Adaption, Ecology and the Environment

11.1 The received view in Ecology11.2 History and Theory in Ecology11.3 The Balance of Nature11.4 Niches and Organisms11.5 Reconstructing Niches11.6 Unfinished Business

11.1 The Received View in Ecology

● Ecology versus Evolutionary Theory● Ecology as a description of Environment● The concept of the Niche

11.1 Ecology versus Evolutionary Theory

ecology: short term view on a local area or local community

11.1 Ecology versus Evolutionary Theory

ecology: short term view on a local area or local commuity

evolutionary theory:long term global view

11.1 Ecology

ecology is a way of explaining evolutionary fitnesses of organisms;and so it is formulating the source laws of evolutionary biology;

11.1 Ecology as a description of Environment

it describes the environment where evolutionary changes take place;

11.1 The concept of the Niche

Elton's concept of a niche:a way of making a living in an organic community;

11.1 The concept of the Niche

Elton's concept of a niche:a way of making a living in an organic community;different organisms can play the same causal roles indifferent communities;grazers->predators->scavengers->seed eaters...

11.1 The concept of the Niche

Elton's concept of a niche:a way of making a living in an organic community;different organisms can play the same causal roles indifferent communities;grazers->predators->scavengers->seed eaters...still members of the same niche:communities that are widely scattered in space and time but functionally similar

11.2 History and Theory in Ecology

●Signals sent by history●Island biogeographie

11.2 Signals sent by History

reconstruction of history by its traces in the present

signals in the form of jointly inherited features

convergence and divergence are noise and disturb the “signal“

11.2 Island Biogeography

an ahistorical view by MacArthur:diversity only depends on the size of an „island“ and its distance from immigration sources

11.2 Island Biogeography

an ahistorical view by MacArthur:diversity only depends on the size of an „island“ and its distance from immigration sources=>time and accidental historical developments play a minor role

11.2 Island Biogeography

an ahistorical view by MacArthur:diversity only depends on the size of an „island“ and its distance from immigration sources=>time and accidental developments play a minor role

do islands of the same size and physical similarityhave simular communities?

11.3 The Balance of Nature

communities can get close to reach equilibrium conditions

but they need internal checks and balances(competion, predation, parasitism, ...)

there is always the possibility of devastation from outside

in reality equilibrium is never reached

the return time from disturbance is shorter than the life span of the community's dominant elements

11.4 Niches and Organisms

Classic view:organisms are shaped to fit their niche

11.4 Niches and Organisms

Classic view:organisms are shaped to fit their niche

Lewontin: organisms construct environments “as much as”(?) environments construct organisms

niches are defined by their occupants, they do not exist by themselves

Two concepts of environment

Godfrey-Smith: properties defined by an organism(e.g. territory)other properties(e.g. temperature)

Three concepts of environment

Robert Brandon:external environment(physical factors, biotic and abiotic)

Three concepts of environment

Robert Brandon:external environment(physical factors, biotic and abiotic)

ecological environment(factors that affect the organism's reproductive output)

Three concepts of environment

Robert Brandon:external environment(physical factors, biotic and abiotic)

ecological environment(factors that affect the organism's reproductive output) selective environment (ctitical for evolutionary theory)(factors that differentially affect the reproductive output across a range of individuals)

11.5 Reconstructing Niches

The authors prefer Lewontin's concept of the Nichebut would make some extensions

11.5 Reconstructing Niches

The authors prefer Lewontin's concept of the Nichebut would make some extensions

The dimensions of the niches should be determined by the clade and not by the species that belongs to it

=> a more generalistic and long-lasting solution

11.6 Unfinished Business

the nature of ecology's units is problematic

11.6 Unfinished Business

the nature of ecology's units is problematic

communities in small islands can de recognized

but what about an area with a smooth change from closed forest to woodland and from woodland to grassland?

there will be no well defined membership in such communities...