study of the distribution and abundance of organisms and the interactions (abiotic and biotic) that determine distribution and abundance
group of individuals of a single species inhabiting a specific area.
a group of subpopulations living on patches of habitat connected by an exchange of individuals
size, shape, and location of the area it occupies and the spacing of individuals within that area
total number of individuals or biomass
number of individuals or biomass per unit area
Other characteristics for Characterizing populations
birth-death rates, age distributions, immigration and emigration, rates of growth
the population is the unit of evolution!
Organisms require particular sets of
abiotic conditions to survive and reproduce
Examples of abiotic conditions
temperature, pH, salinity, and the forces of wind or waves
Organisms also need -------- to survive and reproduce
quantities of resources can sometimes be reduced by
the activities of the organism, promoting competition for limited resources
Examples of resources
solar radiation, carbon dioxide for plants, water, oxygen, and food items
refers to the sum total of an organism's tolerances and requirements
describes where an organism lives
n-dimensional hypervolume (what is n?)
where n equals the number of factors important to the survival and reproduction by a species
G. Evelyn Hutchinson
proposed the modern concept of the niche in 1957
The full range of environmental conditions (biological and physical) under which an organism can exist
The conditions under which the organism actually survives, grows and reproduces. Interactions with other organisms (e.g. superior competitors), usually force a species to occupy a niche that is narrower than the fundamental niche
The complete niche for all possible environmental variables is a
multi-dimensional hypervolume---with axes for each variable, making it impossible to visualize
involving or serving as an aid to learning, discovery, or problem-solving
The niche should be seen-----------------------rather than the environment
as a product of the organism
a local scale example of what affects a population's distribution/abundance
Balanus cannot exist in the upper intertidal because of higher mortality
what affects distributions/abundance at broader scales (i.e., what is the distribution of populations for a species across a range.)
The tiger beetle, Cicindela longilabris, is confined to cool environments
the spatial location of organisms in a population. There are two areas to consider in describing distribution: the boundary and patterns within the boundary Affected by both biotic and abiotic factors. look at diagrams------
Example of what might affect distribution patterns
Creosote bush in Sonoran and Mojave deserts Patterns vary at different life stages look at diagram--------
Population density declines with
increasing organism size
Factors that influence the expansion (growth), decline (extinction), or maintenance of populations (Equation)
Nfuture = Nnow + B (births) - D (deaths) + I(immigrants) - E (emigrants)
IF B + I = D + E, then
Nfuture = Nnow The population size is constant and the population is at equilibrium
A point at which there is no net change in the system (when the population is at equilibrium, each adult produces an average of one offspring that survives to adulthood)
IF B + I < D + E, then
Nfuture < Nnow The population size is declining and unless something changes, the population will go extinct.
IF B + I > D + E, then
Nfuture > Nnow population size is increasing, and the population will continue to grow without bounds. Can that actually happen? (not really)
age (or stage) structure
distribution of individuals among age classes Age distribution of a population reflects its history of survival, reproduction, and potential for future growth
Life Tables are a simple tool for keeping track of------of interest
births, deaths, and reproductive output in a population
Three ways to generate life tables
Cohort (horizontal) life table, Static (vertical) life table, Static life table based on mortality records.
Cohort (horizontal) life table
follows a group of same-aged individuals from birth (or fertilized eggs) throughout their lives. Assumes all cohorts have same pattern
Static (vertical) life table
made from data collected from all ages at one particular time (less accurate and has 2 assumptions) 1) proportion of individuals in each age class does not change from generation to generation (stable age distribution), 2) the population size is, or nearly, stationary
Static life table based on mortality records
as above but based on age of dead organisms (e.g., skulls of moose)
Survivorship curves (3)
type I- juvenile survival high, death occurs more later in older age. type II- die at equal rates regardless of age. type III- die at high rates as juveniles and much lower rate later in life.
proportion of original cohort surviving to stage x (lx = nx / n0)
average number of offspring per individual of stage x
R0= Σ lxmx *Net reproductive rate--, the average number of offspring produced by an individual in a population over its lifetime
1 stable population; >1 population growing; <1 population declining can also calculate R0 as λ = Nt+1 / Nt (λ is the geometric rate of increase)
generation time, average time from egg to egg, seed to seed, etc (also x
What else can we calculate from a life table?
Per capita rate of increase (r)
(ln R0) / T (ln is the natural logarithm of R0) r as the birthrate minus death rate (r = b - d) r = 0, population stable; >0, growing; and <0, decreasing
tell us about the ages or stages at which organisms are most likely to die (survivorship curves)
tell us at which ages or stages individuals make the greatest contribution to the next generation
Life tables and fecundity schedules require 3 measurements
age (or stage), fate (alive or dead), and offspring number
Together, life tables and fecundity schedules can
-provide estimates of R0, λ, T, and r -help predict and manage population growth
Two key aspects of a life table-------and-------,form a foundation for natural selection.
survivorship and fecundity
Growth models enable us to predict
rates and patterns of population growth and what factors limit population sizes.
In the presence of abundant resources,
populations can grow at geometric or exponential rates.
Geometric growth model
for organisms with discrete breeding seasons, also called pulse breeding (e.g., Phlox drummondii)
for organisms with continuously breeding populations (e.g., humans)
λ = Nt+1 / Nt Nt+1 = Nt * λ :general formula to get pop. size from one generation to the next Nt = N0λt :general formula to model the size of a population growing geometrically at any time t. Nt = N0Rt if non-overlapping generations and pulse breeding
For continuously reproducing organisms with overlapping generations, we need to consider
instantaneous rates of increase.
is geometric growth with the interval between growth increments reduced to zero.
is the interest rate in Nt = N0 (1+r)t In biological terms r = intrinsic rate of increase
compounded q times per year
Nt = N0 (1+r/q)qt
q = infinity, Nt = N0 (e)rt , where e is the base of the natural logs, which is equal to 2.71828
Do we see exponential growth in nature
suggest about exponential growth
It may be important to populations during establishment of new environments, during the exploitation of transient, favorable conditions. during the recovery after a major decline.
These are all conditions during which resources or space are not limiting!!!!!!!
Nt = N0 (e)rt
Nt = N0λt
The most important population parameter for exponential growth is
r. r = 0, population stable; >0, growing; and <0, decreasing R0 = λ = 1 stable population; >1 population growing; <1 population declining
differential form of Nt = N0 (e)rt is
dN/dt = rN = (b-d)N
instantaneous birth rate
instantaneous death rate
rate of change in population size
rate of change in time
instantaneous rate of population increase
Important aspect of exponential growth is that as population size (N) increases
rate of population increase (dN/dt) gets larger.
Multiple factors may limit population growth
Declining birth rate or increasing death rate The regulation of growth in a natural population is determined by biotic and abiotic factors such as: limited food supply or space the buildup of toxic wastes increased disease predation competition weather conditions
Thomas Robert Malthus (1798)
An Essay on the Principle of Population Written in a time when many believed in the possibility of almost limitless improvement of society greatly influenced Charles Darwin
Pierre-Francois Verhulst (1838) published an equation
the logistic equation.
As resources are depleted, ...................... and eventually stops. This has been called..................................
rate of population increase slows down, logistic population growth.
Population size at which growth stops is called
carrying capacity (K)
carrying capacity (K)
which is the maximum number of individuals of a population that an environment can support.
K, b = d, so population size is
= rN [(K-N)/K) = rN [1-(N/K)]
r v realized =
Some assumptions of logistic population growth
No migration - dispersal can be important and may keep a population with negative r from going extinct
Constant K (constant environment over space and time) - K is likely to change over both space and time
All individuals are equal, each using 1/Kth resources (e.g., assumes no age differences)
Humans obviously have a major influence on
the global environment.
Where are people distributed? For most part, current distribution reached
10,000 years ago and did not need technological advances (except islands and Antarctic).
Age structures vary among countries.
Can infer population growth from age structure.
Growth varies among countries.
Can predict future population sizes.
- broad base - many young - rapid population growth
- narrow base - few young - population decline
Aspects of an organism's biology such as the
number of offspring it produces, survival, its size and age of reproduction
a trait that has arisen via natural selection.
dN = rate of change in population size
rate of change in population size
Modes of reproduction sexual
zygote formed as a fusion of two gametes (involves meiosis, thus recombination) Disadvantages: need to find a mate, only provide 50% of offspring's genes Advantages: offspring are genetically diverse
individual organisms are a single sex
Monoecious - Hermaphrodite
individual organisms are, at some time during their lives, male and female (many plants, most flatworms are simultaneous hermaphrodites, whereas wrasses are first female than male - sequential hermaphorodite)
- unisexual reproduction producing genetically identical offspring. Advantages: no need to find a mate, all genes transmitted to all offspring; offspring phenotype already successful in that environment Disadvantages: all offspring vulnerable to same enemies and all offspring respond in same fashion to change in environment (physical or biological) - no "spreading of risk"
If organisms use energy for one function such as growth, the amount of energy available for other functions is.................
Leads to trade-offs between functions such as ............ ..................
number and size of offspring.
Organisms often go through a series of
-developmental stages over their lifespan. ex. :When should one reproduce and when should one shift environments or migrate
Life cycle examples on pp
check on slides
Some patterns and trade-offs -during reproduction
Body size and number of offspring
Some patterns and trade-offs -2nd property
Offspring number versus offspring size
Some patterns and trade-offs property 3 Life history also related to dispersal because ....
-migration also affects population sizes
Offspring size and dispersal
Some patterns and trade-offs property 4
Offspring size may affect survival
When should you reproduce? Low adult survival, reproduce .......... High adult survival .................... ......................
-reproduce earlier -defer reproduction and invest in growth
Individuals only have a single, distinct period of reproductive output in their lives. They devote most of their early life to growth, and die shortly after reproduction.
An individual normally experiences several or many reproductive events. During each reproductive event, the individual continues to invest in survival and possibly growth. Most individuals survive to reproduce again after a given reproductive episode.
Broadly classifying life history strategies r and K selected species
r k Mortality (Variable/unpredictable) (More constant predictable)
Pop. Size Variable, below K Constant, close to K
Life span Usually shorter Usually longer
r species tend to
maximize high productivity
K species tend to
From an ecological point of view I want you to understand that resources need to be ............... ................. ...............
allocated to growth and reproduction of an organism.
What Controls Population Size and Growth Rate (dN/dt)? Density-independent factors
disturbance, environmental conditions -hurricane -flood -colder than normal winter
Intra-specific competition -food -space Contagious disease Waste production *Interspecific interactions
- between species
- live in intimate contact
species: 0 to 0 affect
- to 0
+ to 0
- to -
- to +
+ to +
Occurs directly between individuals via aggression
etc. when the individuals interfere with foraging, survival, reproduction of others, or by directly preventing their physical establishment in a portion of the habitat.
- Occurs indirectly through a common limiting resource which acts as an intermediate.
For example the use of the resources depletes the amount available to others. (Limiting resource - a resource that constrains population size)
intra and interspecific examples on slide
How can we determine the realized niche of each barnacle?
Where do they grow when allowed to compete? look at graph
How can we determine the fundamental niche of each barnacle
Removal experiments - remove each species and see where the other grows look at other graph
The...... of a species may contract in the presence of a ........... ............
niche, competitor species.
This phenomenon leads to ........ and .......... among functionally similar species.
resource (niche) partitioning and coexistence
The narrower niche resulting from competition is called
the realized niche.
competitive release -
niche of the competitively-inferior species expands in the absence of the competitively-superior species
ignore m, wasn't on slide
What is K?
Is the carrying capacity. k is the max number of individuals of a population than an environment can support.
another factor that can limit the abundance of a species
read on donuts example
Possible outcomes when put two species together.
Species A excludes Species B Species B excludes Species A Coexistence
more equation formulas on pp 9
look on slides
When N1 = 0
K1/α12 = N2 Population size of 2 at which species 2's use of species 1's resources = K1 individuals
When N2 = 0
K2/α21 = N1 Population size of 1 at which species 1's use of species 2's resources = K2 individuals
Isoclines cross, but neither species can
reach level at which outcompetes the other—intraspecific limitation more powerful
The critical things to recognize are when this value is greater than the species own K and when the isoclines cross.
For this look on slides for example.
Predicts species can coexist when intraspecific competition stronger than interspecific
Assumptions of Lotka-Volterra Model
These models assume logistic growth
Species are near equilibrium (i.e., zero rate of growth)
α is constant
Temporal or spatial heterogeneity can alter outcomes
- plant eaters, algae not usually considered but included
- meat eaters (other carnivores or herbivores)
Cannibalism - eating one's own species - a specialized form of predation
- eating one's own species - a specialized form of predation
- usually insects that lay their eggs on other insects as hosts. The larvae complete development on the host, usually killing the host as a result .
- feeding on another organism's parts without killing the organism (a note: parasitism is very widespread among phyla and has evolved many independent times)
a relationship between individuals of two different species in which individuals of each species live in continual contact
mutualisms may or may not be symbiotic
ex lichen fungi and lichen algae are only found together - symbiotic plants and pollinators are only in contact when the pollinator is feeding - not symbiotic
parasitic interactions may or may not be symbiotic
ex parasitic tapeworms can only grow and reproduce in the gut of a vertebrate and only leave one host to get to another - symbiotic mosquitoes spend as little time on their hosts as possible (for obvious reasons) - not symbiotic
Relationship between two organisms that benefits both
mutualisms carry both costs to each partner and benefits as well
mutualisms are favored when the benefits are greater than the costs, so it is the net benefits (or benefit cost ratio) that determine the outcome of these interactions
2 types of mutualism
- organisms cannot survive in the absence of the other partner
- organism can lead an independent existence
Examples of Mutualism relationships
Pollination - plant gets pollen transfer and pollinator gets food
Cleaning - cleaner shrimp eat ectoparasites off fish
Defense - one gets food/shelter other gets protection -ex: -Ants-acacia system
-Plants-nitrogen fixing bacteria
-Bacteria- aphids, lichens (algae and fungi)-- both obligate
-Plant - Mycorrhizae (facultative except for orchids)
Association of interacting species inhabiting some defined area.
Community Structure includes attributes such as .....
number of species, relative species abundance, and species diversity.
Group of organisms that all make their living in the same fashion.
E.g., all the seed eating animals in an area (can be composed of different taxa).
-*number of species in a community
-very simple, so easy to get but not much info -problem—number of species depends on size of sample -correct with rarefaction
measures use more info than species richness
What does diversity mean?
How measure diversity?
Richness (number of species)
Evenness (how equal are the species in terms of abundance)
Example is with rank-abundance curve
How measure diversity?
Simpson's index (D), Shannon-Wiener index (H')
Simpson's index (D)
D=(sum)pi^2 measures the probability that any two individuals chosen randomly from the total population come from the same species
proportion of species in the community
less diversity more likely to ...... ...... ...... (and D gets ........)
to pick same species (D gets higher)
Often express as (1-D), which ranges from (0 to 1-1/s) (s= # species)
1/D is Simpson's reciprocal index (ranges from 1 to s)
Interpret as number of equally common species required to generate the observed heterogeneity of the sample
This formula biased for small sample sizes,and Simpson's index not sensitive to rare species
Shannon-Wiener index (H')
loge is just the natural logarithm of pi
e^H' Interpret as number of equally common species required to generate the observed heterogeneity of the sample
S-W index asks
-how difficult would it be to predict correctly the species of the next individual
Assumes random sample of large community
S-W index puts more weight on rare species
Food Webs summarize....
feeding relations in a community
This may be directly (predation, herbivory, parasitism) or after the food item is dead (detritivory)
Simple interactions are....
Food Chains but more realistic maps of interactions are Food Webs
This view of a community is based on
feeding, but there are other relationships between organisms that are not part of a food web
-habitat formation, competition, amensalism, commensalism are examples of non-food web interactions -pollination when no food is consumed is another
Food webs help identify
strong interactions and thus species that may have large influence in community -Indirect interactions are also important
One species affects another through a third intermediary species ex. beaver gets no benefits from beetle but beetle benefits from beaver
Occurs indirectly between two species which are differentially affected by the same natural enemy.
-For example, species A and species B are both prey of predator C. The increase of species A will cause the decrease of species B because the increase of As would increase the number of predator Cs which in turn will hunt more of species B
is a species that has a disproportionate effect on its environment relative to its abundance
-such species affect many other organisms in an ecosystem and help to determine the types and numbers of various others species in a community.
an ecosystem may experience a ........... if a keystone species is removed, even though that species was a small part of the ecosystem by measures of biomass or productivity
impact on keystone species may come through
competition, predation or herbivory, keystone species may be prey as well as predators, structure
some species may be able to exclude others, so that when the best competitor is removed, several species can invade
predation or herbivory
- removal of a predator or herbivore that feeds on the best competitor in a community may allow the that competitor to expand its population size so that it competitively excludes other species.
keystone species may be
prey as well as predators -loss of a keystone prey species results in loss of many predatory species
- some species may alter the environment in a way that creates opportunity of other species -trees become habitat for many animals -corals build reefs that become habitat for many algae and animals -Beavers are a classic keystone species that act as ecosystem engineers (elephants also example) -alter the environment by building their homes by making ponds -hundreds of species in the ponds rely on the presence of the beavers
Local patterns of species richness and diversity Species diversity tends to be .......
higher in complex environments
Intermediate levels of disturbance promote .........
higher diversity because allows some species to colonize but not enough time for competitive exclusion
Geographic patterns of species richness and diversity
*Equilibrium Model of Island Biogeography
Number of species on islands balance between regional processes that govern immigration and local processes that govern extinction.
P = pool of available species to colonize
S = equilibrium number of species that exist on island
Equilibrium Model of Island Biogeography
immigration would be highest on .........
rate decreases because ........
extinction rate increases because of ............ ....... ...
- new island with no organisms
-fewer arrivals would be new species
-competition, population size of each species likely decreases, and larger pool of species for potential extinctions
extinction on islands would be determined mainly by sland size
immigration determined by
by isolation from source of immigrants
Model not restricted to islands—
can happen on mainland in island like habitats (e.g., lakes
More species on..... ...... islands than ..... .......
-large and near, than small and far
Equilibrium model predicts species composition on islands is ..........
dynamic (number remains constant) -- change referred to as species turnover.
Species turnover occurring as a result of
equal levels of immigration and extinction
Species richness not always
Species richness generally (geographic)
increases from middle to higher latitudes to equator
Time Since Perturbation (Evolutionary hypothesis) -
More species in the tropics because tropics are older and disturbed less frequently so less extinction.
- Higher productivity supports higher species richness (data do not support this hypothesis very well).
-Studied for the clergy at Christ's College, Cambridge University.
-Interacted with some natural scientists (John Henslow and Adam Sedgwick) at Cambridge. - Offered a position (in 1831) as the ship's naturalist on the H.M.S. Beagle, which was going on an expedition to chart the waters of South America.
"that under these circumstances ..... variations would tend to be ..... and ....... ones to be ........"
the inferior would inevitably be killed off and the superior would remain - that is, the fittest would survive
WHAT ARE THE ELEMENTS OF EVOLUTION BY NATURAL SELECTION?
1)Individuals within populations are variable (phenotypic variation).
2)The variations among individuals are, at least in part, passed from parents to offspring (heritability - genetic component of phenotype).
3)In every generation, some individuals are more successful at surviving and reproduction than others (competition).
4)The survival and reproduction of individuals (fitness) are not random; instead they are linked to the phenotypic traits that vary among individuals.
Natural selection will result in the evolution of a trait if the ........ of that trait is ......... and results in ........ ..........
phenotypic variation, heritable and differential fitness.
the ability of an individual to survive and reproduce compared to other individuals (this is a relative statistic about individuals!!!).
a trait that increases the ability of an individual to survive and reproduce compared with individuals that differ in that trait (rephrased: a trait that has arisen via selection).
"survival of the fittest" is misleading because
-Survival only one component of fitness -Fit often synonymized with big, strong, or fast physical traits. Survival and reproduction (Fitness) may have nothing to do with such traits.
Testing the 4 postulates
1) Is there phenotypic variation in beak depth? 2) Is some of the variation among individuals heritable? 3) Do individuals vary in their survival or reproductive success? 4) Are survival and reproduction nonrandom with respect to the trait?
proportion of total phenotypic variation that is due to variation in genes
—multiple fathers for a nest -underestimate heritability
-unrelated offspring in nest -underestimate heritability
-similar conditions may result in similar phenotypes-overestimate heritability
-(eg nutrient stores in eggs)-overestimate if make you look like mom
traits (genes) are ........thus they have ...... ....... ........
independent, different evolutionary histories.
Do all traits evolve via natural selection?
Natural Selection acts on ......, but its consequences occur in .......
individuals, populations ex.Individual birds did not change, but their traits allowed some to better survive.
Evolution by any mechanism happens at the level of the .........
This is because evolution is a change in ...... ........
Natural Selection ..... .... ........., but evolution consists of changes in ........ .........
acts on Phenotypes, allele frequencies.
If variation in the phenotype is not heritable (i.e. there is no genetic basis for the phenotype), then ........
there will be no evolution.
The population level change observed in the offspring is a consequence of selection that ..... ...... ..........
happened in their parents.
e.g., - offspring of the finches that experience selection are better adapted to drought conditions.
If environment changes, these offspring may not achieve ....... ......
T/F : Organisms are NOT adapted to future conditions and selection does NOT look ahead or anticipate environmental changes.
T/F: Evolution is always a generation behind any changes in the environment.
New traits can evolve, even though ....... ....... ........ ..... .......
natural selection acts on existing traits:
There must be existing material (variation) for selection to act on, but: New traits can evolve because genetic material is NOT ......
static (e.g., mutation and recombination create new genetic material).
T/F Traits that originally evolved for one function may continue to evolve and acquire a new function (preadaptation or exaptation)
T/F Natural selection can simultaneously optimize all traits.
FALSE Natural selection <cannot> simultaneously optimize all traits.
T/F Selection can only operate on the available genetic variation.
T/F Changing one feature for the better might change another for the worse
Natural Selection is ........, but is not .........
Natural selection makes populations ........ only in the sense of increasing their ....... ........ to their environment
"better," average adaptation.
T/F: There is no inexorable trend toward more "advanced forms"
TRUE -e.g., tapeworms have no digestive system
Natural Selection acts on individuals, not for the good of ...... ......
the good of the species
T/F: If an allele that produced a completely altruistic behavior came into existence such that the behavior increased another's fitness relative to one's own fitness, the behavior would CONTINUE to produce in the population.
FALSE If an allele that produced a completely altruistic behavior came into existence such that the behavior increased another's fitness relative to one's own fitness, the behavior would soon DISAPPEAR from the population. (The allele would fail to be passed on).
Selection is ..... .. ....... in the sense that gravity is: Selection is not a guided or cognizant entity; it is simply an .......
not a force, an effect .
Two things missing from Darwin's theory He did not know how variation was.....
He did not know how variation was generated in populations—not until the early 1900's did we understand mutation
He did not know how variation was passed on to offspring—Gregor Mendel did in 1866 (but Darwin did not read his work)
- changes in allele frequencies (and thus, trait distributions) within populations.
We can often directly observe such changes in lab experiments or within our lifetime from natural experiments.
- Large evolutionary change, usually morphology, typically refers to differences among populations that would warrant species status.
Usually on a time scale beyond our lifetime, but speciation can happen over a single generation (polyploidy in plants). Uses a comparative and/or developmental approach with extant and/or extinct taxa.
- a rudimentary version of a body part that has an important function in other species
- show common ancestry via shared traits (a principle of phylogenetics)
The fossil record has examples of gradual change. The ..... of finding a transitional form is not evidence..... ...... ...... .......
lack, that it never existed.
A transitional form does not have to be a direct ........., it could be a ..... ...... that is now extinct ) -- ..... ...... will likely have some traits similar to its ancestor
ancestor, side branch, side branch
- any similarity between characteristics that is due to their shared ancestry - evidence of common ancestry
A scientist studying lake communities in Greece compares his data before and after water level reduction due to climate change to determine the effect of salinity and nutrient concentrations on the community of phytoplankton, zooplankton, and fish populations. This is an example of a:
A) Manipulative experiment B) Observational study C) Natural experiment D) Controlled experiment E) Laboratory study
C) Natural Experiment
Which of the following statements about scientific models is correct? A) A model is defined as observable and quantifiable evidence from the natural world. B) A model is the cause of the patterns observed in the natural world. C) A model is a formal scientific description of processes that produce patterns. D) Models are scientific laws, so they do not require additional testing. E) None of the above.
C) A model is a formal scientific description of processes that produce patterns.
Which of the following demonstrates the relevance of ecology and evolutionary biology to lives of humans?
A) Humans have genes. B) Human distributions and abundances can vary over time and space. C) Allele frequencies can change in human populations. D) All of the above. E) A and C.
D) All of the above.
If you were to eradicate malaria from a particular area, what factors should be considered?
A) The ecology of humans inhabiting the region. B) The surrounding environmental conditions such as temperature and water availability. C) The potential of mosquitoes to evolve resistance to pesticides. D) You can ignore A and B because they do not impact potential malarial control options. E) You should consider A, B, and C.
E) You should consider A, B, and C.
Which of the following statements about classes of biological molecules is NOT correct?
A) Proteins catalyze chemical reactions. B) DNA has the ability to carry information. C) RNA has the ability to carry information and catalyze chemical reactions. D) All of the above. E) None of the above.
E) None of the above.
Which of the following statement is NOT one of the necessary criteria for life as we know it?
A) The ability to store information specifying a phenotype. B) Energy acquisition and utilization for metabolism and growth. C) A silica based molecule to carry genetic information. D) The ability to produce progeny of the same type. E) All of the above are needed for life as we know it.
C) A silica based molecule to carry genetic information.
If the half-life of Uranium-235 is ~ 70 million years, and you measure a fossil sample as being composed of 12.5% Uranium-235 (87.5% lead-207), approximately how old is your sample?
A) 70 million years. B) 140 million years. C) 210 million years. D) 420 million years. E) 630 million years.
C) 210 million years.
Which of the following is FALSE?
A) A common feature of all extant life is that they all use DNA and proteins in a similar way. B) A whole genome approach supports Archaea and Eucarya as sister taxa with Bacteria. C) A gene that has undergone lateral gene transfer can make two taxa appear more closely related than they actually are. D) Reconstructing the evolutionary history of extant life using different set of genes produce the same phylogenetic relationships between taxa. E) All statements above are TRUE.
D) Reconstructing the evolutionary history of extant life using different set of genes produce the same phylogenetic relationships between taxa.
What does the existence of 2 billion years old fossil cyanobacteria indicates?
A) That cyanobacteria are the most recent common ancestors to all DNA based life. B) The earliest known evidence of life. C) That the most recent common ancestor of DNA based life existed at least 2 billion years ago. D) A and B. E) B and C.
C) That the most recent common ancestor of DNA based life existed at least 2 billion years ago.
Which type of organism would make a good compression fossil?
A) Slugs B) Rabbits C) Plants D) Clams E) All of the above.
Which of the following is FALSE?
A) The big 5 extinction events account for 96% of all extinctions. B) Within a taxonomic group, the background extinction rate is constant over time. C) The rate of extinction is likely to be higher in species with narrow geographic ranges than in species with broad geographic ranges. D) Mass extinctions are likely caused by rapid changes in climate followed by disruption of biotic interactions. E) All of the above are true.
A) The big 5 extinction events account for 96% of all extinctions.
Which factors cause global pattern in temperature and precipitation?
A) The incident solar radiation hitting the Earth's surface. B) The orientation of the earth's axis relative to the sun. C) The surface winds under the Coriolis effect. D) All of the above. E) A and C.
D) All of the above.
Which of the following statements about the climate diagram below is NOT correct?
DIAGRAM ON PAPER
A) The mean temperature does not substantially fluctuate throughout the year. B) The relative positions of the precipitation and temperature lines indicate water is available from October through April. C) The diagram is representative of the south hemisphere. D) The diagram is representative of a tropical rainforest. E) The diagram is representative of a tropical dry forest/savanna.
D) The diagram is representative of a tropical rainforest.
14. In a given ecosystem, if total plant production is 3% of total solar input and plant respiration accounts for 1.5%, which of the following statements are correct?
A) Gross primary production is 3%. B) Net primary production is 1.5%. C) 1.5% of energy is available to primary consumers. D) All of the above are correct. E) A and B.
D) All of the above are correct.
In this trophic cascade, what would cause a decrease in the primary production?
A) A decrease in nutrients availability. B) A reduction in the population of predators. C) A reduction in the population of forage fish. D) A and C. E) All of the above.
D) A and C.
What does contribute to the stability of a community?
A) The lack of disturbance. B) The capacity to resist the potential disturbance. C) The capacity to recover from the disturbance. D) All of the above. E) None of the above.
D) All of the above.
Which of the following characteristics does NOT affect Population Biology: A. Location of the area B. No. of individuals per unit area C. Age distributions D. None of the above
D. None of the above
An Ecological niche refers to habitat including its conditions and resources. A. True B. False
A. True, because it mentions conditions and resources.
Which of the following is true about distribution patterns? A. It is the temporal location of the organisms in a population B. Only biotic factors affect it C. All populations are uniformly distributed D. Both boundary and patterns within the boundary affect it
D. Both boundary and patterns within the boundary affect it
Population density increases with decreasing organism size. A. True B. False
Populations increases in size when: A. The birth rate exceeds the death rate B. Emigration exceeds immigration C. Mortality exceeds natality D. None of the above
A. The birth rate exceeds the death rate
A population in which most of the organisms die at later stages of its life span have a _____ survivorship curve. A. Type I B. Can not be defined C. Type II D. Type III
A. Type I
What does R0 = 2.4 mean? A. This population is decreasing B. This population is growing C. Each individual produces an average of 2.4 offspring during its lifetime D. Both B and C
D. Both B and C
Which of the following can be used to calculate the population size of populations with non-overlapping generations? A. Nt = N0(1+r)t B. Nt=N0λt C. Nt=N0R0t D. Both B and C
D. Both B and C
Which of the following are examples of trade-offs used by different organisms to maximize energy availability to perform different functions: A. Body size and no. of offspring B. Offspring number vs. offspring size C. Offspring size and dispersal D. All of the above
D. All of the above
Which of the following is an example of interactions where at least one of the species is negatively affected? A. Neutralism B. Commensalism C. Mutualism D. Competition
lx = nx / n0
R0= Σ lxmx
T= (sum of x times lx times mx) / R0
r = (ln R0) / T
Nt formula-geometric growth
Nt = N0λt
Nt -exponential growth
Nt = N0 (e)rt
D= sum of pi^2
know H' formula
H'= sum of (pilnpi)
N1 = eH'
Which of the following factors is NOT one that we use to characterize population? a) abundance b) species diversity c) rates of growth d) immigration and emigration e) B & C
b) species diversity
Area is filled with predators that hunt the butterfly that feed on the milkweed. What would the actual area that the butterflies feed be called? Realized or Fundamental? full range of environmental conditions under which the organism can exist OR area consists of conditions under which the organism actually survives, grows, and reproduces.
Realized niche, because the area consists of conditions under which the organism actually survives.
NOT true about survivorship curves? A type 1 b) type III c) bullfrogs d) b&c are false e) all of the above.
b) type III
Represent abiotic factors that determine growth in the natural productionl
D. Weather conditions
NOT assumptions of logistic population growth?
C. Population grows slowly early on
Humans are what type?
K is eroporous or semelparous?
3 distribution patterns commonly found in populations
regular (uniform), random, and clumped (aggregated)
what type of distribution pattern do humans fall under?
Equilibrium is when there is
no net change in the system
the smaller the organisms the higher the ......
semelparous variable and example
r and elephants
iteroparous variable and example
k and rabbit
geometric growth is for (overlapping/nonoverlapping) organisms.
nonoverlapping (remember acronym noyt)
exponential growth is for (overlapping/nonoverlapping) organisms.
overlapping (remember acronym noert or nert)
Assumptions of logistic population growth (3)
no migration, constant K, and all individuals are equal.
age-distribution pyramids and implications- how to recognize
young:old above 50:50 ratio is growing population at 50:50 ratio is equilibrium between 50:50 and 25:75 ratio is aging population below 25:75 is an aged population
pros of sexual and asexual reproduction
sexual: genetic diversity asexual: no mate, phenotype is already successful
cons of sexual and asexual reproduction
sexual: need a mate, pass on only 50% of genetic material. asexual: less genetic diversity, all offspring vulnerable to same things.
Correlation between body size, offspring size, offspring number, and gene flow?
high body size, high offspring size, few offspring number, lower gene flow (because of fewer offspring). vs versa---> low body size, low offspring size, high offspring number, higher gene flow (because of more offspring).
Why do we not look at organisms in terms of "higher an lower"?
No, because natural selection only makes them more adapted to the environment.