Ecology I – PEN10503
4) Individuals differ in the number of descendants
LECTURE 1: ECOLOGY AND EVOLUTION: THE
and therefore contribute differently to the
ORIGIN AND DISSEMINATION OF SPECIES hereditary characteristics of a next generation
WHAT IS ECOLOGY AND WHAT IS ITS IMPORTANCE?
ecology: the study of the interaction of organisms survival of the fittest:
that interact with other organisms and biospheres 1) variation for a trait: difference in characteristics
and explain their patterns 2) heritability: the characteristic is passed on to
ecology: the study of the distribution and abundance the offspring
of organisms, the interactions that determine that 3) differential reproduce success: offspring with
distribution and abundance, the unbeneficial trait dies; offspring with the
and the relationship between organisms and beneficial trait survives
the transformation and flux of energy and fitness: relative contribution of an individual to the
matter next generation
organisms influence surroundings – surroundings genotype: all genetic characteristics of an
influence organisms – organisms influence other individual that together determine the
organisms characteristics of the individual
the central variable of ecology is distribution: phenotype: the actual expressed characteristics
dispersion (where?), density (how many?), of the individual
characteristics (adaptations to environment) phenotypic plasticity: the extent to which
ecology is part of a lot of global goals and is a variation in phenotypes of an individual is
component of urban areas expressed depending on the environment (how
ecology starts with much the phenotype is determined by the
1) observation environment)
2) discover patterns there are different genotypes with two alleles: PP
3) ask questions (+) – Pp (+) – Pp (+) – pp (-)
4) unraveling underlying processes all possibilities:
this is done by observations, experiments, models, - different genotype, same phenotype, no
and molecular and chemical analysis environmental influence
an ecological question is answered in 2 ways: - different genotype, different phenotype, no
1) proximate explanation: cause-effect (how?) environmental influence
the organism can endure/need … and thus - different genotype, different phenotype,
move to that environment environmental influence (phenotypic
2) ultimate explanation: function; evolutionary plasticity)
processes (why?) - different genotype, different phenotype,
the organism has adapted to the environment environmental influence on one genotype
to protect itself from predators and biological (phenotypic plasticity)
aspects - ex: fish: color difference:
- color: attract females + high predation
ECOLOGY AND EVOLUTION: SPECIATION AND
- neutral: not attract many females + low
predation
DISPERSION
evolution within a species is determined by many
processes on earth that led to the environmental factors:
conditions as they are now: environment, genetic drift, co-evolution
1) volcanic atmosphere co-evolution: mutual selection of organisms in
2) anaerobic bacteria: do not tolerate O2 interaction: evolutionary change that occurs
3) aerobic bacteria (photosynthesis: O2 released between species as they interact with one another:
and ozone layer formed to shield the earth one species puts pressure on another species;
against UV light); first, no O2 level rise other species adapts
because it bound to iron rocks ex: flower produces toxins, butterfly and rups can
4) anaerobic organisms - reproduction do detoxification (resistance)
5) aerobic organisms - reproduction environment: difference in environment and
colonization on land: barriers due to dehydration difference in genotype causes group 1 to have a
and gravity different characteristic than group 2 and thus lives
in a different environment
evolution through natural selection: rules: ➔ little exchange and strong selection between
1) Individuals within a population are not identical groups lead to ecotypes:
2) Part of the variation between individuals has a ecotypes: subspecies: populations of a species
genetic basis and is heritable (overerfbaar) with a different phenotype adapted to local
3) Not all individuals are able to reproduce, so conditions; distinguishment in species
populations contain a subset of the possible
descendants of the previous generation
, Ecology I – PEN10503
speciation: long-term isolation can lead to 3 types of evolution:
speciation: no hybrids with fertile offspring occur
between the species:
different genetic characteristics -> different
environments -> little exchange and strong
selection -> groups 1 and 2 cannot have together
fertile offspring -> 2 species
2 types of speciation:
1) allopatric speciation: different species arise
in isolation (mountain, river)
ex: Darwin finches: 18 species of birds: the
colonization of new islands and adaptations to
new food source 1) parallel evolution:
2) sympatric speciation: different species arise starting point: common ancestor, but
without isolation (because of different causes: geographically separated
changing niche, different phenotype, different organs: analogue and homologue
food etc) example: placental mammals and marsupials
(until 100 million years ago)
3 effects of allopatric speciation
subspecies: populations of a species that differ in 2) divergent evolution:
characteristics, but produce fertile starting point: common ancestor
offspring when hybridized (a population of a organs: homologous organs
species is genetically to an extent isolated from example: development of forelimbs in mammals
other populations of the species)
ecotypes: (similar to subspecies) populations of a 3) convergent evolution:
species with a different phenotype starting point: very different ancestors
adapted to local conditions (a subgroup of organs: analogue
individuals of a species that are adapted to a local example: wings in animals
environmental condition)
ring species: a complex of subspecies that can analogue organs: organs of both species have
interbreed with adjacent populations, but the same form and function
for which "end" populations are too distantly homologue organs: organs of both species
related to interbreed developed from the common ancestral organ
plate-tectonics: causes different species (plants components and thus functions change over time:
and thus animals) to occur in certain regions: length, type of animal (grazer/browser)
zoogeography Species compositions and characteristics are
phytochoria: climate is the determining factor for subject to change over time (evolution): therefore,
species composition (an area with a relatively evolutionary history must be taken into account in
uniform composition of species) ecology
zoography: plate tectonics determined the
species composition in different 6 different areas
[zoography is not phytochoria] molecular and evolutionary ecology
DNA: code of life: molecules with information
about hereditary characteristics;
DNA varies a lot because of mutations (change of
ATCG, and thus change in characteristic)
the 3 major forces in evolution:
1) mutations (random, slow)
adds alleles to the population
2) selection (environment, slow)
subtracts alleles from the population ->
decreases genetic diversity
3) genetic drift (random, fast)
subtracts alleles from the population ->
6 regions: Nearctic – Neotropical – Palearctic – decreases genetic diversity
Ethiopian – Oriental – Australian
endemic species: species that only occur locally genetic drift: the number of successful alleles will
(Madagascar) increase in the population and the number of
unsuccessful alleles will decrease
, Ecology I – PEN10503
selection: environment determines which groups - Temperate grassland
survive - Desert
- Mediterranean vegetation, chaparral
Molecular techniques in ecology: - Mountains
Polymerase Chain Reaction (PCR): multiple Mediterranean vegetation: shrubs; biome of any
copying of small pieces of DNA; makes dense scrubland composed of broad-leaved
analysis of the sequence possible evergreen shrubs, bushes, and small trees (<2.5
PCR on mitochondrial DNA: kinship analysis, m); climate with hot dry summers and mild wet
mtDNA is usually transferred from the mother winters. named macchie / maquis / garigue (at
to daughter without recombination. Mediterranean) or chaparral (in America); also
PCR on nuclear DNA: possible to trace pairings present in Africa
within a population.
Microsatellite DNA: a set of microsatellites yields biomes are determined by structures / shapes
a DNA fingerprint to track the dispersion of of the vegetation (different layers) and NOT the
offspring of individuals within a population species composition; it is about the
molecular research: PCR pathway: characteristics of the area
1) collect DNA sample from individuals
2) select identical genetic markers for all biome is determined by climatic factors:
individuals temperature and rainfall:
3) PCR the genetic markers low T, low rainfall
4) do genotyping (the process of determining
differences in the genetic sequences)
5) interpret genetic data ecologically
Genetic divergence within a population: markers
with a high mutation rate
The colonization of the environment over time (e.g.
10.000 years): markers with a low mutation rate
in a population: high mutation rate
when colonizing: low mutation rate
determine whether it is a species or a hybrid:
high T, high rainfall (more variation in rainfall)
hybrid: cross between two individuals of one/two
There are eight terrestrial biomes (biomes on land)
species
ex: biomes in Russia:
species: new species developed by evolution
The further away from the pole, the higher the T,
the more evaporation, the longer the growing
LECTURE 2: ENVIRONMENTAL CONDITIONS, season, the more irradiation (sun hours), the lower
RESOURCES, BIOMES the groundwater table; rainfall first increases and
then decreases
biomes climate and soil processes both help to determine
biomes: groups of ecological communities on the vegetation present + land planning
earth; vegetation areas;
ecological community: all living organisms in a
specific area (during a certain period of time)
biomes:
- Tundra
- Boreal forest
- Temperate forest
- Tropical rain forest
- Tropical seasonal forest and savanna
tundra: enough water is present, a lot of organic
materials
temperate regions: podzolic soils
steppe: contains a lot of organic material in the soil
dessert: mottling in the soil (because of
evaporation)
savanna (C4 grasses)
