UA BSC 385 Exam 2 Study Guide
How can population size be determined?
1. A total census (for large organisms) 2. Lincoln (mark-recapture) methods (for small/mobile organisms) 3. Quadrat or transect methods (For sessile or relatively immobile organisms)
What are the Key Demographic Characteristics of a Population?
1. Age structure 2. Sex structure 3. Variation in individual reproduction and survival 4. Reproduction and survival can vary with age and sex
What are the 3 typical strategies by which males fight to get their genes into the next generation to the exclusion of other males?
1. Combat - direct male-male competition 2. Post-copulatory competition - prevent success of other males with female that he has mated with. (Make lots of sperm, Gaurd mates, unattractive pheromones, prolonged copulation, block other sperm, remove previous sperm) 3. Infanticide - killing other male's offspring
Subspecies/race
A local distinct form that is distinctly different in phenotype (may rarely interbreed but still are able to interbreed)
Evolutionary population
A local group of individuals that mate at random (a deme) whose boundaries are determined by the barriers to mating and gene flow
How are territory size and sexual selection related?
A male with a larger territory may attract more females
Ramet
A physiologically distinct individual within a plant genet
Stimulus-response
A specific behavior that is elicited by a specific stimulus. Often highly stereotyped (invariant)
Why are population boundaries important to determine?
Because individuals are not homogeneously distributed across the landscape
Bateman's principle
Because males compete, they experience greater variation in reproductive success than females
What is a behavioral determinant of polygyny?
Competition in males
Primary production that fuels all other marine ecosystems occurs in the ________________ zone
Euphotic
Serial monogamy
Monogamous relationship that lasts for a single breeding season
What kind of changes do Coarse-grained environments lead to?
More predictable selective pressures that favor fixed genetic adaptations
What is the formula for Lincoln methods?
N = (n1*n2)/n(m) N = total population size n1 = the number of individuals marked and released in the population at time t1 n2 = the number captured in the population at time t2 nm = the number of marked individuals at time t2
What is the formula for exponentially growing populations with *discrete* generations?
N(t) = R0^t * N(0)
What are the effects of ocean acidification on the carbon pump?
Photosynthesis fixes carbon. Then, dead organisms sink and carry carbon to greater depths. Also, herbivores and carnivores move carbon to greater depths.
Photic zone
Portion of the marine biome that is shallow enough for sunlight to penetrate.
Aphotic zone
Portion of the marine biome that is too deep for sunlight to penetrate
What is an example of a top-down biotic factor?
Predation
What are adaptations driven by?
Predation risk
Autochtonous sources
Sources of energy derived from photosynthesis within the aquatic system
What are the ecological determinants of polygyny?
Spatial distribution of females - the potential for males to control and ensure access to more than one female is dependent on spacial distribution (aggregation) of females Spacial distribution of other critical resources - If critical resources
What type of environments favor phenotypic plasticity?
Spatially and temporally fine-grained environments because they are the optimal response under variable ecological conditions
Lek-mating species
Species where males display together on traditional sites known as leks. Females choose their mate based on the displays. Few males obtain the majority of the copulations
Abundance (Nt)
The number of *individuals* in a population (Not the number of species in a community)
Density
The number of individuals per unit area or volume
Bathypelagic zone
The part of the pelagic zone that extends from a depth of 1,000 to 4,000 m below the ocean surface. It lies between the mesopelagic above, and the abyssopelagic below.
What do the results of a common garden experiments reveal?
Whether or not a difference in phenotypes within populations is genetically controlled or a result of phenotypic plasticity. If the field phenotypes persist in the common garden, the differences among populations are likely genetically controlled If the phenotypes in the common garden are similar the variation in the field is due to phenotypic plasticity
Cohort life table
A life table that follows a group of individuals over time
How is population growth linked to Darwin's theory of natural selection?
1. Each individual has a high potential reproductive rate 2. Eventually, the scarcity of resources limits population size 3. When competition becomes intense, inherent differences among individuals become an important basis for natural selection
What are the Factors that favor the evolution of ecotypes?
1. Existence of genetic variation in the trait 2. The intensity of natural selection 3. Geographical barriers to gene flow
What are the 3 fundamental components of social systems?
1. Group size and composition 2. Degree of cooperation among individuals 3. Mating system
What do the dynamics of a population depend on?
1. Immigration to the population (I) 2. Emigration from the population (E) 3. Additions to the population via births (B) 4. Losses from the population via deaths (D) N(t+1) = N(t) + B - D + I - E
What are the zones of lentic systems?
1. Littoral zone - A shallow zone in a freshwater habitat where light reaches the bottom and nurtures plants 2. Pelagic zone (Limnetic and Profundal) - Limnetic: In a lake, the well-lit, open surface waters farther from shore. Profundal: Zone in a freshwater habitat that is below the limits of effective light penetration 3. Benthic zone - The bottom layer of an aquatic ecosystem
What are the mechanisms that increase or maintain genetic variation?
1. Overdominant selection 2. Disruptive selection 3. Negative frequency-dependent selection 4. Outcrossing 5. Migration/gene flow
What are the biotic factors that affect population growth?
1. Predators (-) 2. Food supply (+/-) 3. Competitors (-) 4. Parasites (-) 5. Pathogens (-) 6. Mutualists (+)
What are the different kinds of spatial distribution of individuals?
1. Random - Individuals distributed without regard to others (Neutral interactions between individuals and with individuals and their environment) 2. Clumped - Individuals in discrete groups, positive interactions (Attraction between individuals and with individuals and their environment) 3. Regular - Individuals maintain minimum distance between themselves and their neighbors (Antagonistic interactions between individuals and with individuals and their environment)
What are the important abiotic factors in marine systems?
1. Salinity 2. Temperature 3. Light availability 4. Pressure 5. Oxygen content Most but not all abiotic factors change with depth
What are the mechanisms that decrease genetic variation?
1. Stabilizing selection 2. Directional selection 3. Inbreeding 4. Genetic drift
What do the ecological effects of temporal variation depend on?
1. The amplitude of the change 2. The speed of the change 3. Predictability
What are the 3 important aspects of environmental patchiness (spatial discontinuity)?
1. The magnitude of the differences between patches 2. The degree to which patches are isolated 3. The relative sizes of patches
What are the different types of sex ratios?
1° sex ratio: sex ratio at fertilization 2° sex ratio: sex ratio at birth or hatching 3° sex ratio: sex ratio at sexual maturity 4° sex ratio: sex ratio of the adult population
Poisson distribution
A distribution that expresses the probability of a given number of events occurring in a fixed interval of time and/or space if these events occur with a known average rate and independently of the time since the last event *Describes random dispersion*
Genet
A genetically distinct individual or clonal colony in a plant population
Continental shelf
A gently sloping , shallow area that extends outward from the edge of each continent
Survivorship curve
A graphical representation of the pattern of age-specific survival
What is a population
A group of individuals of a single species inhabiting a particular area
Ecological population
A group of individuals of a species that occupy a defined area and whose boundaries are determined by an ecologically relevant change in the environment
Black smokers
A hydrothermal vent on the ocean floor that emits a black cloud of hot, metal-rich water. The only known ecosystems where the primary producers are exclusively chemosynthetic
Static life table
A life table based on a sample of the population at one moment in time
Population bottleneck
An extreme form of genetic drift that drastically lowers the effective population size after population re-expansion follow a catastrophic event
Epilimnion
An upper layer of warm water with high levels of dissolved oxygen
Communication
Any action by one individual that alters the probability of a behavior in another Can be visual, auditory, olfactory, or tactile May convey discrete or graded information
Neritic zone
Area of ocean that extends from the low-tide line out to the edge of the continental shelf
When/how does female fitness increase?
As a function of the *quality* of the progeny, making mate *choice* important
Why is sex *NOT* an evolutionary stable strategy (ESS)?
Asexual organisms reproduced more efficiently
Why is Sex more common than asexuality?
Asexual reproduction compels genomes to be inherited as indivisible blocks
What does sexual selection result from?
Asymmetries in repoductive effort
What leads to behavioral/morphological differences in the sexes?
Asymmetries in reproductive success
How can the quantification of spatial dispersion be tested?
By comparing the actual distribution with the Poisson distribution
What is one way h^2 can be obtained in humans?
By comparison of monozygotic and dizygotic twins, which differ in relatedness by 50%
How can effective population size be saved/increased?
By restoring genetic diversity
How does the process of Ocean acidification occur?
CO2 dissolves, forming carbonic acid H2CO3. H2CO3 disassociates to form bicarbonate and hydrogen ions, lowering pH
Type 1 survivorship curve
Curves with low survival in young ages, then high survival until old age when mortality increases rapidly (many mammals including humans)
Oceanic zone
Deep water zone of the open ocean
What are some group characteristics shared by populations that cannot be applied to individuals
Density, dispersion, and age structure
Phenotypic plasticity
Development of different phenotypes in different environments *by the same genotype* Not always adaptive, changes may reflect the detrimental effects of a poor environment ex: stunted growth
Sexual dimorphism
Differences in physical characteristics between males and females of the same species.
How can population growth be estimated?
Directly from the age-specific birth and survivorship rates in a life table using a transition, or Leslie, matrix
Once mutations arise, how do their frequencies and combinations change?
Due to: 1. Meiosis 2. Natural Selection 3. Genetic drift 4. Breeding system
Type 3 survivorship curve
Early mortality is very high but decreases in older ages (Marine fishes, invertebrates, and plants)
"Truth in advertising" hypothesis
Elaborate phenotypic traits of males are an indicator of *overal* fitness. This helps females choose a superior male, thereby increasing the quality of her progeny
What is an example of a bottom-up biotic factor?
Energy and biomass available affected from lower trophic levels El Nino
Density-Independent Factors
Factors whose effects do not change with population size. i.e. weather, fire, & floods They are often unpredictable and difficult to adapt to
What are the different limiting factors on reproductive success resulting from asymmetry of eggs vs. sperm?
Females limited by the number of eggs they can make, not mates. Male limited by the number of mates, not sperm.
Polyandry
Females mate with more than one male during a breeding season
Do male or females make a larger parental investment?
Females. The mother's eggs/pregnancies are more "expensive" than producing sperm.
Haplodiploidy
Fertilized eggs produce females, unfertilized eggs produce males. Males are 75% related
What are the ecological determinants of polyandry?
Fitness benefits to females such as nuptial gifts and the reduction of the probability of mating with a poor quality male Rarest of the mating systems
How much has the mean ocean pH decreased?
From 8.25-8.14 (30% change)
Epipelagic zone
From the surface to 100-200 m; sunlight available to support primary production
Hamilton's Rule
Genes for altruism can increase in frequency if: rB-C>0 r is the coefficient of relationship of the altruist, B is the fitness benefit to the recipient, and C is the fitness cost to the altruist
What are behaviors the result of?
Genetic make-up as well as environment and experience of an individual. Few behaviors are purely genetically fixed or purely the result of the environment.
What gives rise to ecotypes
Genetically determined differences between populations inhabiting different environments
Ecotype
Genetically distinct populations adapted to local environment via natural selection
What can the relative contributions of genetics and the environment in behavior be measured as?
Heritability - The ability of a trait to be passed down from one generation to the next
What does the value of r determine?
How rapidly the population grows If r < 0, population declines If r = 0, population is stable If r > 0, population grows
What are the trends for R0
If R0 > 1, population is increasing If R0 = 1, population size is stable If R0 < 1, population is decreasing
What are the ecological determinants of monogamy
If successful rearing of the young requires both parents, monogamy is advantageous for both sexes If reproduction is highly synchronous, providing parental care is more advantageous to a male than seeking additional copulations
Biological species concept
In sexually reproducing organisms, a species is a group of populations that can interbreed and produce fertile offspring
When does male fitness increase?
In the absence of other constraints, with the number of females he inseminates
What are the trade-offs of parental investment?
Investment increases fitness of offspring, but at expense of additional offspring (i.e. lactation in mammals)
What is the function of V(a) (Variation due to additive genetic differences between individuals)
It drives resemblance between parents and offspring
What is the two-fold cost of sex?
It takes twice as many parents to produce the same number of offspring as asexual reproduction
Lentic systems
Lakes and ponds that contain zones defined by depth and light pentration
What are some major tools used by demographers to quantify age-specific patterns in populations?
Life tables and fecundity schedules
River Continuum Concept
Low-order streams usually have a higher oxygen concentration, lower temperature, more shading and higher inputs of terrestrial organic matter
Pelagic zone
Made up of photic and aphotic zones (watery part)
Balance hypothesis
Male traits are exaggerated by female choice until their overall fitness cost is too high
Monogamy
Males mate with a single female
Polygyny
Males mate with more than one female during a breeding season
Which animals does ocean acidification present a direct and significant threat to?
Marine calcifiers whose bodies are composed of calcium carbonate (corals, algae, coccolithophores, molluscs, foraminafera, pteropods)
What gives rise to phenotypic plasticity?
Non-genetic changes
Allochthonous sources
Nutrients and organic materials from the terrestrial system
What is a short summary of the Ecological "battle of the sexes"
One sex (usually males) is competitive while the other sex (usually females) is choosy
Modular Organisms
Organisms that develop repetitive patterns of growth or body parts (i.e. coral, plants)
Unitary organisms
Organisms that exist as separate and distinct individuals
The breeder's equation
R = h^2(s) Where R is the change in the trait over time, H^2 is heritability, and "s" is the selection coefficient
Mesopelagic zone
Second layer of the ocean, limited sunlight, called the "twilight zone"
Where do the most productive and diverse marine communities occur?
Shallow water near the shore i.e: Continental shelf, coral reefs, estuaries, salt marshes, and mangroves
What are the types of monogamy
Social monogamy - female bonds with one male and both the male and female share in parental care Genetic monogamy (rare) - all progeny of a socially monogamous pair is produced by the male and the female of that pair
Type 2 survivorship curve
Survivorship is constant across ages (Common in small mammals, birds, and lizards)
Dispersal
The net effects of immigration and Emigration. Best studied in large, easily observed species (lots of data)
Net Reproductive Rate (R0)
The average number of offspring produced by an individual during their lifetime
Thermocline
The boundary layer between the epilimnion and the hypolimnion where the temperature (and water density) changes rapidly
What does the response to natural selection depend on
The combination of heritability and intensity of selection
Additive genetic variation
The combined effects of all the different genes that affect fitness
What can h^2 be practically measured as?
The correlation between the average offspring phenotype and the average of the parental phenotypes
Hypolimnion
The deeper, colder layer of water in a lake or pond.
Red Queen Hypothesis
The idea that the environment changes faster than adaptations can arise by natural selection
What is true with a higher value of (F ST) (larger variation between populations)?
The larger the proportion of the total genetic variation is due to differences among populations (and the more genetically differentiated populations)
Connectivity
The link between two or more populations by dispersal of individuals
Life span
The maximum number of years an individual in the population could potentially live
Life expectancy (Ex)
The mean expectation for further life for an individual of age "x" The expectation of life at a certain age. It is affected by the probability of dying at different ages Lx = (nx + nx+1)/2
What does a transition matrix track?
The probabilities of transition from one age to another and the corresponding reproductive output that accumulates in the process
Biological pump
The process by which CO2 fixed by photosynthesis is transferred to the deep ocean
Muller's ratchet
The process by which the genomes of an asexual population accumulate deleterious mutations in an irreversible manner
Narrow-sense heritability (h^2)
The proportion of the total phenotypic variance that is due to additive genetic variance, V(a) h^2 = V(A)/[V(A)+V(D)+V(E)] V(A) = Variation due to additive genetic differences between individuals V(D) = The effect of dominance (the masking of recessive genes by dominant ones) V(E) = Environmental variation
Broad-sense heritability (H^2)
The proportion of the total variation in a phenotypic trait that is due to genetic differences among individuals H^2 = V(g)/V(p) Ranges from 0-1 V(g) = Genetic variation among individuals V(e) = Environmental variation V(p) = Total phenotypic variation
Demography
The quantitative description of the structure of populations. Includes size, age structure, sex ratios, and growth rate (i.e. vital statistics)
Fisher's Fundamental Theorem
The rate at which the mean fitness of a population increases by natural selection is equal to the additive genetic variation in fitness
Inclusive fitness
The relative ability to transfer one's genes, or copies of them, into the next generation. Fitness is based on either personal reproductive success OR that of individuals who carry copies of one's genes (i.e. siblings or cousins)
Rocky intertidal
The rocky zone occupying the area between high and low tide. It supports a diverse assemblage of plants and sessile invertebrates, which in turn support mobile invertebrates and fish. It has a strong vertical gradient of environmental conditions and temporal fluctuations of conditions due to the tidal cycles. One of the harshest environments on Earth
Mating system
The set of relationships between males and females during reproduction. This includes the number of mates an individual copulates with during the breeding season, the relative contribution of males and females to parental care, and how long the relationships between males and females last
Effective population size
The size of an "ideal population" of organisms that would experience the effects of drift or inbreeding to the same degree as the population we are studying
How is R0 determined from a life table?
The sum of the Ixbx category
How do ocean temperatures vary?
The temperatures decrease the further from the equator they are
Measuring Genetic variation
The total variation (F IT) is due to the summed effects of variation within populations (F IS) and that between populations (F ST)
How can population boundaries be determined?
Through differences in demography: 1. The number of individuals 2. Spatial distribution 3. Reproductive rate 4. Isolation vs. connectivity
What is the effect of density-dependent factors?
To regulate population size. The effects of density-dependent factors increase in intensity as the population increases
Fine-grained environmental variation
When patch size is smaller than the organism's mobility range. An organism is exposed to many environments
When will sexual selection be stronger?
When there is competition for mates
How are the actual and expected proportions compared statistically?
Using a Chi-squared test
Phenotypic variation
V(p) = V(g) + V(e) V(g) = Genetic variation among individuals V(e) = Environmental variation V(p) = Total phenotypic variation
How can density dependent factors be identified?
Via the correlation between mortality or reproduction and population density. The correlation often involve a time lag
When is the Chi squared value significant and the observed data is deemed not random?
When p > .001
Course-grained environmental variation
When patch size is larger than the organism's mobility. An organism experiences one or a few environments over its lifetime
How do we measure genetic variation in populations?
With common garden experiments - individuals with different phenotypes in the field are grown under similar conditions
How is the expected proportion of squares (Px) with "x" individuals calculated?
With the formula: Px = (a^x * e^-a)/x! Where a = the mean occurence per grid square If x = 2, x! = x(x-1)(x-2)
Can habitat quality affect survivorship curves?
Yes.
Do behaviors contribute to fitness?
Yes.
Do survivorship curves differ between sexes?
Yes.
Alarm call
a vocalization that warns other colony members of a predator's presence but greatly increases the risk to the caller i.e.: Belding's ground squirrel
What happens when N = 0?
dN/dt = 0; the population is stable
What is the formula for exponential growth?
dN/dt = rN r = (b+i) - (d+e)
What is the formula for Logistic Population Growth?
dN/dt = rN * (K-N)/K K = carrying capacity
What happens when N > K?
dN/dt is negative and the population declines
What happens when N < K
dN/dt is positive, the population grows
Abyssopelagic zone
the 4,000-6,000 m depth zone, seaward of the shelf-slope break
How is the exponential growth of overlapping generations calculated?
via N(t) = N(0) * e^rt r = instantaneous growth rate (b(0) - d(0))
Sexual selection
when individuals select mates based off heritable traits. These traits may improve reproductive success but also may reduce survival at the same time (i.e. Collared lizards)