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
1. The evolution of life and life histories
2. The flux of energy and matter
3. Individuals and populations
4. Ecological communities
5. Positive and negative species interactions
6. Trophic networks
7. Distributions in time
8. Distributions in space
9. Function and diversity
10. The human impact
Literature
Literature
Ecological slideshows
http://www.slideshare.net/marglema9/ecol
ogy-1
Ecological e-books
http://www.ebooksdownloadfree.com/d
ownload/ecology-1.html
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 species
The manifold of genes or species is called
diversity.
Applied to all living beings we speak of
biodiversity
Charles Robert
Darwin
(1809-1882)
Alfred Russel
Wallace
(1823-1913)
Number of marine families
2500
Number of families
z
Mass extinctions
2000
1500
1000
500
0
-600
-500
E
K
-400
O
S
D
-300
C
P
-200
T
J
-100
Kr
0
Pa N
Allopatric , peripatric, and sympatric speciation
Allopatric speciation is generally slow
Spatial breeding barrier
Species
home
range
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
South Amercia /
Africa
Ostrich
Rhea
Spotted Kiwi
Great Kiwi
North Island Kiwi
South Island Kiwi
Cassowary
New
Zealand
Australia
80
Time
Tinamou
Rhea
Emu
0
Cassowary
Low diversity of nine species
Comparably high genetic diversity
Today’s biodiversity is largely caused by evolutionary history and plate tectonics
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.
We reconstruct
colonisation
routs by the
analysis of
genetic diversity
across Europe.
Because
colonising
populations are
often small they
are generically
impoverished
(founder effect).
The refuges are
centres of gentic
diversification.
Major refuges where:
The Maghreb
Spain
Turkey
Sicily
Cyrpus
Crete
Hewitt G.M. 1999. Postglacial recolonisation of European biota.
Biol. J. Linn. Soc. 68: 87-112.
Postglacial colonization of Europe
Carabus auronitens
Colonisation gradient
Founder effects
Ordered
genetic loss
Populations
Relict
populations
Vicariant
(scattered)
genetic loss
Colonisation gradient
The allele - sites matrix is sorted according to allele richness
Postglacial colonisation of European Tenebrionidae (Coleoptera)
Reconstruction
of postglacial
colonisation
using
phylogenetic
relatedness of
species
Three major postglacial refuges with high numbers of
endemics and high rates of glacial speciation
Three major
colonisation routes
Ecological niches
Charles Elton, 1900-1991
Joseph Grinnell, 1877-1939
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.
Profession
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
Two niche dimensions of a
plant
Optimum
Suboptimum
Water
A given habitat filters species according
to the abiotic conditions
Performance
Light
Place
Performance of a species
Reproduction
Growth
Survival
Condition
Performance
Specialist
species
Generalist species
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.
Performance
A habitat is the place where a species occurs.
Do not mismatch habitat and niche!
Realized
niche
Fundamental
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
Trophic position
top
basal
Error bars denote a standard error
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
Carnivores
Green plants
Producers
Latin
Greek
Herbivore
Carnivore
Fungivore
Omnivore
Saprovore
Microvore
Bacteriovore
Phytophage
Zoophage
Mycetophage
Pantophage
Saprophage
Microphage
Bacteriophage
Herbivores
Parasites
Fungivores
Omnivores
Mineralisers
Saprovores
Fungi, slime moulds,
animals
Omnivores are
animals that feed on
other animals and
plants