Ecology

Niche breadth

A measurement of the range of resources utilized by a species

Niche overlap

A measure of how much species overlap with one another in the use of resources

Locus

A place, space or locality, especially a centre of an activity.

Effective population size

A population genetic concept of the number of breeding individuals in an idealized population that would maintain the existing genetic variability; it is typically much less than the observed population size

Ideal free distritubtion

A theoretical spatial spread of members of a population in which individuals take up areas in equal amounts of resources in relation to their needs, so all individuals do equally well

Hotspots of biodiversity

Areas of the earth that contain many endemic species (typically 1500) and as such are of important conservation value

Abiotic factors

Characterised by the absence of life; include temperature humidity, pH, and other physical and chemical influences

Biotic factors

Environmental influences caused by plants or animals

Homologous

Homologous chromosomes are chromosome pairs, one from each parent, that are similar in length, gene position and centromere location.

Umbrella species

IN conservation biology, species that serve as a proxy for entire communities and ecosystems, so that the entire system is conserved if they are conserved

Deme

Interbreeding group in a population, also known as local population

Source populations

Local populations in which the rate of production exceeds replacement so that individuals emigrate to surrounding populations

First principle of population regulation

No closed population stops increasing unless either the per capita birth rate or death rate is density dependent

Modular organisms

Organisms that have an indefinite growth form, such as plants or corals

Keystone species

Relatively rare species in the community whose removal causes a large shift in the structure of the community and the extinction of some species

Endemic species

Species that occur in one restricted area but in no other

What is Lack clutch size?

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

Heterogenity

The distribution of relative abundance among the species

Kin selection

The evolution of traits that increase the survival, and ultimately the reproductive success, of one's relatives

Hanski's Rule

The generalisation that there is a positive relationship between distribution and abundance, such that abundant species have wide geographical ranges

Intermediate disturbance hypothesis

The idea that biodiversity will be maximal in habitats that are subject to disturbances at a moderate level, rather than at a low or high level.

Match-mismatch hypothesis

The idea that population regulation in many fish is determined in the early juvenile stages by food supplies, so that if eggs hatch at the same time that food is abundant, many will survive, but if eggs hatch when food is scarce, many will die

Ambient Energy Hypothesis

The idea that species diversity is governed by the amount of energy falling on an area

Tragedy of the commons

The inherent tendency for overexploitation of resources that have free access and unlimited demand, so that it pays the individual to continue harvesting beyond the limits dictated by the common good of sustainability

Abundance

The number of organisms of a particular species in a general area

Biodiversity

The number of species in a community or region, which may be weighted by their relative abundances; also used as an umbrella concept for total biological diversity including genetic diversity within a species, species diversity (as used here), and ecosystem diversity at the community or ecosystem level or organisation

Community Structure

The species composition of an ecological community including the abundance of all the populations in the community.

Log-normal distribution

The statistical distribution that has the shape of a normal bell shaped curve when the x-axis is expressed in a logarithmic scale rather than an arithmetic scale

Limiting factor

a factor is defined as limiting if a change in the factor produces a change in average or equilibrium density

fecundity

an organisms potential reproductive capacity over a period of time, measured by the number of gametes produced

Adaptation

any alternation in the structure or function of an organism by which the organism becomes better able to survive and multiply in its environment

Stochastic

based on probability (eg coin flipping)

Second principle of population regulation

differences between two populations in equilibrium density can be caused by variation in either density-dependent or density-independent per capita birth and death rates

Environmentalism or Environmental studies is defined as...

"the analysis of human impact on the environment of Earth - physical, chemical and biological" much broader then ecology as it includes natural & social sciences.

Eugene ODUM (1963) defined Ecology as...

"the study of the structure and function of nature"

Ernst HAECKEL (1869) defined Ecology as...

"the total relations of the animal to both its organic and its inorganic environment."

The 3 Optimality Models

* Territorial Defence * Optimal Foraging * Optimal Migration

Ideal Despotic distribution

A theoretical spatial spread of members of a population in which the competitive dominant "aggressive" individuals take up the best resources or territories, and less competitive individuals take up areas or resources in direct relationship to their dominance status

Cost-benefit analysis

An assessment to determine whether the cost of an activity is less than the benefit that can be expected from the activity.

What does ANDREWARTHA (1961) neglet in his definition of ecology? ("the scientific study of the distribution and abundance of organisms"

Andrewartha (1961 leaves out the important idea of RELATIONSHIPS and interactions.

Territory

Any defended area

Barriers

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

What is the main difference between Ecology & Environmental studies?

Ecology is focused on the INTERRELATION of the natural world of ALL plants & animals (human considered another species). Environmental studies is the analysis of human impact on the environment of Earth.

What produces evolutionary changes?

Natural selection, is the mechanism that drive adaptive evolution. (Environments shape the evolutions that occur.)

What are the 4 biological disciplines closely related to ecology?

Physiology, Genetics, Behaviour & Evolution.

Relative benefit

The difference between the costs and benefits (=net benefit)

Kin Selection (levels of natural selection)

The evolution of traits that increase the survival, and ultimately the reproductive success, of ones relatives. If an individual is able to increase the survival or reproduction of its relatives with whom it shares some of the same genes, natural selection can operate through kin selection. (eg: Meerkats alarm call)

Hanski's Rule

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

Gene flow

The movement of allels in space and time form one population to another

Phenotype

The observable physical characteristics of an organism

Self-thinning rule

The prediction that the regression of organism size verus population density has a slope of -1.5 for plants and animals that have plastic growth rates and variable adult size

Optimal group size

The size that results in the largest relative benefit

Charles ELTON (1927) defined Ecology as...

"scientific natural history"

Maximum Reproduction?

(assocated with Lacks Hypothesis) The theory that natural selection will maximize reproductive rate, subject to the constraints imposed by feeding and predator avoidance

Group Selection (levels of natural selection)

(rarest in nature) Natural selection for traits that favour groups within a species irrespective of whether the traits favour individuals or not. Group selection can occur when populations of a species are broken up into discrete groups more or less, isolated from other such groups. Groups that contain less adaptive genes can become extinct, and the conditions for natural selection could occur at the level of the group, as well as at the level of the individual organism.

Optimality Models

(think economic terms - cost/benefit Analysis) Models that assume natural selection will achieve adaptations that are the best possible for each trait in terms of survival and reproduction.

Not applicable to the definition of 'fitness'

* Fitness is not absolute (same in different environments) * Fitness cannot be compared across species * Fitness is not only about reproduction (survival rates too) * Fitness is not a short term measure (measured across several generations) * Fitness is not about individual traits (whole-orgainisms survival and reproduction)

Define the process of natural selection

* Variation occurs in every group of plant and animal. Individuals of the same species are not identical in any population, as was observed in the breeding of domestic animals. * Every population of organism produces an excess of offspring. (The high reproductive capacity of plants and animals was well known to Malthus and Buffon long before Darwin) * Life is difficult, and not all individuals will survive and reproduce. * Among all the offspring competing for limited resources, only those individuals best able to obtain and use these resources will survive and reproduce. * If the characteristics of these organisms are inherited, the favoured traits will be more frequent in the next generation.

What are the three ways in which Natural Selection can occur?

*Directional Selection (evolution results from) *Stabilising election (occurs in ecological situations) *Disruptive Selection

What are the 4 levels of Natural Selection

*Gametic *Individual (Darwinian selection) *Kin *Group

Regulating factor

A factor is define as potientially regulating id the percentage of mortality caused by the factor increases with population density or if per capita reproductive rate decreases with population density

Promiscuity

A general term for multiple matings in organisms, called polyandry if multiple males are involved, or polygyny if multiple females.

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.

Disease

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

Law of diminishing returns

A principle of production that states that when one factor of production is increased, a point will be reached where each additional input will result in smaller and smaller outputs, or diminishing returns.

Ecological Specialization model

A proposed explanation for HAnski's rule postulating that species that exploit a wide range of resources become both widespread and common; these species are generalists; also called Brown's model

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

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 ideal despotic distribution)

What important ecological implications does Adaptation have?

Adaptation sets limits to the life cycle traits that determine distribution and abundance

Evolutionary 'Arms Race'

An arms race is a tit-for-tat evolution- a reciprocal interaction between species, in which as species A evolves better adaptations to exploit species B, the latter fights back by evolving adaptations to thwart the improvements in species A. (eg: hosts & parasites)

Density-dependent rate

As population density rises, births or immigration decrease or deaths or emigration increase, and consequently a graph of population density versus the rate will have a positive or negative slope

Trade-offs

Compromizes between two desirable but incompatible activities.

Define descriptive Ecology.

Descriptive (ecology) forms the essential foundation for Functional ecology, which asks HOW systems work.

What is the difference between descriptive ecology & evolutionary ecology?

Descriptive asks HOW systems work, Evolutionary asks WHY natural selection favours a particular solution.

What is the difference between the descriptive, functional & evolutionary approaches to Ecology?

Descriptive asks WHAT is happening.. Functional asks HOW is it happening.. Evolutionary asks WHY did his happen..

What are the three points of view we can approach the study of Ecology?

Descriptive, Functional & Evolutionary.

Discuss the relationship that exists between Ecology, Evolution and Natural Selection.

Ecology and evolution are intricately connected because evolution operates through natural selection, which is ecology in action.

Define Ecology, according to Krebs, using the 5 key components.

Ecology is the SCIENTIFIC STUDY of the INTERACTIONS that determine the DISTRIBUTION and ABUNDANCE of ORGANISMS.

Define Evolutionary Ecology.

Evolutionary (ecology) asks WHY natural selection favours a particular solution.

Define the 'evolutionary approach' to Ecology.

Evolutionary ecology studies ULTIMATE CAUSES- the historical reasons why natural selection has favoured particular adaptations we now see. This point of view considers organisms and relationships between organisms as historical products of evolution.

Define 'fitness'

Fitness is a measure of the contribution of an individual to future generations and can also be called adaptive value. Individuals have a higher fitness if they leave more descendants. This occurs for 3 reasons: 1. They may reproduce at a higher rate 2. They may survive longer 3. or both (relative term and applies to individual organisms within the same species)

4 critical foci of study in behavioural ecology

Foraging, anti-predator, social and mating behaviours (can all be analysed by cost-benefit analysis models).

Gametic Selection (levels of natural selection)

Gametes (eggs & sperm) have a genetic composition that differs form the diploid organisms that produce them. Gametes are produced in vast excess and may have characteristics that they transmit through the zygote and adult organism to the nest generation of gametes.

Proximate factors

HOW a particular trait is regulated by an individual in a physiological or biochemical manner

Behavioural Ecology

How an individuals bahviour is shaped by its social and physical environment, both past and present, and how specific behaviours affect its chances of surviving and reproducing. Asks how individual animals interact with other animals, plants and their physical environments to maximize fitness.

Control

In an experiemental desing 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.

Possible cause of promiscuity amongst animals

In the case of ethiopian wolves, promiscuity seems to be an adaption for paternity confusion (Wolff & Macdonald 2004)

Metapopulations

Local populations in patches that are linked together by dispersal among the patches, driven by colonization and extinction dynamics

Sink populations

Local populations in which the rate of production is below replacement level so that extinction is inevitable without a source of immigrants

Assumption of Natural Selection

Natural selection is assumed to have optimized the behaviour of individuals to achieve maximal fitness, and the job of the behavioural ecologists is to find the mechanisms by which this is achieved.

Disruptive selection

Natural selection that favours extreme traits values rather than intermediate values so that over time more extreme traits become more common

Stabilizing Selection

Natural selection that favours the norm, the most common or average trait in a population, so that the population mean stays constant

Directional Selection

Natural selection that favours traits either either above or below the average of the population, so that over time the average moves in one direction

Competition

Occurs when the number of organisms of the same or different species utilise common resources that are in short supply (exploitation) or when organisms harm one another in the process of acquiring these resources (interference)

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 therfore require a biological explanation

Allelopathy

Organisms that alter the surrounding chemical environment in such a way as to prevent other species from using it, typically with toxins or antiboitics

Allee effects

Population growth rates that decrease below replacement level at low population density, potentially leading to extinction

Ultimate Factors

Selective factors, the evolutionary explanation for an adaptation or why a trait is maintained in a population; opposite of proximate factors

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; contrasts with generalists

Define Lack's Hypothesis.

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

What is the Individual Optimization Hypothesis?

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

Define Coevolution.

The Evolution of 2 or more species that interact closely with one another, with each species adapting to changes in the other. (Occurs when a trait in species A has evolved in response to a trait of species B, which in tun had evolved in response to the trait in species A. Coevolution is specific and reciprocal). Where several species are involved, called diffuse coevolution.

fitness

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

Balance of nature

The belief that natural populations and communities exist in a stable equilibrium and maintain that equilibrium in the absence of human interference

Define the 'descriptive approach' to Ecology.

The descriptive point of view is mainly natural history and describes the vegetation groups of the world, and the plants and animals & their interactions within each of the ecosystems (eg: temperate deciduous forests, tropical rain forests, grasslands and tundra) (foundation of ALL ecological science)

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 (eg: temperature)

Define the 'functional approach' to Ecology.

The functional point of view is orientated towards the dynamics and relationships, seeking to identify and analyse general problems common to most or all of the different eco systems. (eg: deals with PROXIMATE CAUSES the dynamic responses of populations and communities to immediate factors in their environment.)

population regulation

The general problem of what prevents populations from growing without limit, and what determines the average abundance of 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 equatoriall latitudes, such that range sizes are smaller in the tropics

Define Evolution.

The genetic adaptation of organisms to their enviroment

Theta-logistic model

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

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

Immigrant

The movement of individuals into an area occupied by the population

Emigrant

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

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

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.

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.

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

What are the 3 approaches for analyzing Ecological problems?

Theorectical Approach, Laboratory Approach & Field Approach.

Matrix model

a family of models of population change based on matrix algebra, with the leslie matrix model being the best known

Logistic model

a specific population growth model based on the logistic equation that predicts a S-shaped population growth curve

Optimal foraging

any method of searching for and obtaining food that maximizes the relative benefit

Density-independent rate

as population density rises, the rate does not change in any systematic manner, so that a graph of population density versus the rate will have a slope ratio of zero

Probabilistic Model

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

Allel

one pair of characteristics that are alternative to each other in inheritance, being governed by genes situated at the same locus in homologous chromosomes; each of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Predation

the action of one organism killing and eating another

Habitat Selection

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

Herbivory

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