water flows from high energy to low energy
Pressure potential
the water energy due to pressure exerted as water is forced from one place to another
Turgor pressure
pressure potential caused by the influx of water to a cell with a rigid cell wall
Matric pressure
the attraction and adhesion of water on surfaces
Metabolic water
water is produced by oxidative metabolism
Xerophyte
a plant that tolerates hot, dry environments
Field capacity
the amount of water held in the soil
Permanent wilting point
when the water potential of the soil is so low that the water cannot be extracted by the roots
C4 pathway
alternate photosynthetic pathway in which carbon is fixed as a 4-carbon molecule by an enzyme with high efficiency for CO2
C3 pathway
a photosynthetic pathway in which carbon is fixed as a 3-carbon molecule by RuBP carboxylase
Photorespiration
pathway that occurs in C3 plants when the CO2 levels fall so low that RuBP carboxylase picks up O2 instead of CO2
Adventitious roots
roots produced at or above the soil surface
Shelford’s Law of Tolerance
species differ in the factors that limit their growth and in their ranges of tolerance
Beyond tolerance limits, an organisms fitness is
compromised
Principle of Allocation
adaptations and specialization have evolutionary trade offs (costs and benefits in every situation)
What are examples of small scale behavioral avoidance?
- thermoregulations
- moving to spots of more favorable temp
- basking
- modifying posture
- local stress and predator
- burrowing
- nocturnal behavior
What are examples of large scale behavioral avoidance?
migration
What are examples of metabolic avoidance?
- metabolic arrest (periods of torpor)
- aestivation (torpor to avoid heat and water stress)
- hibernation
What does high temp do to organisms?
causes denaturation of proteins and DNA
Low temperature can cause
freezing of intracellular water
Heat can be gained or lost by
- conduction
- radiation
- convection
Heat can only be lost by
evaporation of water
Heat can only be gained by
metabolism
H(total) = H(m) +/- H(c) +/- H(cv) +/- H(r) - H(e)
H(m) = metabolic heat produced H(c) = condensation heat gain/loss H(cv) =convection heat gain/loss H(r) = radiation heat gain/loss H(e) = evaporative heat loss
Plants are generally ectothermic but can influence air flow by
leaf size, shape, and orientation
What’s the difference between laminar and turbulent flow?
- laminar- moves air straight across leaf surface (inc heat loss)
- turbulent- keeps air on leaf surface, allowing for less heat loss
All biological reactions occur in
aqueous phases
Water potential =
osmotic potential + pressure potential + matric potential
The bottom of the plant has ___ water potential, water potential becomes more and more ___ up the plant to the exit
0; negative
C4 plants are only advantageous in what type of environment?
high light, high temp
Examples of osmoconformers
marine invertebrates
Examples of osmoregulators
vertebrates, freshwater invertebrates, marine crustacean
Marine fish have to deal with
high solute concentration in water compared to low internal concentration
Freshwater fish have to deal with
low solute concentration in water compared to high internal concentration
Desert animals must employ
oxidative metabolism (make their own water from sugar and oxygen)
The amount of sunlight and temperature are ___ related
directly
Vegetation
the form of the plant life in a region
Life zone
a band of vegetation associated with a specific altitude on a mountain
Geographic range
the region in which a particular species is found
Adiabatic cooling
the dec in all temperature that occur at higher elevation or altitude
Maritime climate
the climate near a large body of water usually characterized by a narrow range of temp
Continual climate
the climate in regions far from large bodies of water, usually characterized by large temp fluctuations
Mid-latitude desertification
a phenomenon in which warm, dry air is found at approximately 30N and 30S resulting in a desert climate
Rain shadow
the tendency of the lee side of mountain ranges to be drier than the windward side
Aspect
the direction a mountain slope faces
Parent material
the rock and mineral substrate underlying a region
Tree line
the altitude or latitude at which trees can no longer survive
Krumholz Growth Form
growth form of trees at high elevation characterized by a mat of branches near the ground and a single, often bare, shoot at snow level
Biogeographical realms
regions that share species and geographical history
Biome
the basic plant community types, characterized by specific vegetation, that occur in a particular region
Flora
the plant species of a region
Temperature decreases with ___ air pressure
decreased (temp decreased with altitude)
Latitude affects
the length of days, temperature, weather, etc.
Common limiting factors on the potential geographic range
- types of plants
- temp
- moisture
Actual geographic range affected by
- disturbances like fire
- biotic interactions like
- pollination
- grazing
- competition
How do tolerance limits and dispersal interact to set a species’ range limit?
tolerance limits are the primary ecological filters when it comes to range limits. They determine where an organism can and cannot live, before we factor in biotic interactions
Relationship between life zones and biomes
biomes are regions defined by specific vegetation while life zones are bands of vegetation that exist in the biomes. Therefore, biomes are determined by life zones
What are important diff. between the Gleasonian and Clementsian concepts of plant communities?
- Gleason- plant communities are random assemblages of species that happen to be in the same tolerance limits
- Clement- species of plants in areas evolved together over large periods of time
