Ecology-1: A Summary of Lectures (Wageningen University & Research) 2019-2020 PDF

lOMoARcPSD|33505872 Ecology-1 - Samenvatting van de lectures Ecology I (Wageningen University & Research) Scannen om te openen op Studeersnel Studeersnel wordt niet gesponsord of ondersteund door een hogeschool of universiteit Gedownload door Sophie Ho...

lOMoARcPSD|33505872 Ecology-1 - Samenvatting van de lectures Ecology I (Wageningen University & Research) Scannen om te openen op Studeersnel Studeersnel wordt niet gesponsord of ondersteund door een hogeschool of universiteit Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 ECOLOGY-1 A SUMMARY OF THE LECTURES PEN10503 2019-2020 P1 Gijs Bauer (100525038120) Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 CONTENTS Lecture 1: Ecology and Evolution--------------------------------------------------------------------------1 Introduction-------------------------------------------------------------------------------------------------------1 History of the earth--------------------------------------------------------------------------------------------2 Evolution------------------------------------------------------------------------------------------------------------2 Evolution through natural selection--------------------------------------------------------------------3 Evolution within species-------------------------------------------------------------------------------------3 Plate tectonics and dispersion of species-------------------------------------------------------------4 Lecture 2: Biomes-------------------------------------------------------------------------------------------------5 Biomes---------------------------------------------------------------------------------------------------------------5 Plant functional types:----------------------------------------------------------------------------------------5 Resources and conditions-----------------------------------------------------------------------------------6 Role of temperature-------------------------------------------------------------------------------------------7 Role of temperature in exothermic organisms-----------------------------------------------------7 Role of temperature in endothermic organisms---------------------------------------------------8 Resources for plants-------------------------------------------------------------------------------------------9 Resources for animals--------------------------------------------------------------------------------------10 Competition-----------------------------------------------------------------------------------------------------11 Lecture 3: Populations-----------------------------------------------------------------------------------------12 Introduction-----------------------------------------------------------------------------------------------------12 Counting individuals-----------------------------------------------------------------------------------------12 Population and life history: Repoduction-----------------------------------------------------------13 Dispersal and migration------------------------------------------------------------------------------------13 Intraspecific competition and migration growth------------------------------------------------14 Grimes plant strategies-------------------------------------------------------------------------------------15 Predation---------------------------------------------------------------------------------------------------------15 Optimal foraging----------------------------------------------------------------------------------------------16 Metapopulations-----------------------------------------------------------------------------------------------17 Lecture 4: Interspecific Competition and Species Richness----------------------------------18 Succession-------------------------------------------------------------------------------------------------------18 Competition-----------------------------------------------------------------------------------------------------18 Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Lotka-Volterra model----------------------------------------------------------------------------------------19 Niches--------------------------------------------------------------------------------------------------------------19 Species richness and biodiversity----------------------------------------------------------------------19 Spatial factors (Island Theory)--------------------------------------------------------------------------21 Lecture 5: Energy Fluxes and Cycles-------------------------------------------------------------------22 Introduction-----------------------------------------------------------------------------------------------------22 Food webs--------------------------------------------------------------------------------------------------------22 Energy: (stock) reservoirs and fluxes----------------------------------------------------------------22 Primary production-------------------------------------------------------------------------------------------23 Secondary production---------------------------------------------------------------------------------------24 Lecture 6:-----------------------------------------------------------------------------------------------------------26 Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Ecology-1, A summary of the lectures LECTURE 1: ECOLOGY AND EVOLUTION INTRODUCTION Ecology: knowledge of the relationships between organisms and their environment.  Ecology is about understanding interactions between individuals and its environment. Organisation levels:  Organisms, individual  Population  Ecological community  Ecosystem  Landscape  Biome  Biosphere Ecology is about understanding interactions between individuals and its environment. Surroundings effect organisms and organisms affect the surrounding. It starts with: 1. Observation. 2. Discovering patterns. 3. Asking questions (based on the patterns). 4. Understanding and unravelling underlying processes. Approaches 1. Observations in the field. 2. Controlled field or lab experiments. 3. Mathematical models. 4. Molecular and chemical analysis. 5. Statistics: reliability of findings. Proximate explanation: “how” question  Function of behaviour of individuals. Ultimate explanation: “why” question  Evolutionary explanation of behaviour of individuals. 1 | Page Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Ecology-1, A summary of the lectures HISTORY OF THE EARTH 4.5 billion years old  Vulcanic activity. o harsh environment. o anaerobic organisms (no oxygen).  Photosynthesis. o oxygen released into atmosphere. o first bound to iron-bearing rock. o then rock was saturated and oxygen gets free into air.  Aerobic organisms. o first bacteria/protozoa. o sponges and fungi. o corals. o vertebrates.  Life on land. o Dehydration and gravity were new challenges that life had to overcome. Most important events  advent of anaerobic bacteria.  photosynthesis.  free oxygen.  ozone as shield against UV.  sexual reproduction (boosted diversity).  life on land. Most important people in evolution: Darwin and Wallace.  Theory of natural selection (survival of the fittest). EVOLUTION 1. Parallel evolution  common ancestor, but geographically separated.  Organs:  analogue: the same form and function.  homologue: body plan different but from the same ancestral organ. 2. Divergent evolution  common ancestor 2 | Page Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Ecology-1, A summary of the lectures  Organs:  homologue: body plan different but from the same ancestral organ. 3. Convergent evolution  very different ancestors.  Organs:  analogue: : the same form and function. Cause of variation: mutations. 1. Mutation: adds alleles to the population. (+ genetic variation)  random and slow. 2. Selection: subtracts alleles from the population. (- genetic variation)  environment and slow. 3. Genetic drift: subtracts alleles from the population. (- genetic variation)  random and fast. EVOLUTION THROUGH NATURAL SELECTION  Individuals within a population are not identical.  Part of variation between individuals has a genetic basis and is heritable.  Not all individuals are able to reproduce.  Not all individuals contribute equally. o affected by environment. Fitness: relative contribution of an individual to next generation. Genotype: all genetic characteristics of an individual that together determine the characteristics of the individual. Phenotype: the actual expressed characteristics of the individual. Phenotypic plasticity (flexibility): the extent to which variation in phenotypes of an individual is expressed depending on the environment. (different environment, different phenotype) Co-evolution: mutual selection of organisms in interaction. EVOLUTION WITHIN SPECIES Little exchange and strong selection leads to ecotypes. Ecotypes: populations of a species with a different genetically determined phenotype adapted to local conditions. Long term isolation can lead to speciation. 3 | Page Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Ecology-1, A summary of the lectures Speciation: No hybrids (the result of interbreeding between two animals or plants of different taxa) with fertile offspring occur between the species.  Example: 2 species of gulls. Subspecies: populations of a species that differ in characteristics, but produce fertile offspring when hybridised. Ring species: complex of subspecies which can interbreed with adjacent (neighbouring) populations, but for which “end” populations are too distantly related to breed. Allopatric speciation: species arisen in isolation Sympatric speciation: species arise when they live side by side Figure 1. allopatric phase  secondary contact  sympatric phase PLATE TECTONICS AND DISPERSION OF SPECIES There are 6 zoogeographic regions due to plate tectonics (continental drift). 280 million years ago  only 1 continent (Pangea) Flora kingdoms are also the result of continental drift but borders are not the same as the zoogeographic regions because plants populated the land earlier (continents were more together which gave plants the chance to spread).  on a local scale, flora districts can be distinguished. Environmental factors are important in determining which species live where. European phytochoria: climate is the determining factor for species composition. Endemic species: species that only occur locally.  Example: Maki’s in Madagascar. 4 | Page Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Ecology-1, A summary of the lectures 5 | Page Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Ecology-1, A summary of the lectures LECTURE 2: BIOMES BIOMES Biomes: groups of ecological community on earth. Ecological community: all living organisms in a specific area.  Example: desert, grasslands, tropical forest, taiga & tundra. Figure 2 Triangle of biomes: temperature and precipitation as determinant factors  8 terrestrial (on land) biomes.  tropical regions  more variation in rainfall. For biomes, the vegetation structure for biomes is distinctive (not on the species composition).  EXAM Potential vegetation: vegetation that should be present in a biome. Current vegetation: vegetation that actually there.  influenced by humans  replacement communities instead of potential vegetation.. PLANT FUNCTIONAL TYPES:  Raunkiaer’s life forms in plants. 6 | Page Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Ecology-1, A summary of the lectures  Are used for distinction between biomes. o This distinction is made depending on where the grow points (buds) of plants are.  high in trees.  low in shrubs.  beneath ground level in bulbs/rootstock plants.  Raunkiaer’s life forms and biome structure both related to climate.  In models, plant functional types are used instead of species. o Too much information and not all are known. The life forms are: 1. trees 2. shrubs 3. herbs 4. bulbs/rootstock plants 5. annuals (annuals: plants that survive unfavourable periods as seeds) Soils also have impact on biome distinction, but not as much as plants.  Example: West-Africa and South-America have different soils and different vegetation but same climate. RESOURCES AND CONDITIONS Environmental conditions: abiotic environmental conditions that vary over time and in space, to which different organisms response differently.  are variable.  are not consumable. Resource  are variable.  are consumable. Resource: abiotic and biotic condition in space and time that are consumed. 7 | Page Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Ecology-1, A summary of the lectures Environmental conditions for animals  temperature.  humidity.  pH (mainly indirect).  salinity.  level of harmful substance.  light. Environmental resources for plants  temperature.  pH (mainly indirect effects).  level of harmful substance.  salinity. Light is a resource for plants. Climate envelope: climate conditions in which a species can survive.  changes over time due to global warming, ice age, etc. ROLE OF TEMPERATURE Signalling effect: vernalisation (germination after a cold period) or extreme factor (frost). Exothermic (cold blooded):  great influence on metabolic rate.  lifecycle determined in physiological time. Endothermic (warm blooded):  not a great influence on metabolic rate.  lifecycle not influenced by temperature. ROLE OF TEMPERATURE IN EXOTHERMIC ORGANISMS  great influence on metabolic rate, growth and development 8 | Page Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Ecology-1, A summary of the lectures  Q10: a 10 degrees change in temperature results in a factor 2 to 3 change in rate of development Physiological time: product of temperature and time  determines lifecycle Calculation of physiological time Physiological time = V * t Only in exothermic V = c (T-a) c = proportionality constant Development rate V a = threshold value (%/d y) t = time in days V = development rate in angle %/day a= Temperature T (degrees el ) Physiological time: determination of accumulated temperature Physiological time is the product of temperature V and * t =time: c * (T-a) 100% development means accumulated temperature completed  temperature sum All above NOT applicable to endothermic organisms  Do not have a temperature sum  Are not influenced by temperature  EXAM QUESTION If predator is endothermic and prey is exothermic, climate change causes NO problem for the predator. ROLE OF TEMPERATURE IN ENDOTHERMIC ORGANISMS  Regulation by internal thermostat.  requires much additional energy. W 9 | Page 0 75 ¿ Gedownload door Sophie Holzhaus ([email protected])  lOMoARcPSD|33505872 Ecology-1, A summary of the lectures Energy requirement: a = constant (always