Ecology

Marked animals in second sample / Total caught in second sample = Marked animals in first sample / Total population size

5 / 20 = 16 / N ...... N=64

Huffaker 1958

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Janzen 1969

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Model

Verbal or Mathematical statement of a hypothesis.

Zebra Mussel (Dreissena polymorpha)

Very efficient filter feeders, had positive impact on water quality.

Numerical Response

The change in the numbers or density of a predator in relation to changes in the density of its prey species.

Chthamalus stellatus

"Southern" species that is absent from the colder waters of the British east cost. More north the barnacle is found it becomes restricted to higher and higher intertidal zones. Tolerant of long periods of exposure to air. Upperrange determined by desiccation and lower limit determined by competition for space.

Two Sampling Methods

"Use of quadrats" and the "Capture-recapture method".

Relative Density

(that is, for two areas of equal size, area x has more organisms than area y). This division of approaches is reflected in the techniques developed for measuring density.

Three ecological explanations for Rapoprt's Rule

1) Climatic variability is greater at high latitudes, and only organisms that have a broad range of tolerance for variable climates can live there. 2) A product of glaciation, when glaciers retreated only those spcies with high dispersal capacity were able to repopulate northern areas, and these species thus have large geographic ranges. 3) Lack of competition in polar communities. Because fewer species live in polar area, the level of competition may be lower.

Assumptions of Capture-recapture models

1) Marked and unmarked animals are captured randomly 2) Marked animals are subject to the same mortality rate as unmarked animals. The Petersen method assumes there is no mortality during the sampling interval. 3) Marked animals are neither lost nor overlooked.

Three explanations of why distribution and abundance may be correlated.

1) Sampling Model, which argues that the observed relationship is an artifact of sampling and does not require a biological explanation. 2) Ecological specialization model, argues that species that can exploit a wide range of resources become both widespread and common. These species are called generalists and are to be distinguished from specialists, which exploit only a few resources. 3) Local Population Model, A Population is subdivided into a series of discrete patches, or local populations, that interact because animals or plants move between the patches.

Plants of the same species growing in diverse environments

1) all differences are phenotypic, and seeds transplanted from one situation to the other will respond exactly as the resident individuals. 2) all differences are genotypic, and if seeds are transplanted between areas, the mature plants will retain the form and physiology typical for their original habitat. 3) Some combination of phenotypic and genotypic determination produces an intermediate result most common in natural selection.

Species can adopt general evolutionary strategies.

1. Avoid the superior competitor by selecting a different part of the habitat. 2. Avoid the superior competitor by making a change in diet.

Four criteria predator restriction

1. Prey individuals will survive when Transplanted to a site where they do not normally occur if they are protected from predators. 2. The distributions of prey organisms and suspected predator(s) are inversely correlated. 3. The suspected predator is able to kill the prey, both in the field and in the laboratory. 4. The suspected predator can be shown to be responsible for the destruction of the prey in transplantation experiments.

Natural Selection needs

1. They have the ability to replicate, 2. they produce an excess number of units above replacement needs, 3. survival depends on some attribute (size, color, behavior) , 4. a mechanism exists for the transmission of these attribute.

Natural Selection: Operational Steps:

1. Variation occurs in every group. Individuals of the same species are not identical in any population. 2.Every population of organism produces an excess of offspring. 3. Life is difficult, and not all individuals will survive and reproduce. 4. Individuals best able to obtain and use these resources will survive and reproduce. 5. if the characteristics of these organisms are inherited, the favored traits will be more frequent in the next generation.

Drought Resistance is achieved by

1. improvement of water uptake by roots, 2. reduction of water loss by stomatal closure, prevention of cuticular respiration, and reduction leaf surface, 3. storage of water. Leaqves of plants subject to poor water supply often have smaller surface areas and thicker cuticles, both of which reduce evaporation losses.

Optimal Foraging Theory

A detailed model of how animals should forage to maximize their fitness.

Matrix Models

A family of models of population change based on matrix algebra, with the Leslie matrix model being the best known.

Crassulacean Acid Metabolism (CAM)

A form of photosynthesis in which the two chemical parts of photosynthesis are separated in time because CO2 is taken up at night through the stomata (which are then closed during the day) and fixed to be used later in the day to complete photosynthesis carbon fixation; an adaptation used by desert plants to conserve water.

Ecotype

A genetic race of a plant or animal species that is adapted to a specific set of environmental conditions such as temperature or salinity. Describing genetic varieties within a single species.

Leslie matrix model

A method of casting the age-specific reproductive schedule and the age-specific mortality schedule of a population in matrix form so that predictions of future population change can be made.

Mycorrhizae

A mutually beneficial association of a fungus and the roots of a plant in which the plant's mineral absorption is enhanced and the fungus obtains nutrients from the plant.

Disease

A pathological condition of an organism resulting from various causes, such as an infection, a genetic disorder, or environmental stress, with specific symptoms.

Deme

A population genetic unit of individuals that breed with one another; a genetic population. Which are groups of interbreeding organisms, the smallest collective unit of a plant or animal population. Individuals in local populations share a common gene pool.

Ecological Specialization Model

A proposed explanation for Hanski's Rule postulationg that species that exploit a wide range of resources become both widespread and common; these species are generalists; also called Brown's model. a corollary of this model is that widespread generalist species should use food and habitat resources that are themselves abundant.

Local Population Model

A proposed explanation for Hanski's Rule that assumes that species differ in their capacity to disperse, and if the environment is divided into patches, some species will occupy more local patches than others as a function of their dispersal powers.

Mutualism

A relation between two organisms of different species that benefits both and harms neither.

Ideal Free Distribution

A theoretical spatial spread of members of a population in which individuals take up areas with equal amounts of resources in relation to their needs, so all individuals do equally well (the polar opposite to the ideal despotic distribution).

Ideal Despotic Distribution

A theoretical spatial spread of members of a population in which the competitive dominant "aggressive individuals take up the best resources and territories, and less competitive individuals take up areas or resources in direct relationship to their dominance status. Most importantly, the ideal distribution predicts that fitness will be lower in the poorer habitats.

Resource Availability Hypothesis

A theory of plant defense that predicts higher plant growth rates will result in less investment in defensive chemicals and structures. Example, rain forest trees in panama, Strong negative correlation between growth rate and defense levels. Key idea, growth rates in plants are strongly affected by the available resources.

Type 3

Curves indicate high per capita mortality early in life, followed by a period of much lower and relatively constant loss. This type occurs in many fishes, marine invertebrates, and parasites.

Use of Quadrats 2

Achieving reliable estimates using this technique requires three things: 1) The population of each quadrat examined must be determined accurately. 2) the area of each quadrat must be known, and 3) the quadrats counted must be representative of the whole area example- random sampling.

r-selected species

Adapted to life in the exponential growth phase. Geometric Growth. Unstable habitat/resources. Short life, early reproduction. Less investment in defenses for interspecific competition.

Static Life table

Also called a stationary, time specific, current, or vertical life table. is calculated on the basis of a cross section of a population at a specific time.

Historical Constraints (Adaptation)

Always present because organisms have a history and change in small increments.

Common Garden

An experimental design in plant ecophysoppgy in which a series of plants from different areas are brought together and planted in one area, side by side, in an attempt to determine which features of the plants are genetically controlled and which are environmentally determined. Made by Gote Turesson. Example, two subspecies of Plantago maritima, grown side by side have different heights, Marsh population 31.5cm and Cliff population 20.7cm. Is an attempt to separate the phenotypic (environmental) and genotypic (genetic) components of variation. (Mesocosm Experiment)

Theory

An integrated and hierarchical set of empirical hypotheses that together explain a significant fraction of scientific observations. The theory of evolution is perhaps the most frequently used theory in ecology.

Habitat

Any part of the biosphere where a particular species can live, either temporarily or permanently.

Birch 1948

Applied human growth rate techniques to ecology. Earlier age of 1st reproduction and shorter generation times increases r.

Apparent Plants

Are those found easily by herbivores.

Cowbirds

Arms Race, Nest Parasitism

Natural Selection acts on Phenotypes,

Different genotypes give rise to different phenotypes, but often not a direct translation due to temperature and other environmental factors.

Ideal Free Distribution 2

As a population fills up the best habitat, it reaches a point where the suitability of the intermediate habitat is equal to that in habitat A, so individuals will now enter both habitats A and B. As these two habitats fill even more, the poor habitat finally has a suitability equal to that of habitats A and B.

Ideal Despotic Distribution

Assumes the dominate species get the best habitats. Example Spotted owl population. Opposes the Ideal free distribution model.

Disruptive Selection

Both extremes are favored over the mean. Example the black belly nutcracker. Bimodal graph created. Isolating mechanisms are an important adjunct of disruptive selection. Important for speciation.

Methods for measuring relative density: Number of fecal pellets

Been used for snowshoe hares, deer, field mice, and rabbits. if we know the average rate of defecation, the number of fecal pellets in an area can provide an index of population size. Similar methods are used for defoliating caterpillars by estimating the amount of frass falling from trees.

Cane Toad (Bufo Marinus)

Believed to control scarab beetles, an insect pest of sugarcane. Failed to control the pest and became a pest itself.

Intraspecific

Between members of the same species.

Interspecific

Between two or more different species.

Crossbills

Bill adaptation can be interpreted as devices for minimizing dietary overlap in regions where all three possible competitors live. Disruptive selection maintained four types of red crossbills in western north America because bill size had great efficiency for size of crossbill beak.

Tolerances of species

Can change via the process of natural selection. Example, plants that have adaptations to heavy-metal toxicity and serpentine soils.

Group Selection

Can occur when populations of a species are broken up into discrete groups more or less isolated from other such groups. Thus, groups that contain less adaptive genes can become extinct. Considered to be rare in nature. Operates at cross purposes with individual selection

Population Parameters

Change Density- 1) Natality (egg, seed, or spore production; births), 2) Mortality (deaths), 3) Immigration, and 4) Emigration. Secondary characteristics of a population are age distribution, genetic composition, and pattern of distribution of individuals in space.

Oak Leafs

Change in color and become tougher as the season progresses. Increased tannin as a chemical defense and altered leaf texture (toughness) as a structural defense. Herbivores have compensated by concentrating feeding in the early spring on young leaves and by altering life cycles in the summer and fall.

Secondary Plant Substances

Chemicals produced by plants that are not directly involved in the primary metabolic pathways and whose main function is to repel herbivores. Costly to make.

Individual Optimization Hypothesis

Clutch size is under strong genetic control in birds. one female may consistently lay three eggs and this may be best for her, while another female in the same population may consistently lay five eggs and this maybe best for her. Explains the considerable variation in clutch size within a population.

Western Hemlock

Coastal populations - have no or little overlap of AET (Actual Evapotranspiration) meaning it has colonized most all areas it can. Interior Populations - have AET overlap suggesting that they have not yet colonized all sites that are suitable climatically

Yarrow- achillea

Common Garden Experiment example.

Six Interactions between individuals.

Competition, Predation, Herbivory, Parasitism, Disease, and Mutualism.

Gause's Hypothesis

Complete competitors cannot coexist, also called the competitive exclusion principle.

Use of quadrats

Count all the individuals in several areas of known size and then to extrapolate the average count to the whole area. Sampling area of any shape. Example, if you counted 19, 21, 17, and 19 individuals of a beetle species in four soil samples of 10 cm by 10 cm, you could extrapolate this to 1900 beetles per square meter of soil surface.

Type 1

Curves are characteristic of populations with low per capita mortality for most of the life span and then high losses of older organisms. Developed nations have this type.

Three ways in which species spread geographically

Diffusion, Jump Dispersal, and Secular Dispersal.

Ecology three points of view:

Descriptive, Functional, or Evolutionary.

Age at Death Observed

Data used to estimate the life-table functions for a static life table.

Unitary Organisms

Deer, mice, humans, and oak trees identify as individuals. Higher animals, form is determinate or defined limits. Usually a separate genetic individual.

Plant Fitness Predictions 4

Defense mechanisms are costly and cannot be maintained if plants are severely stressed by environmental factors.

Plant Fitness Predictions 3

Defense mechanisms are reduced when enemies are absent, and increased when plants are attacked.

The number of new infections among people

Depends on the number and infectivity of mosquitoes.

Three types of selection can operate on phenotypic characters:

Directional, Stabilizing, and Disruptive Selection.

Transplant unsuccessful

Distribution is limited either by other species or by physical or chemical factors

Transplant Successful

Distribution limited either because the area is inaccessible, time has been to short to reach the area, or because the species fails to recognize the area is suitable living space. Indicates that the potential range of the species is larger than its actual range.

Distance Moved =

Dn SquareRoot (Log_e_ R0)

Modular Organisms

Do not come in simple units of individuals. Most plants. For example grasses, difficult to fit into anyone's definition of a single individual, and many other plants have underground connections so that what appear to be separate plants are the same genetic individual (a clone). aka Aspen trees. When existing separately are known as "ramets". Lower animals. Can have individuals that are extremely different in size.

Range Reduction

Due to introduced predators the prey has it's distribution restricted. Also, can operate in the other direction, and the prey may restrict the distribution of its predator (only specialized predators) .

Functional: Ecology point of view:

Dynamics and relationships, seeks to identify and analyze general problems common to most or all of the different ecosystems. Deals with populations and communities as they exist and can be measured now. (Proximate Causes)

Realized Fertility

Ecological concept that is based on the number of viable offspring produced during a period of time.

Age Structure Directly Observed

Ecological information , particularly of trees, birds, and fishes, is considerable and in some cases can be used to construct a static life table.

Ecology

Ecology is the scientific study of the interactions that determine the distribution and abundance of organisms.

Rain Deficit & Extremely Arid

Evaporation exceeds precipitation, Evaporation at least twice as great as precipitation.

Adaptation

Evolution through natural selection results in adaptation, and under appropriate conditions produces new species (Speciation). Has important ecological implications because it sets limits to the life cycle traits that determine distribution and abundance.

Rough-skinned newts & Common Gater Snakes

Evolutionary "Arms Races"

Intrinsic Capacity for Increase Depends on

Fertility, Longevity, and Speed of Development.

Natality rate and Death rate

Fertility, longevity, and speed of development is interceded and measured by theses rates.

Sugarcane

Fixes CO2 by first producing malic and aspartic acids (four carbon acids), and is called the C4 pathway of photosynthesis. C4 plants have all the biochemical elements of the C3 pathway, so they can use either method to fix CO2. C4 plants do not reach saturation light levels even under the brightest sunlight, and they always produce more photosynthate per unit area of leaf than C3 plants.

Longevity

Focus on the age of death of individuals in a population.

Safe Sites

For animals, sites where prey individuals are able to avoid predation; for plants, sites where seeds can germinate and plants can grow.

Adaptation Four Major Forces

Genetic forces, environments are continually changing, adaptation is a compromise, and historical constraints.

Four biological disciplines related to ecology.

Genetics, Evolution, Physiology, and Behavior.

Deterministic Models

Given certain initial conditions, each model predicts one exact outcome.

Three-spine sticklebacks (Gasterosteus aculeatus)

Good example of disruptive selection. Two forms of sticklebacks exist (Large, Small). Small form lives in open water and feeds on small plankton. Large form feeds on bottom of lakes and feeds on insects and crustaceans. Came from two separate sea level invasions.

Acclimation

Gradual, Reversible, Often temporary change in an individual to adjust to environment.

Population

Group of organisms of the same species occupying a particular space at a particular time.

Plantago Maritima

Grows both as a tall, robust plant in marshes along the coast of Sweden and as a dwarf plant on exposed sea cliffs in the Faeroe islands.

Semibalanus balanoides

Grows faster than other barnacles in the middle part of the intertidal zone and out competes most. Upper limit set by weather factors, sensitivity of young barnacles. The lower limit set by competition of space with algae and by predation by Thais lapillus.

Unapparent Plants

Hard for herbivores to find because they are small or rare or short lived.

Polar areas

Have low precipitation but are not arid because the amount of evaporation is also low.

Proximate Factors

How a particular trait is regulated by an individual in a physiological or biochemical manner. Example, _____ factors that determine clutch size are the physiological factors that control ovulation and egg laying. Right Now.

Functional

How do species and environment interact? What are the proximate Mechanisms? Example earth worms rise to surface because they cannot breathe.

Abundance

How many organisms are found in a given area.

California Sea Otter (Enhydra lutris)

Hunted to very low numbers by 1900. now considered a potential "pest" in some marine reserves. Mink abundance & distribution decreased after otter release due to competition. aka INFLUENCE of COMPETITION

Secular Dispersal

If diffusion occurs in evolutionary time, the species that is spreading undergoes extensive evolutionary change in the process. The geographic range of a secularly dispersing species expands over geologic time, but at the same time natural selection is causing the migrants to diverge from the ancestral population. An important process in biogeography, but, since it occurs in evolutionary time, it is rarely of immediate interest for ecologists working in ecological time.

Founder Effect

If the dispersing individuals are not a random sample of the population, dispersal of the new population may be genetically quite distinct from the source population.

Capture-recapture method

Important for mobile animals, it allows for density estimates, birth rate estimates, and death rate estimates. The proportion of animals marked in subsequent samples taken from this population should be representative of the proportion marked in the entire population.

Control

In an experimental design a control is a treatment or plot in which nothing is changed so that it serves as a baseline for comparison with the experimental treatments to which something is typically added or subtracted.

Probabilistic Models

In contrast to deterministic models, including an element of probability so that repeated runs of the models do not produce exactly the same outcome.

Physiological

Individual level, BIOTIC

Spines and thorns in Terrestrial Plants

Induced defenses are reduced or lost in the absence of herbivore damage. Example, intensively grazed cactus produce more spines, ungrazed cactus have way less spines. More spines costs a cactus and so produces less fruit than cactus with less spines.

Connell 1961

Influence of Interspecific Competition and other factors on the distribution of the barnacle Chthamalus Stellatus. Top was limited by Abiotic factors (tempature) and the bottom was limited by biotic factors (Compition) (Predation)

RuDP carboxylase enzyme

Inhibited by oxygen in the air and has lower affinity for CO2

Contest Competition

Interference Competition, Occurs when the organisms seeking a resource harm one another in the process, even if the resources that are in short supply. Has "Winners" and "Losers"

Peterson Method

Involves only two sampling periods: capture, mark, and release at time 1 and capture and check for marked animals at time 2.

Diffusion

Is the gradual movement of a population across hospitable terrain for a period of several generations. This common form of dispersal is illustrated by the sea otter in California and the cane toad in Australia.

Jump dispersal

Jump dispersal is the movement of individual organisms across large distances followed by the successful establishment of a population in the new area. This form of dispersal occurs in a short time during the life of an individual, and the movement usually occurs across unsuitable terrain. Island colonization is achieved by jump dispersal, and human introductions such as the African honey bee can be viewed as an assisted form of jump dispersal.

What sets the limit of Treelines or Timberlines?

Lack of soil, Desiccation of leaves in cold weather, short growing season, lack of snow exposing plants to winter drying, excessive snow lasting through the summer, mechanical effects of high winds, rapid heat loss at night, excessive soil temperatures during the day, and drought.

Determinate Layers

Lay a given number of eggs, no matter what. Example, Pigeons lays two eggs; if you take away the first, it will incubate the second egg only. If you add a third egg, it will incubate all three.

Indeterminate Layers

Lay eggs until the nest is "full". if eggs are removed once they are laid, these birds will continue laying. Evidence suggests that most birds under normal circumstances do not lay their physiological limit of eggs but that ovulation is stopped long before this limit is reached.

Range Extension study

Learn more about how organisms can extend their tolerance limits.

Krantz Anatomy

Leaves where the chloroplast are concentrated in two-layered bundles around the veins of the leaf. For C4 plants. The bundle sheath cells in C4 plants also have a high concentration of mitochondria. The C4 leaf anatomy is more efficient for utilizing low CO2 concentrations, for recycling the CO2 produced in respiration, and for rapidly translocating starches to other parts of the leaf.

Tradeoff

Loons very good at diving but not so good at flying.

Natality

Major factor in population increase, broad term covering the production of new individuals by birth, hatching, germination, or fission.

Lack Clutch Size

Maximum clutch size.

Optimality Models

Models that assume natural selection will achieve adaptations that are the best possible for each trait in terms of survival and reproduction.

Community Ecoligst

More than 1 species, more than 1 biotic factor

Changing Environments (Adaptation)

Most significant short-term constraint on adaptation.

Ecosytem

Multiple species with both biotic and abiotic factors.

Theory of Maximum Reproduction

Natural selection would seem to operate to maximize reproductive rate, subject to the constraints imposed by feeding and predator avoidance. Good example of how stabilizing selection can operate on a phenotypic trait such as reproductive rate.

Limits imposed by other species may involve

Negative effects of predators, parasites, disease organisms, or competitors, or the positive effects of interdependent species within the actual range.

Competition

Negative interaction between two species over resources. Allelopathy is one specific type of competition for living space. Two species do not need to be closely related to be involved in competition.

Grinnell 1917

Niche-Relationships of the California Thrasher. DESCRIPTIVE ecology. examples, natural history, distributions, descriptions.

Sampling Model

One proposed explanation for Hanski's Rule that the observed relationship between distribution and abundance is an artifact of the difficulty of sampling rare species and does not therefore require a biological explanation.

Per capita death rate (qx) =

No. of deaths (dx) / population at risk (nx)

Fitness in Not:

Not Absolute, specific for a given environment. cannot be compared across species, defined only within a single species. Not only about reproduction, high reproductive rates may not by themselves confer high fitness if survival rates of these young are poor. Not a short-term measure, should be measured across several generations. Not about individual traits, evolutions is a whole-organism affair. but the test of fitness is the test of whole-organism survival and reproduction.

Davidson & Andrewartha 1948

Not always competition (biotic factors) limits ranges but rather abiotic factors play a key role. Worked on measuring the association between the density of thrips population and the weather.

PEP carboxylase enzyme

Not inhibited by oxygen and has a higher affinity for CO2. With this biochemical information we can predict that C4 plants would be at an advantage when photosynthesis is limited by CO2 concentration. This occurs under high light intensities and high temperatures and when water is in short supply. C4 grasses, sedges, and dicotyledons are all more common in tropical areas than in temperate or polar areas.

nx

Number alive at age x

Competition 1

Occurs when the number of organisms of the same or different species utilize common resources that are in short supply or when the organisms harm one another in the process of acquiring these resources.

Big-Bang Reproduction

Offspring are produced in one burst rather than in a repeated manner.

Young Animal Stages

Often are most sensitive to environmental factors. These tolerance limits define the fundamental niche of the species.

Methods for measuring relative density: Traps

Often used in capture-recapture studies to estimate absolute density. The number of individuals caught per day per trap may also be used as an index of relative density.

Mussel Distribution (Mytilus edulis)

On the open coast, heavy wave action restricts the size of mussels and prevents predators from eliminating small mussels. In sheltered waters, predators eliminate most of the small mussels, and Mytilus survive only in refuge area safe from predators (such as steep rock faces), where they may grow to large sizes.

Allelopathy

Organisms that alter the surrounding chemical environment in such a way as to prevent other species from using it, typically with toxins or antibiotics. Example, penicillin among microorganisms is a classical case.

Demography

Originated as the study of human population growth and decline. It is now used as a more general term that includes plant and animal population changes.

Tolerance studies can be used for:

Oxygen, pH, and salinity thus building up a detailed picture of the tolerance limits of any particular species of plant or animal.

Stabilizing Selection

Phenotypes near the mean of the population are fitter than those at either extreme; thus, the population mean value does not change. Very common in present-day populations. Example is birth weight in humans in the United States. Mean is tighter stays the same.

Potential Fecundity

Physiological notion that refers to an organism's potential reproductive capacity. Usually inversely related to the amount of parental care given to the young.

Inducible Defenses

Plant defense methods that are called into action once herbivore attack occurs and are nearly absent during periods of no herbivory. NOT structural defenses.

Plant Fitness Prediction 2

Plants allocate more defenses to valuable tissues that are at risk. Example, Gastropod grazing of the critical basal shoots increased tannin content by 55%.

Plant Fitness Prediction 1

Plants evolve more defenses if they are exposed to much damage, and fewer defenses if the cost of defense is high.

Shade-tolerant plants

Plants that can live and grow in the shade of other plants. Have lower photosynthetic rates and hence would be expected to have lower growth rates. Metabolic rate of seedlings is lower. Adapting to shade involves becoming resistant to fungal infections. Tradeoff include

Shade-intolerant plants

Plants that cannot survive and grow in the shade of another plant, requiring open habitats for survival. Plants species become adapted to live in a certain kind of habitat and in the process evolve a series of characteristics "adaptive syndrome" that prevent them from occupying other habitats.

Light as a Limiting Factor

Plants use it as a cue for the timing of daily and seasonal rhythms in both animals and plants, and photosynthesis. example, nocturnal desert animals use light as a cue for their activity cycles.

Natality Rate exceeds death rate

Populations will increase.

Total Counts

Possible for very few organisms.

Generalist Predators

Predators that eat a great variety of prey species.

Genetic Forces (Adaptation)

Prevent perfect adaptation because of mutation and gene flow. Mutation is always occurring, generation variation in populations and mot mutations are detrimental to organisms rather than adaptive. Alleles.

lx

Proportion of organisms surviving from the start of the life table to age x

Descriptive Statistics

Provide an overview of the attributes of a data set; include measurements of central tendency (histograms, mean, median, & mode) & dispersion (Range, Variance& standard deviation)

Inferential Statistics

Provide measures of how well data support a hypothesis & if data are generalizable beyond what was tested (significance tests)

What determines clutch size?

Proximate factors-hormones temperatures day length. Ultimate Factors, Food availability.

America Birds

Range size is affected both by temperature and by topography. Birds in mountains areas had limited ranges, compared to birds in open areas.

Adaptive Divergence can be shown by

Reciprocal transplant experiments. The existence of genetic variants or strains within a single species illustrates that local adaptation occurs, and these local differences can be a precursor to speciation or its reverse.

Study populations of modular organisms

Recognize two levels of population structure. In addition to the number of modular units, there is the number of individuals that are represented by original zygotes. These individuals are called genets or genetic individuals. Example, Single tree or a clone extending over a square kilometer. Grasses grow above ground as tillers (= ramets), the modular unit of construction. Thus to describe a population of modular organisms, we must specify both the number of genets and the number of modular ramets. Possibly used biomass (weight) instead of counting numbers.

Scramble or Exploitative Competition

Resource Competition- Occurs when a number of organisms (of the same or of different species) utilize common resources that are in short supply. No "winners" or "Losers"

Net Reproductive Rate

Ro

Methods for measuring relative density: Questionnaires

Sent to sportsmen or trappers to get a subjective estimate of population changes. This technique is useful only for detecting large changes in population among animals large changes in population among animals large enough to be noticed.

Trade-off Shade & Drought

Shade tolerance is negatively related to drought tolerance and water logging tolerance. Oaks vs. Pines, both groups there is a strong trade-off: a species can be shade tolerant or drought tolerant but not both. Because of three photosynthetic strategies: C3 pathway, C4 pathway, and crassulacean acid metabolism.

Age Interval

Shorter increases the detail of mortality picture but requires more data.

Rock wallaby and Red Foxes

Small kangaroos have been driven to near extinction from predation. A test that poisoned red foxes help recover kangaroo populations. Foxes also reduced safe feeding areas to around rocky escape habitat. Predator is believed to restrict the distribution of its prey.

Agrostis tenuis (Grass)

Some populations are copper-tolerant evolved by rapid natural selection. Current populations are maintained by strong disruptive selection. There is a cost to being tolerant to heavy-metal pollutions. They grow poorly in normal soils because they require high amounts of heavy medal to survive. Tolerant plants are at a selective disadvantage away from contaminated soils.

Hanksi's Rule

Species have highest abundance near center of range. The positive relationship between distribution and abundance. Example, More widespread moth species tend to be more abundant. Similar patterns can be found in birds.

Generalists

Species that eat a variety of foods or live in a variety of habitats; contrast with specialists.

Specialists

Species that eat only a few foods or live in only one or two habitats; contrast with generalists.

Rapoport's Rule 2

States that polar species have larger geographic ranges than tropical species. Climatic variability, glaciation history, and competition are cited as the main causes of this pattern.

3 Types of data to construct life tables.

Survivorship Directly Observed, Age at death observed, and Age structure directly observed.

Experiment

Test of a hypothesis. It can be observational (observe the system) or manipulative (perturb the system). The experimental method is the scientific method.

Pearl 1927

Testing the logistic growth theory. By growing yeast. Ushered in the area of Logistic growth. S-Shaped.

Lack's Hypothesis

That clutch size in birds is determined by the number of young that parents can provide with food.

Individual Optimization Hypothesis

That each individual in a population has its own optimal clutch size, so that not all individuals are identical.

Production Ecology

The Study of the Harvestable yields of plants and animals. "Optimum-yield problem"

Fitness

The ability of a particular genotype or phenotype to leave descendants in future generations, relative to other organisms.

Predation

The action of one organism killing and eating another.

Actual Evapotranspiration

The actual amount of water that is used by and evaporates from a plant community over a given time period, largely dependent on the available water and the temperature.

Realized Longevity

The actual life span of an organism. Can be averaged for all the individuals in a population living under real environmental conditions, and this average longevity can be measured in the field, whereas potential longevity can be measured only in the laboratory or in a zoo or botanical garden.

Life Table

The age-specific mortality schedule of a population. Operating on a cohort of individuals, a cohort may include the entire population, or it may include only males, or only individuals born in a given year. If you are given any one of the columns of the life table, you can calculate the rest. two types Cohort and static.

Ants and Acacias

The ants depend on the acacia tree for food and a place to live, and the acacia depends on the ants for protection from herbivores and neighboring plants. A model system of the coevolution of two species in an association of mutual benefit.

Mean Length of a Generation

The average length of time between the birth of a female and her offspring.

Reproductive Rate (R0)

The average number of offspring produced per female or reproductive unit.

Habitat Selection

The behavioral actions of organisms (typically animals) in choosing the areas in which they live and breed.

Functional Response

The change in the intake rate of a predator in relation to the density of its prey species.

Lack Clutch Size

The clutch size at which productivity is maximal for the population.

Prey Isocline

The contour line of densities of predator and prey at which the prey are in equilibrium; the impact of a predator exactly balances the prey's rate of population growth, so the prey population growth rate is zero.

Reproductive Value

The contribution an individual female will make to the future population.

Semibalanus balanoides & Chthamalus stellatus

The distribution of these barnacles is a striking example of limitations imposed by both physical factors, abiotic factors (temperature, desiccation) at the upper intertidal limits and biotic factors (competition, predation) at lower limits.

Character Displacement

The divergence in morphology between similar species in the region where the species both occur, but this divergence is reduced or lost in regions where the species distributions do not overlap, presumed to be caused by competition.

Proximate Causes: (Functional)

The dynamic responses of population and communities to immediate factors of the environment. How does a system operate?

Herbivory

The eating of parts of plants by animals, not typically resulting in plant death.

Shelford's Law of Tolerance

The ecological rule first described by Victor Shelford that "the geographical distribution of a species will be controlled by that environmental factor for which the organism has the narrowest range of tolerance".

Fundamental Niche

The ecological space occupied by a species in the absence of competition and other biotic interactions from other species. an n-dimensional hypervolume describing the resources that a species can utilize in the absence of competition. Rarely found in nature.

Niche

The ecological space occupied by a species, and the occupation of the species in a community.

Coevolution

The evolution of two or more species that interact closely with one another, with each species adapting to changes in the other.

Ultimate Factors

The evolutionary reason for an adaptation or why a trait is maintained in a population; opposite of proximate factors. Are selective factors. Over Time.

Ultimate Causes: (Evolutionary)

The historical reasons why natural selection has favored the particular adaptations we now see. Why does natural selection favor the particular ecological solution?

Population Regulation

The general problem of what prevents populations from growing without limit, and what determines the average abundance of a species.

Liebig's Law of the Minimum

The generalization first stated by Justus von Liebig that the rate of any biological process is limited by that factor in least amount relative to requirements, so there is a single limiting factor.

Rapoport's Rule

The generalization that geographic range sizes decrease as one moves from polar to equatorial latitudes, such that range sizes are smaller in the tropics.

Hanski's Rule

The generalization that there is a positive relationship between distribution and abundance, such that abundant species have wide geographic ranges.

Sheepshead Minnow

The highest critical maximum temperature of any fish yet tested.

Overcompensation Hypothesis

The idea that a small amount of grazing will increase plant growth and fitness rather than cause harm to the plant.

Plant Vigor Hypothesis

The idea that herbivores prefer to attack fast-growing, vigorous plants rather than slow growing, stressed plants.

Plant Stress Hypothesis

The idea that herbivores prefer to attack stressed plants, which produce leaves that are higher in nitrogen.

Optimal Defense Hypothesis

The idea that plants allocate defenses against herbivores in a manner that maximizes individual plant fitness, and that defenses are costly to produce.

Survivorship Directly Observed

The information on survival (lx) of a large cohort born at the same time, followed at close intervals throughout its existence, is best to have, since it generates a cohort life table directly and does not involve the assumption that the population is stable over time.

Treeline or Timberline

The limit of trees as a vegetation type. Nine factors influence timberlines. 1) Lack of soil 2) Desiccation of leaves in cold weather 3) Short growing season 4) Lack of snow, exposing plants to winter drying 5) Excessive snow lasting through the summer 6) Mechanical effects of high winds 7) Rapid heat loss at night 8) Excessive soil temperatures during the day 9) Drought. Three primary variables Temperature, Moisture, and Wind

Hawaii Birds

The main malarial vector, the mosquito (Culex quinquefasciatus), is conversely most common in the lowland areas. Because the native birds are much more susceptible to malaria than the introduced species, the malaria parasite is most common at intermediate elevations, where the geographical distributions of vectors and hosts overlap.

Potential Longevity

The maximum life span attainable by an individual of a particular species, is a limit set by the physiology of the organism, such that it simply dies of old age. Average longevity of individuals living under optimum conditions.

Theta-logistic Model

The modification of the original logistic equation to permit curved relationships between population density and the rate of population increase.

Gene Flow

The movement of alleles in space and time from one population to another.

Dispersal

The movement of individuals away from their place of birth or hatching or seed production into a new habitat or area to survive and reproduce.

Dispersal

The movement of individuals away from their place of birth or hatching or seed production into a new habitat or area to survive and reproduce. Thus, simultaneously an ecological process affecting distributions, and a genetic process affecting geographic differentiation.

Immigration

The movement of individuals into an area occupied by the population.

Emigration

The movement of individuals out of an area occupied by the population, typically the site of birth or hatching.

Coevolution

The mutual evolutionary influence between two species; each party in a co-evolutionary relationship exerts selective pressures on the other, thereby affecting each others' evolution, back and forth.

Methods for measuring relative density: Pelt records.

The number of animals caught by trappers has been used to estimate population changes in several mammals such as Canada lynx; some records extend back 300 years.

Methods for measuring relative density: Vocalization Frequency

The number of birds calls heard per 10 minutes in the early morning has been used as an index of the size of bird populations. The same method can be used for frogs, crickets, and cicadas.

Methods for measuring relative density: Roadside Counts

The number of birds observed while driving a standard distance has been used as an index of abundance, and the same technique can be used for other highly visible organisms.

Absolute Density

The number of individuals per unit area or per unit volume.

Phenotype

The observable physical characteristics of an organism.

Reid's paradox

The observed large discrepancy between the rapid rate of movement of trees recolonizing areas at the end of the ice age and the observed slow dispersal rate of tree seeds spreading by diffusion.

Realized Niche

The observed resources use of a species in the presence of competition and other biotic interactions; contrast with fundamental niche.

Physiological Ecology

The of limitations imposed by physical or chemical factors. the reactions of organisms to physical and chemical factors.

Krantz Anatomy

The particular type of leaf anatomy that characterizes C4 plants; plant veins are encased by thick-walled photosynthetic bundle-sheath cells that are surrounded by thin-walled mesophyll cells.

Methods for measuring relative density: Cover

The percentage of the ground surface covered by a plant as a measure of relative density has been used by botanists and by invertebrate ecologists studying the rocky intertidal zone. This is an especially important method for modular organisms.

Photoperiodism

The physiological responses of plants and animals to the length of day. Seasonal impact of day length on physiological responses.

Net reproductive rate is 1.0

The population is replacing itself. Ro of 1.5 mean the population is multiplying 1.5 times each generation. below 1.0 the population is not replacing itself.

Intrinsic Capacity for Increase

The potential rate of increase of a population that combines the life table and fertility schedule with the speed of development.

Photosynthesis

The process by which plants convert radiant energy from the sun into energy in chemical bonds. Carbon in the form of CO2 is taken up from the air and converted into organic compounds. We can measure the rate of photosynthesis by measuring the rate of uptake of CO2.

Natural Selection

The process in nature by which only the organisms best adapted to their environment tend to survive and transmit their genetic characteristics to succeeding generations while those less adapted tend to be eliminated.

Grazing Facilitation

The process of one herbivore creating attractive feeding conditions for another herbivore so there is a benefit provided to the second herbivore.

Stochastic Models

The realization that population trends are the joint outcomes of many individual probabilities.

Tens Rule

The rule of thumb that 1 species in 10 alien species imported into a country becomes introduced, 1 in 10 of the introduced species becomes established, and 1 in 10 of the established species becomes a pest. Introduced species occur in four "states" and undergo three "transitions". States (Imported - brought into the country, Introduced- found in the wild (feral), established- has a self-sustaining population, and Pest- has a negative economic impact). Transitions (Escaping- transition from imported to introduced, Establishing- Transition from introduced to established, Becoming a pest- Transition from established to pest)

Calvin-Benson cycle

The series of biochemical reactions that takes place in the stroma of chloroplasts in photosynthetic organisms and results in the first step of carbon fixation in photosynthesis. In the C3 pathway, CO2 from the air is first converted to 3-phosphoglyceric acid, a three-carbon molecule (hence the name C3)

Lotka-Volterra equations

The set of equations that describe competition between organisms for food or space; another set of equations describes predator-prey interactions.

Biogeography

The study of the geographical distribution of life on Earth and the reasons for the patterns one observes on different continents, islands, or oceans.

Physiological Ecology

The subdiscipline of ecology that studies the biochemical, physical, and mechanical adaptations and limitations of plants and animals to their physical and chemical environments.

Potential Evapotranspiration

The theoretical depth of water that would evaporate from a standard flat pan over a given time period if water is not limiting, largely dependent on temperature.

Maximum Reproduction

The theory that natural selection will maximize reproductive rate, subject to the constraints imposed by feeding and predator avoidance.

Handling Time

The time utilized by a predator to consume and individual prey item.

Plant Apparency Theory

The type of defenses the plant uses depends on how easily a herbivore can find the plant. Found to be inadequate.

r-selection

The type of natural selection experienced by populations that are undergoing rapid population increase in a relatively empty environment.

Criticisms of Liebig's Law

Too simplistic, saying at any point in time there is only one limiting factor for any process. The modern view is that a number of nutrients may be limiting simultaneously. Also, temperature can be limiting in one area and moisture can be limiting in another area. Liebig's Law is the foundation of complexity experiments.

Two ways of measuring Absolute Density

Total Counts and Sampling Methods

Individuals can be fitter for three reasons:

They may reproduce at a high rate, they may survive longer, or both.

Methods for measuring relative density: Number of artifacts

This count can be used for organisms that leave evidence of their activities, for example, mud chimneys for burrowing crayfish, tree squirrel nets, and pupal cases from emerged insects.

Methods for measuring relative density: Catch per unit fishing effort

This measure can be used as an index of fish abundance, for example, number of fish per 100 hours of trawling.

Hunting methods

Tied closely to habitat selection. Marginal habitats will not raise as many progeny and consequently will be selected against. Populations in marginal habitats may thus be sustained only by a net outflow of individuals from the preferred habitats.

Pines (Pinus spp.)

Tradeoff principle that species are constrained in their adaptations. This species is not drought tolerant.

Oak (Quercus spp.)

Tradeoff principle that species are constrained in their adaptations. This species is shade intolerant.

Adaptation

Trait that increase the fitness of individuals who have it/them.

Temperature and Moisture

Two major limiting factors to the distribution of life on earth. The rates of evaporation and transpiration depend primarily on temperature. The main factors controlling distribution of vegetation. Effects - Survival, Reproduction, Development of young organisms, Interactions with other organisms (Competition predation, Parasitism, Diseases) near the limits of temperature or moisture tolerance.

Three general types of survivorship curves

Type 1, 2, and 3

Hypothesis

Universal proposition that suggests explanations for some observed ecological situation. Ecology abounds with hypotheses.

Scientific Law

Universal statement that is deterministic and so well corroborated that everyone accepts it as part of the scientific background of knowledge. There are laws in physics, chemistry, and genetics, but not yet in ecology.

Principle

Universal statement that we all accept because they are mostly definitions, or are ecological translations of physical-chemical laws.

Critical Thermal Methodology

Used to determine temperature tolerances in fish. Fish are acclimated to a specific temperature and then subjected to a constant linear increase of decrease in temperature until a sublethal endpoint is reached. Lethal Temps can be estimated without killing the fish.

Optimality Model

Useful for thinking about what the costs and benefits are for a particular ecological strategy.

Environmental Heterogeneity

Variation in space in any environmental parameter such as soil pH or tree cover.

Aposematic

Warning coloration, indicating to a predator that this prey is poisonous or highly defended against attack.

Evolutionary

What is the ultimate cause? what is the role of natural selection? Example why is the earth worm shaped like it is.

Kin Selection

When an individual is able to increase the survival or reproduction of its relatives with whom it shares some of the same genes. Can act with individual selection aka inclusive fitness.

Natural Selection and Habitat

When there are habitat differences between successful and unsuccessful nests, the process of natural selection can operate to ultimately change nest-site distribution.

Distribution

Where organisms are found.

Resource Competition

Which occurs when a number of organisms utilize common resources that are in short supply.

Interference Competition

Which occurs when the organisms seeking a resource harm one another in the process, even if the resources is not in short supply.

Distribution and Abundance

Widespread species are typically more abundant. Example, moths collected throughout Britain, Similar patterns can be found in birds, plants, and many other groups, such that this positive relationship between distribution and abundance is another ecological generalization that can be called Hanski's Rule.

Geographic Ranges (Spatial Scales)

Worldwide, Continental, Region, Physiographic area, Cluster, Locality, Colony, and Clump

Root Zone complex interactions.

allelochemicals are an integral part of biotic interactions that affect distribution and abundance.

K-selected species

adapted to life at or approaching carrying capacity. Logistic growth curve. stable habitat/resources. long life, late reproduction. more investment in defenses for interspecific competition.

x

age

Type 2

aka Linear survivorship curve, implies a constant per capita rate of mortality independent of age. Many birds have this type.

Barriers

any geographic feature that hinders or prevents dispersal or movement across it, producing isolation.

Colonization rates

are driven not by the mean dispersal distance but by extreme dispersal events.

Temp & Precipitation

are main influences on the distribution of vegetation.

D=

average dispersal distance

Dispersal limitations

can be tested by transplant experiments.

Individuals of a species

cannot do everything in the best possible way.

Evolutionary: Ecology point of view:

considers organisms and relationships between organisms as historical products of evolution. (Ultimate causes).

Gametic Selection

have a genetic composition that differs from the diploid organisms that produce them.

Continental Climates

have large daily and seasonal temperature fluctuations.

Directional Selection

in which phenotypes at one extreme are selected against. Produces genotypic changes more rapidly than any other form, so most artificial selection is of this type. Best example is Darwin's finches. Larger Mean.

Fitness

is a measure of the contribution of an individual to future generations and can also be called adaptive value. Individuals have higher fitness if they leave more descendants.

Population

is a single species BIOTIC

Compromise (Adaptation)

is always a compromise because organisms have at their disposal only a limited amount of time and energy. There are trade-offs between adaptations such as wing shape in birds. A loon's wings are efficient for diving but not so efficient for flying.

Descriptive: Ecology point of view:

is mainly natural history and describes the vegetation groups of the world. ex.. temperate deciduous forests, tropical rain forests, grasslands, and tundra as well as the animals and plants and their interactions within each of these ecosystems. Foundation of all ecological science. Provides maps of geographical distributions and estimates of relative abundances of different species.

Environmental Studies

is the analysis of human impacts on the environment of the earth. Physical, Chemical, and Biological.

Portion of the life table needed to compute the capacity for increase

lx

n=

number of generations

dx

number of individuals dying during the age interval x to x+1

qx

per capita rate of mortality during the age interval x to x+1

Adaptation does not

produce the "best" phenotypes or "optimal" phenotypes, rather the "better" survive and constrained by four major forces.

R0=

reproductive rate per generation

In nature

we observe an actual rate of population change that is continually varying from positive to negative in response to changes within the population age distribution, social structure, and genetic composition, and in response to changes in environmental factors,