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
Ecology is the scientific study of the distribution and abundance of organisms and the interactions that determine distribution and abundance • Lecture outline • The evolution of life and life histories • The flux of energy and matter • Individuals and populations • Ecological communities • Positive and negative species interactions • Trophic networks • Distributions in time • Distributions in space • Function and diversity • The human impact
Ecologicalslideshows http://www.slideshare.net/marglema9/ecology-1 Ecological e-books http://www.ebooksdownloadfree.com/download/ecology-1.html
The scientificstudy of the distribution and abundance of organisms and the interactionsthatdeterminedistribution and abundance Distribution and abundancemightrelate to genes, individuals, populations, orspecies The manifold of genesorspeciesiscalleddiversity. Applied to alllivingbeings we speak of biodiversity Charles Robert Darwin (1809-1882) Alfred Russel Wallace (1823-1913) Number of marinefamilies
Allopatric , peripatric, and sympatric speciation Allopatric speciation is generally slow Species home range Spatial breeding barrier Peripatric speciation might be fast Time 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.
The diversification of species Tinamou SouthAmercia / Africa Ostrich Tinamou Rhea New Zealand Spotted Kiwi Great Kiwi North Island Kiwi Rhea South Island Kiwi Australia Cassowary Emu 80 Time 0 Cassowary Lowdiversityof ninespecies Comparably high geneticdiversity Today’sbiodiversityislargelycaused by evolutionaryhistory and platetectonics
Zosterops poliogaster Zosterops abyssinicus
Postglacial colonization of Europe 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 Maghreb Spain Turkey SicilyCyrpus Crete We reconstruct colonisation routs by the analysis of genetic diversity across Europe. Because colonising populations are often small they are generically impoverished (founder effect). Hewitt G.M. 1999. Postglacial recolonisation of European biota. Biol. J. Linn. Soc. 68: 87-112.
Postglacialcolonization of Europe Carabusauronitens Colonisation gradient Foundereffects Orderedgeneticloss Popu-lations Relictpopulations Vicariant(scattered) geneticloss Colonisation gradient The allele - sitesmatrixissortedaccording to allele richness
Postglacial colonisation of European Tenebrionidae (Coleoptera) Reconstruction of postglacial colonisation using phylogenetic relatedness of species Three major colonisation routes Three major postglacial refuges with high numbers of endemics and high rates of glacial speciation
Ecological niches Charles Elton, 1900-1991 Joseph Grinnell, 1877-1939 G Evelyn Hutchinson, 1903-1991 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 The niche is the sum of the habitat requirements that allow a species to persist and produce offspring. The niche is the role a species plays in a community, rather than a habitat. Profession Place Two niche dimensions of a plant Performance of a species Suboptimum Light Performance Optimum Condition Repro-duction Growth Water Survival A given habitat filters species according to the abiotic conditions
Specialist species Generalist species Performance Condition Ecological niches emerge from differences in performance along the gradient of habitat conditions 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! Fundamental niche Performance Realized niche Condition
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. Ground beetles (Carabidae) on Mazurian lake islands top Trophic position Error bars denote a standard error basal Zalewski et al. 2013, Ann.Zool.Fenn Number of resources 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.
Trophic niche spaces in eukaryotes 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. Animals Consumers Carnivores Green plants Parasites Herbivores Producers Omnivores Fungivores Omnivores are animals that feed on other animals and plants LatinGreek Herbivore Phytophage Carnivore Zoophage FungivoreMycetophage Omnivore Pantophage SaprovoreSaprophage Microvore Microphage Bacteriovore Bacteriophage Mineralisers Saprovores Reducers Fungi, slime moulds, animals