Ecology

The scientific study of the distribution and abundance of organisms and the interactions that determine distribution and abundance

Begon, Harper, Townsend, 2006, Ecology, Blackwell

Lecture outline

1. The evolution of life and life histories2. The flux of energy and matter3. Individuals and populations4. Ecological communities5. Positive and negative species interactions6. Trophic networks7. Distributions in time8. Distributions in space9. Function and diversity10. The human impact

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

Literature

Literature

http://www.ebooksdownloadfree.com/download/ecology-1.html

http://www.slideshare.net/marglema9/ecology-1

Ecological slideshows

Ecological e-books

The scientific method

The scientific study of the distribution and abundance of organisms and the interactions that determine distribution and abundance

Theory

HypothesesTestable

predictions

Observa-tions

Hypothesis testing

Hypothesis modification

DeductionTop down logic

Observa-tions

HypothesesTestable

predictions

Theory

InductionBottom up logic

A theory is used as a testable set of logically coherent hypothesesHypothesis are assumed of being falsifiable

The core of a theory is difficult to falsify because it can always be modified in a way to match empirical observations

Theory Observations

In the natural sciences we often do not test theories.We treat theories as an expectation under predefined conditions and are interest in the

deviation of reality from expectation.

Difference (Residual)

Hypotheses, testable

predictions

In this case the theory becomes untestable

and therefore unfalsifiable.

The new hypotheses do not directly follow from our theory. They contain

an empirical element.

Difference too large

Modify theory

Modify the theory to match observations

Conditions of the theory not met

The core of any theory is hard to falsify.

It is impossible to veryfy the core.

Theory predicts the number of insect species to rise to the power of 5/4 with plant species richness

𝑆 𝑖𝑛𝑠𝑒𝑐𝑡=𝑆𝑝𝑙𝑎𝑛𝑡❑

❑5/4

Gaston 1992

Residual

We do not test the theory. We use the theory and the empirical

data to study additional factors.We calculate the residuals and regress

them with the area under study.We detect four areas with much too

low and one area with too high species richness of insects.

We use c2 or Kolmogoroff Smirnoff tests to infer whether the theory matches the data.

Often these formal tests will reject the theory.

Ernst Haeckel(1834-1919)

The term ecology was coined 1866 by Ernst Haeckel in his habilitation lecture.

Oikos: home

Ecology deals with patterns and with processes in the living world.

Aims of ecology:

Describing the place of living beings in their environmentExplaining abundances, distributions, and interactions of living beingsPredicting the changes in the abundance and distribution of living beingsControling changes in the abundance and distribution of living beings

Autecology deals with the life history of single speciesPopulation ecology deals with the abundance and distribution of a group of interbreeding organismsCommunity ecology deals with a group of interacting speciesEvolutionary ecology deals with the evolutionary history of todays ecological systems

The basic units of ecological research are GenesIndividualsPopulationsSpecies

What is ecology?

The scientific study of the distribution and abundance of organisms and the interactions that determine

distribution and abundance

Distribution and abundance might relate to genes, individuals, populations, or speciesThe manifold of genes or species is called

diversity.Applied to all living beings we speak of

biodiversityAlfred Russel Wallace (1823-1913)

Charles Robert Darwin (1809-1882)

0

500

1000

1500

2000

2500

-600 -500 -400 -300 -200 -100 0

Num

ber o

f fam

ilies

z

K O S D C P T J Kr Pa N

Mass extinctions

E

Number of marine families

Species home range

Time

Allopatric speciation is generally slow

Peripatric speciation might be fast

Allopatric , peripatric, and sympatric speciation

Spatial breeding barrier

Allopatric and peripatric speciation: New species emerge by genetic divergence in geographically isolated regions

Sympatric speciation: New species emerge within the same habitat by any other breeding barrier. The include behavioural, resource use, or morphological barriers.

Tinamou

Ostrich

RheaSpotted Kiwi

North Island KiwiSouth Island Kiwi

Great Kiwi

Time80 0

Cassowary

Emu

Tinamou

The diversification of species

Australia

New Zealand

South Amercia / Africa

Low diversity of nine speciesComparably high genetic diversity

Today’s biodiversity is largely caused by evolutionary history and plate tectonics

Rhea

Cassowary

Zosterops abyssinicus

Zosterops poliogaster

Postglacial colonization of Europe

Hewitt G.M. 1999. Postglacial recolonisation of European biota. Biol. J. Linn. Soc. 68: 87-112.

During the last 10,000 years Central and Northern Europe was recolonised from multiple glacvial refuges where species survived the ice age.

The refuges are centres of gentic diversification.

Major refuges where: The MaghrebSpainTurkeySicilyCyrpusCrete

We reconstruct colonisation routs by the analysis of genetic diversity across Europe.

Because colonising populations are often small they are generically impoverished (founder effect).

Colonisation gradient

Founder effectsOrdered genetic loss

Relict populationsVicariant (scattered) genetic loss

Colonisation gradient

Carabus auronitens

Postglacial colonization of Europe

The allele - sites matrix is sorted according to allele richness

Popu-lations

Postglacial colonisation of European Tenebrionidae (Coleoptera)

Three major postglacial refuges with high numbers of endemics and high rates of glacial speciation

Three major colonisation routes

Reconstruction of postglacial colonisation using phylogenetic relatedness of species

Past and present fragmentation

Distribution of South American rainforest refugia (100,000 to 20,000 BP) based on the overlap of postulated refugia for birds, butterflies and plants. Shading represents probability

of locations being refugial. Whitmore, T.C. ,Prance, G.T. 187. Biogeography and Quaternary History in Tropical America. Blackwell.

Convergent evolution by similar selective pressures

Suboptimum

Ecological niches

Optimum

Water

Ligh

t Two niche dimensions of a plant

A given habitat filters species according to the abiotic conditions

Condition

Perfo

rman

ce

Performance of a species

Repro-duction

GrowthSurvival

G Evelyn Hutchinson, 1903-1991

The niche is the role a species plays in a community, rather than a habitat.

The niche is the sum of the habitat requirements that allow a

species to persist and produce offspring.

The niche is an n-dimensional hypervolume, where the

dimensions are environmental conditions and the resources that

define the requirements of an individual or a species to practise

Charles Elton, 1900-1991 Joseph Grinnell, 1877-1939

Profession

Place

Condition

Perfo

rman

ce

Ecological niches emerge from differences in performance along the gradient of habitat conditions

Generalist speciesSpecialist

species

Formally a niche is the place of a species within a multidimensional hypervolume spanned by all resources used by this species.

Generalist species have relatively broad niches in comparison to specialist species.

A habitat is the place where a species occurs. Do not mismatch habitat and niche!

Condition

Perfo

rman

ce

Fundamental nicheRealized

niche

Number of resources

Trop

hic p

ositi

on

Ground beetles (Carabidae) on Mazurian lake islands

Error bars denote a standard errorbasal

top

The carbon isotope ratio of body tissues (13C ⁄ 12C = δ13C) depends on resource width, while the nitrogen isotope ratio (15N ⁄ 14N = δ15N) increases in insects with trophic level.

Parts of the species are well segregated in trophic niche space, while another part of species highly overlaps in resource use.

The plot shows also three different guilds of species with similar resourse use.

Zalewski et al. 2013, Ann.Zool.Fenn

CA + D--H+ + E + S → (CH2O)n + DA + ES

The basic resources of life

(CH2O)nLight

Chemical reaction

Water, HydrocompoundsCO2

(CH2)nH2

Phototroph

Chemotroph

Organotroph

LithotrophAutotroph

Heterotroph

6CO2 + 6H2O + light + ADP → C6H12O6 + 6O2+ ATP Green plants, Cyanobacteria

C6H12O6 + C6H12O6 + O2 + ADP → (CH2O)n + CO2 + H2O + ATP Animals, fungi

CO2 + NH3 + O2 + ADP → (CH2O)n + HNO2 + H2O ATP Nitrosomonas bacteria

Facultative store of energy excess

Organic compounds

Waste

Carbon source

Proton source Energy

Energy storage

Organic compounds

Electron acceptor

Reduction Oxidation

Energy storage

Resources and feeding types

Energy source

Electron donator

Carbon source Trophic group

Light(Photo)

Organic(Organo)

Organic(Hetero) Photoorganoheterotrophs

Inorganic(Auto: CO2)

Photoorganoautotrophs

Inorganic(Litho)

Organic(Hetero) Photolithoheterotrophs

Inorganic(Auto: CO2)

Photolithoautotrophs

Radioactivity Inorganic(Litho)

Inorganic(Auto: CO2

Radiolithoautotrophs

Chemical compound(Chemo)

Organic(Organo)

Organic(Hetero) Chemoorganoheterotrophs

Inorganic(Auto: CO2)

Chemoorganoautotrophs

Inorganic(Litho)

Organic(Hetero) Chemolithoheterotrophs

Inorganic(Auto: CO2)

Chemolithoautotrophs

Animals, fungi, green plants

Cyanobacteria, green plants

Firmicutes heat tolerant Eubacteria

Purple non-sulfur bacteria

Iron bacteria, Archaea

Spirochaetes

Trophic niche spaces in eukaryotes

Mineralisers

Producers

Green plants

Animals

Fungi, slime moulds, animals

Fungivores

Herbivores

Omnivores

Parasites

Omnivores are animals that feed on

other animals and plants

The specific trophic needs of organisms define their trophic niche.

Trophic niches are generally not species specific. They are highly variable in time and space. Consumers

Saprovores

Carnivores

Reducers

Latin GreekHerbivore PhytophageCarnivore ZoophageFungivore MycetophageOmnivore PantophageSaprovore SaprophageMicrovore MicrophageBacteriovore Bacteriophage