Biology Year 2 Semester 1 Flashcards
How do plants affect dissolved O2 levels in shallow urban rivers during the night and day?
Night - plants respire - consuming O2
Day - plants photosynthesise - producing O2
What is lentic water?
Low movement/stationary
Closed systems
Lakes, ponds and pools
What is lotic water?
Flowing water
Rivers, streams, springs
Open system
Catchment areas influence river contents
Transfers and dilutes materials/chemicals
Describe wetlands
Standing water - support aquatic plants (macrophytes), marshes, swamps and bogs
Interface of terrestrial or aquatic ecosystems
How do wetlands affect stream hydrology
Impede flow
Enhance sediment deposition
Wetlands; what did Horne & Goldman (1994) find?
Transforms inflowing nutrients into organic forms which are later released downstream as detritus
Describe plankton ecology? and give examples
Floating
Movement (current dependant)
Phytoplankton and Zooplankton
What is an epibenthos organism?
Lives at surface of the bottom of bodies of water - attached or clinging to plants
What is a nekton organism?
Swimming and able to navigate at will
eg. fish and squid
Describe benthos organisms (freshwater)
- Live on, in, or near the bottom of freshwater bodies.
- Includes: molluscs, worms, crustaceans, insect larvae and benthic algae.
Key roles in aquatic ecosystems
- Includes: decomposition of organic matter, nutrient cycling, and serving as food for larger predators.
What is neuston?
Group of organisms that live at the air-water interface of aquatic environments
- including the surface film.
Resting or swimming at the surface
Eg. pond skaters and other insects, and small aquatic plants, which can either float on or just beneath the surface.
What is an epipelic biofilm?
Complex of autotrophs (algae) and heterotrophs (fungi, bacteria, microinvertebrates)
Estuary; what type of organisms would you expect to find in the mudflats and outflow?
Mudflats - epipelic biofilm
Outflow - plankton and nekton
What type of organisms would you expect to find in rivers and streams?
Benthos
What type of organisms would you expect to find in lakes and ponds?
Plankton and nekton
What type of organisms would you expect to find in each of these wetland types; floodplain and permanent?
Floodplain - plankton, nekton
Permanent - benthos
Describe zooplankton features and ecology
Aquatic
Non-motile/weak swimmers - drift with current
Communities respond to many environmental changes
Where are phytoplankton usually found?
Slow-flowing rivers
High light intensity/ temp.
Describe periphyton?
Freshwater organisms attached or clinging to plants and substrate
What does macrophyte mean?
Large plant
What are emergent leaves?
Plant is rooted and has aerial leaves
Leaves sit outside of water
Li, Zheng & Liu (2010) describes what?
Benthic macroinvertebrates
Inhabit bottom substrate
Key components of aquatic food webs
- link organic matter and nutrient resources
What factors affect discharge of rivers?
Precipitation
Catchment geology
Bed slope
Human impacts
Floods
What did (Allan, 1995) find when comparing stony substrate compared to silt - in terms of biodiversity?
Greater range of invertebrates in stonier substrate than pools rich in silt
What are the effects of silt deposition in water? Give citation
Reduces organisms’ habitation
Due to reduced water movement, reduced oxygen levels and food availability
(Allan, 1995)
In what cases of water flow would you find a depositional zone? Give an example
Low water velocity
Net deposition
Amazon River
In what cases of water flow would you find a erosional zone?
High water velocity
Net resuspension
How have human activities affected the hardness of water?
- metal cations and other ions cause hardness (hard water has pH >8.5).
Industrial Discharge: Factories and industrial plants discharge metals into water sources
- Increasing the concentration of calcium, magnesium
Agricultural Runoff: Fertilizers in agriculture can lead to runoff.
- Adds calcium and magnesium to water bodies
K+ (fertilisers)
Na+ (wastewater)
- Do not contribute to water hardness (apparently).
What land-water interchange features reduce pH, human and natural?
Acid mines - rivers which drain acid mines - reduced pH
Mosses - in swamps and peaty areas contribute acidic runoff from catchment (cation exchange)
What effect does increased levels of discharge in rivers have on conductivity and why?
Decreased conductivity
Less dissolved salts and solids
What is allochthonous material?
External material
Leaves fall from deciduous trees, grasses and other terrestrial plants
What is autochthonous material?
Indigenous plant material
Eg. periphyton, plankton, macrophytes
Freshwater; what nutrients are generally available and which are not?
C,H,O generally available
N,P less common
What is nitrogen essential for?
Amino acids (proteins), nucleic acids (DNA & RNA)
What is phosphorus essential for?
Nucleic acids (DNA and RNA), organelle walls (P-lipids), energy molecules (ADP,ATP,NADP)
Describe external loading of nitrogen in freshwater ecosystems
Wastewater disposal (NH4)
Fertiliser application (NO3)
Rainfall, aerial deposition, planting N-fixing crops
Describe external loading (allochthonous) of phosphorus in freshwater ecosystems
Weathering rocks
Human activity - detergent pollution
What is the most abundant form of nitrogen in lakes and streams?
Nitrate (NO3)
Is nitrite (partially reduced NO3) abundant in freshwater systems?
Present in small amounts
What form of nitrogen do plant cells use and in what form is it transferred?
Reduced N
Transferred as amino group - NH2
What type of organism carries out ammonification (NO2/3 -> NH3)
Decomposers
What reaction do denitrifying bacteria carry out?
Denitrification NO3- to N2 (atmospheric)
How does NO3 in lakes and streams end up in fish?
Uptake/photosynthesis into phytoplankton (algae)
Zooplankton
Insect larvae
Fish
What are human impacts on the N-cycle and name a source that discusses this?
Acidification
Eutrophication - Nutrient enrichment
(Erisman et al., 2013)
What process produces dissolved organic phosphate and P04-?
Decomposition
What are sources of phosphorus from landscape?
96% of PO4-P in sewage - city runoff
Agricultural Runoff
Erosion of rocks - weathering, mining
What happens to excess P in water systems?
Stored in algae - later sinks to the bottom of sediment
Describe internal loading of the phosphorus cycle in biota in freshwater systems
Macrophytes - primary producers - large P biomass
Plants transfer PO4 from sediment to water surface
Decomposition - dead organisms releases P
Why is Phosphorus a growth limiting factor in freshwater systems?
- Low concentrations
- P usually limits phytoplankton growth
- No gaseous phase and rain contains little P
- Root zone on land intercepts and retains most soluble P
- Rock breakdown (weathering) releases little
What is the littoral zone (deep lake)?
- Photic
Littoral community
- Edges of water banks
Macrophytes produce energy
- Release some into the benthic zone
What is the Epilimnion? (deep lake)
The uppermost layer in a stratified lake
- Less dense
Characterized by warmer, well-mixed water
- typically oxygen-rich and supports active aquatic life.
What is the Hypolimnion in a deep lake?
The deepest, densest, coldest layer of water in a stratified lake.
- typically low in oxygen and unaffected by wind or solar heating.
This layer remains thermally isolated from the upper layers (epilimnion and metalimnion)
- stores nutrients and sediments.
What community dominates the surface biofilm of deep lakes?
Neuston community
What community dominates the epilimnion of deep lakes?
Phytoplankton dominated
What community dominates the Hypolimnion of deep lakes?
Bacteria dominated
How does the position of zooplankton change throughout a day-night cycle (deep lakes)?
Diel vertical migration (DMV)
Daytime - descend to the aphotic zone
Nighttime - migrate up to photic zone
What is the benthic zone? What functional group inhabits this area?
the ecological region at the lowest level of a body of water such as an ocean, lake, or stream
- heterotropic
- bacteria, protozoa
In what region of deep lakes do nutrients accumulate?
Hypolimnion
What is stratification of deep lakes and describe some of its features? What areas of the world does it occur?
Lake is stratified in different layers
Each layer has a function
Only occurs in temperate regions - not tropical
Retention of warm water at surface
Surface water circulates
What are the implications of lake stratification ?
Implications
- primary production in epilimnion - low inorganic nutrients
- no primary production in hypolimnion, high nutrient abundance
What does holomictic mean? - lakes
During annual cycle, stratification of the lake mix
What does meromictic mean? - lakes
Very deep lakes
During annual cycle there is insufficient energy to overcome stratification - does not completely mix
What does monomictic mean? - lakes
Does not freeze - long mixing period through winter
What does dimictic mean? - lakes
Lake covered with ice in the winter
Mixes twice
- Once in autumn, once in spring
Ice prevents mixing in winter
What does polymictic mean? - lakes
Shallow exposed to wind
Mixes frequently
What does amictic mean? - lakes
Always covered in ice
- no mixing
Describe shallow, unstratified lakes
All in the photic zone
Little distinction between littoral and central zone
- macrophytes in both zones
Too shallow for stratification
- turbulent mixing in summer
Benthic community - light penetration to sediment
- macrophytes (inc. algal mats)
- form autotrophic benthic community
Describe eutrophic lakes
High nutrient input - (N & P)
Shallow lowland lake
Low light penetration - cloudy water
Biota - high primary productivity - high phytoplankton biomass
Found in naturally fertile areas
Describe Oligotrophic lakes
Low nutrient N & P
Deep mountain lake
High light penetration (transparent water)
Found in infertile areas
Biota - low primary/2nd production
- Low biomass overall
Where does mesotrophic fit in lake nutrient status?
Intermediate of Eutrophic and Oligotrophic
Describe the example of nutrient enrichment difference in English lakes and give the citation
(Maberly et al., 2011)
Wastewater (name of lake) - Mountainous lake, infertile area
Deep
Low nutrient status = oligotrophic
Estwaite water (name) - Lowland lake, shallow
Source of water from surrounding cultivated land and human activity
Well developed plankton community
Nutrient rich = Eutrophic
Describe the seasonality of phytoplankton primary production (PP) - lakes
Spring Bloom- Increased PP due to increased solar radiation (heat and light)
Early summer (clear water phase) - low PP (lower than in spring)
- due to nutrient depletion
- increased stratification (reduced mixing from deeper waters)
Automnal - Declining PP
- A secondary peak can occur
if mixing resumes with cooling temperatures (redistributes nutrients)
Winter - low PP due to low light and temp.
What causes the clear water phase in water?
Bloom limited by depleted nutrients at the epilimnion
Leads to a clear water phase (consumed by zooplankton) - low algal biomass
Followed by late summer-autumn bloom
What conditions are phytoplankton adapted to?
Stratification
High temperatures
Low nutrients
Phytoplankton are resistant to _______
Grazing
Zooplankton - only eaten by rotifers and protozoa
How are zooplankton affected by seasonality?
Large peak in spring
Zooplankton consume phytoplankton - leads to clear-water phase
Low numbers in summer due to fish predation and lack of food availability
Can have second peak in autumn following phytoplankton bloom
Describe lake nutrient seasonality
- include lake stratification
Spring
- decrease in N/P (consumed by algal blooms)
Early Summer
- clearwater phase - release of N and P due to cell death and excretion by zooplankton
Late Summer/Autumn
- N uptake by plants exceeds inflow
- decreased N due to increased PP
- input from hypolimnion limited by thermocline
Autumn
- increased N/P due to release by phytoplankton death
Winter
- high N&P inflow
- due to minimal use for Primary Productivity (PP)
- more N&P mixed up from hypolimnion
Describe features of rivers and streams, include the type of animals that live there
Photic zone throughout
Difference between littoral and central zones is small
Allochthonous > autochthonous input
Epibenthic algae; benthic macroinvertebrates; fish
Why are macrophytes and phytoplankton not found in rivers?
High water flow
What organisms does coarse substrate (boulders, stones) attract?
- Benthic macroinvertebrates
Predatory Plecoptera, Trichoptera and grazing Ephemeroptera
What are fish adaptations to running water (other organisms apply same strategy) ?
Streamlined
Flattened ventral surfaces
What do shredders consume?
Leaves ect.
What do grazers consume (rivers and lakes)?
Scrape microbes (biofilm) off solid surfaces
Large allochthonous particles - enter flowing waters - what occurs and what do they provide?
Colonised by bacteria and fungi
- provide essential micronutrients
- broken down by shredders
How and what do organic pollutants in rivers cause?
Increased N & P
Increased organic load > O2 supply needed by decomposer bacteria
Describe the effects of farm water (slurry) on freshwater:
- Nutrients
- Oxygen
- Aquatic life
- Decomposition
- Aesthetic
Nutrients: Increase almost 100%
Oxygen: High Biochemical Oxygen Demand (BOD)
Aquatic life: causes oxygen to be used up rapidly
- Reduced oxygen - Trout and salmon die at low oxygen concentrations.
Decomposition: Anaerobic bacteria (decomposers) produce polluting organic material
Aesthetic: Organic material is reduced into other forms causing a foul smell, severe pollution
What are combined sewage overflows?
Collected runoff from sewage and industrial wastewater in the same system
- serve as storage tank
Prevent backflow into homes during storms
Can cause dramatic decrease in water quality
Describe the physical effects of sewage pollution at site of sewage release - give citation
(Mason, 2002)
High BOD at site of release of sewage
Oxygen levels rapidly decrease - used up by bacteria
Large amounts of suspended solids
Describe the chemical effects of sewage pollution at site of sewage release - give citation
(Mason, 2002)
NH4 spikes - smelly and toxic
- transformed into NO3 - nitrification
PO4 increase
Describe the microorganisms effect on sewage pollution at site of sewage release - give citation
(Mason, 2002)
Sewage fungus blooms - then rapidly decreases as sewage clears
Algal bloom occurs after fungal decline
What are preliminary treatments of wastewater?
Screening/removal of large objects
What is primary treatment of wastewater?
Sedimentation - suspended solids are separated as sludge (as it settles)
What is secondary treatments of wastewater?
Biological treatment
- dissolved organics are consumed in presence of microorganisms
- filter beds or activated sludge provide O2
What is tertiary treatment of wastewater?
Removal of biochemical oxygen demand, bacteria, suspended solids, nutrients
Final disinfection with UV light
What is nutrient stripping and why is it rarely used?
Removes phosphate and other nutrients
- Very expensive
What is done with the sludge produced from the wastewater treatment process?
Some sludge is used as fertiliser
- Some is incinerated
- Some is put in landfill
What is denitrification?
Conversion of NO3 to Nitrogen gas
What does BMWP score represent ?
Value given to water dwelling organisms
Highest value 100
- high score - found in clean water systems
- low - found in highly polluted areas
What are the limitation of BMWP score
Does not take organism abundance into account
When did agriculture begin to spread and what effect did it have?
12000 years ago
Increase in population size - more fire, hunting, land use, overexploitation natural resources
- creates ecological problems
What are examples of disruptions to earth system processes and give the citation
(Rockstrom et al, 2009)
Climate change
Biodiversity loss
Interference with N and P cycle
Ozone depletion
Ocean acidification
When was the holocene?
Last 10,000 years
When and what is the anthropocene?
- the epoch of man
Humans affecting natural cycles
started 1800s? or 1945?
What are supporting ecosystem services?
Nutrient cycling
Soil Formation
Primary Production
What are provisioning ecosystem services?
Food
Freshwater
Wood and Fiber
Fuel
What are regulating ecosystem services?
Climate regulation
Flood regulation
Disease regulation
Water purification
Erosion regulation
What are cultural ecosystem services?
Aesthetic
Spiritual
Educational
Recreational
Withdrawals from rivers and lakes have _______ since 1960
doubled
___% of mangrove area has been lost in last several decades
35
__% of world coral reefs were lost and __% were degraded in the last several decades
20 and 20
Fishing, agriculture, damns, hunting. What do these human activities have in common?
Remove biomass
Remove energy
Alter ability of an ecosystem to cycle energy
What agricultural practices are more efficient (energetically, nutritionally)?
Plant to animal transfer
- only 10% goes toward animal biomass
Agriculture needs to shift away from livestock
Of all species that have gone extinct since 1500AD ___ were affected by overexploitation and agriculture - human driven
75
What effect is globalisation having on species diversity?
Mixing of species from previously distinct areas
Species distribution becoming more homogenous
What percentage of mammal, bird and amphibian species are currently threatened with extinction (medium to high certainty)?
10-30%
What is the largest factor affecting mammal, amphib and bird species today?
Habitat loss
What are two significant factors affecting amphibian species today other than habitat loss?
Pollution and Disease
Why are amphibians so vulnerable to polution?
Very permeable skin
What is an example of a forest type predicted to increase in size in the future and why?
Temperate forest
= conservation effort
What are values of conservation biology?
Diversity of species and communities is good
Extinction is bad
Complexity is good
Diversity has intrinsic value
What are direct uses of biodiversity?
Food
Medicine
Biological control
Recreational harvesting
Ecotourism
Biodiversity is not equally distributed - tropical rainforest cover 7% - what percentage of the world’s terrestrial animals and vascular plant species live there
Give citation
(Greyner et al. 2006)
Over half
What is biogeography?
Analyses distribution of organisms and genetic diversity across space and time of earth’s surface
- spatial distribution
- identifies factors that affect this
Ecological factors - that control distribution
Historical factors - how these patterns developed (evolution and landscape)
What is Wallace’s line?
- Give an example of an animal species that demonstrates this line
In Oceania
Geographic barrier to movement of terrestrial animal species - determined based on taxonomic relationships
Part of sea too deep and wide for animals to cross
Marsupials south east of Wallace’s line are not present on the west side
- Animals diversify in isolation
- Islands have unique terrestrial fauna
Species uniqueness compared to other areas of the world based on phylogenetics - which area has the most unique fauna
Oceania
Why are birds more likely to have more uniform diversity across the world?
Flying - movement not hindered by most geographic boundaries
What does endemic mean? Give an example
Unique to a defined geographical location
Lemurs in Madagascar
What does disjunct mean? - give a couple of examples
Distribution with gaps
Alligators (North America and China)
Araucaria pine (South America and Australasia)
What is N-dimensional hypervolume?
Intersection between all the factors that affect a species ability to survive and reproduce
- fundamental niche
- realised environmental niche
- potential niche
Why are tree frogs much less diverse in the temperate zone than in the tropics
Only a few lineages have adapted to the temperate zone
- the number of species is correlated with time since diversification in that region
Older clades have more species of a group a species have been in a area for an longer period of time
What are historical factors that affect geographical distributions?
Extinction
Dispersal
Vicariance (splitting of a taxon’s range)
Give examples of extinction affecting geographic distributions
Horse family - Equidae
- spread from North America but then became extinct there
- only zebras, Asian horses and Asian wild asses survived
What is an example of how organisms ability to distribute has affected populations?
Example - 1883 Krakatoa eruption - killed all life on island
- 50 years island was covered with forest
- through seed dispersal
Ability to disperse varies
- bats are the only mammal native to New Zealand and Hawaii - due to flight
What are key ecological factors in dispersal of organisms?
Air (wind) - air currents transport seeds, spores, small animals
- prevailing wind currents will carry organisms in certain directions
Ocean currents - seeds, plankton and larvae dispersal
What is vicariance and what does it lead to?
Splitting of a taxons range
- pops. are separated by a barrier as result of geology climate or habitat
No crossing of genes between two populations of the same species
- Leads to divergence and speciation
Explain the distribution of cold adapted species in Europe
Ice sheet formation over northern Europe 10,000 years ago
- formation split species populations
Began to retreat - retreat also split populations
- led to many disjunct populations
What does allochthonous and autochthonous mean in relation to taxa distribution?
Allochthonous - Originated elsewhere
Autochthonous - Evolved within the region
What two continents have good examples of allochthonous taxa?
North/South America
- North American Felines moving South
- other things moving North
Describe tropical rainforest
High rainfall
Low temp. variability
Maybe half the world’s species
Describe Monsoon forest
Low temp variability
Dry season/ Wet season
Mostly deciduous
Describe tropical dry forest
Long dry season
Deciduous trees dominate
Fire sensitive
Describe tropical and subtropical coniferous forests
High altitude
Lower biodiversity than other rainforests
High endemism
What is Latitudinal Biodiversity Gradient (LBG)?
the tendency for more species to occur toward the equator
What is the hypothesis for LBG?
Higher rates of speciation in the tropics (cradle hypothesis)
Less extinction in the tropics
Higher rates of speciation and lower rates of extinction in the tropics - with high species migration out of the tropics
- Last glacial maximum pushed animals away from the north pole
What is the Cradle hypothesis?
Higher rates of speciation in the Tropics
Why?
- warmer, wetter
- more biological interaction - more speciation
Why is there more speciation in the tropics than the temperate regions?
More stable climate
- climate at poles changes - would cause higher extinction rates and migration away from the poles
- explains the gradients of low species numbers nearer the poles
What evidence is there for the different aspects of the LBG hypothesis? Give citation
(Mannion et al. 2014)
Cradle hypothesis - higher origination rates of fossils in the tropics
Ark or Museum - lower extinction rates in fossils in the tropics
Out of the Tropics - trace phylogenetic roots
What LBG relationship was seen in the dinosaurs?
no relationship between diversity and latitude gradient
When was the Pleistocene and what was a consequence of it?
1.8 million years ago to 10,000 years ago
Many northern species ocurred far to the south of there present distribution due migration caused by glacial periods
Why are microsatellites used in Molecular Ecology?
High mutation rate makes them informative for detecting more recent events
What is mtDNA?
Small circular chromosome found inside mitochondria - encodes genes for energy production
What are the advantages of mtDNA as a tool in molecular ecology?
Maternally inherited
No recombination - allows direct sequencing of haplotypes
Multiple copies - easy to amplify
Higher mutation rate so more variation (information)
What is a disadvantage of mtDNA as a tool in molecular ecology?
Genetic introgression between closely related species
Example - Neanderthal human integration
- Hard to establish what came from where
What is a haplotype?
Physical grouping of genetic information along a chromosome (tend to be inherited together)
What are examples of invasive tissue collection methods?
- Toe clipping - amphibians
- Ear clips
- Blood.
- Wing punches (bats)
What are examples of non-invasive tissue collection methods?
Buccal swabs
Faecal Samples
Hair traps
General walk through of PCR components
DNA Sample
Primers
Nucleotides
Taq polymerase
Mix buffer
Describe the PCR cycle - temperatures and stages
Denature template - >90C
Anneal primers - ~55C
DNA synthesis - >65C
In what locations and species are biodiversity numbers often not known?
Tropics
Small taxa - insects
Why would high level cryptic species be a problem for species count and what method is used to combat this?
Species that are distinct but morphologically indistinguishable
Molecular tools - DNA barcoding
Which type of organism has the least discovered species in Southeast Asia? - Highest rate of deforestation (in world?)
Legumes - many will go extinct before they are discovered
What is DNA barcoding?
Uses short DNA sequences
- mitochondrial cytochrome c oxidase (CO1) gene (in animals)
- this gene region has sufficient mutational differences to differentiate species
DNA barcoding - why don’t plants use the same mitochondrial region as used for animals?
mtDNA is far less variable in plants
- 2 chloroplast genes are used instead
What is the difference between inter/intraspecific variation?
- Intraspecific variation (“within species’’ variation), or variation among individuals of the same species.
- Interspecific variation (“across species” variation) is variation that occurs when comparing individuals of differing species
What are limitations of DNA barcoding? - give citation
(Collins and Cruickshank, 2013)
- Overlap between interspecific and intraspecific genetic variation
- Mitochondrial introgression
- Variable mutation rates
- High divergence can accumulate quickly in bottlenecked population
What does overlap of intraspecific and interspecific variation in DNA barcoding suggest about two species?
Likely the same species
Give an example of DNA barcoding in use
Ants in madagascar - revealed higher levels of biodiversity than standard morphological methods
Birds in philippines - Large numbers of cryptic species
What is phylogeography?
The processes of dispersal of organisms that carry the genes
Phylogeography provides insights into past movements of species and how they attained their present distributions
What effect did the glacial maximums of the Pliocene and Pleistocene have on animal distributions?
Temperate adapted species moved to glacial refugia (is a geographic region which made possible the survival of flora and fauna in times of ice ages)
What do the distribution of species in northern and central Europe tell us about Glacial refugia species and their movement? - give example
Haplotypes in northern and central Europe - most closely related to those found in the Balkans
- Grasshopper from the Balkans
Conclusion - Many animals did not cross the mountains (pyrenees from Iberia or the Alps from Italy)
What is a suture zone and give an example of this occurring?
Suture (hybrid) zone - area of mixing refugia populations of previously allopatrically separated populations
Example
- Hedgehogs - some species were able to cross the Pyrenees and Alps
- mixing separate groups
What are some consequences of the periodic glaciations in northern latitudes?
Several refugia in Europe
Greater diversity genetic diversity in the South than the North
Northern biotas made up of different refugia
What are some consequences of the periodic glaciations in the tropics?
Climate colder and dryer
Contracted and fragmented tropical forests
What is the Rainforest refugia hypothesis? Give citation
(Haffer, 1969)
During pleistocene glacial periods rain forest was fragmented into several fragments - refugia
Allopatric fragmentation of species
- creates genetic divergence and speciation
Hypothesis has been rejected for Amazonia
- APPLICABLE for Africa and Southeast Asia
How does the Okapi in central Africa back up the Rainforest Refugia Hypothesis?
Forest dependant animal
Phylogeography of the Okapi - mtDNA variation shows distinctive lineages - consistent with repeated Plio/Pleistocene forest refugia
Pleistocene environmental changes in Southeast Asia likely affected organism distribution. Describe the differences between interglacial and glacial periods
- Sea level
- Precipitation
- Aridity
- Forest
During interglacial periods
- High sea levels
- High precipitation
- Decreased aridity
- Spread of tropical forest across mainland and islands
During Glacial periods
- Low sea levels
- Reduced precipitation
- Increased aridity
- Tropical forests replaced by grassland
What is an umbrella species?
Large-bodied and wide ranging animals
- Require large area of suitable habitat
- Conservation of these species conserves whole ecosystems
Eg. Tiger and Pandas
What is a sentinel/indicator species?
Species whose ecology and sensitivity to environmental changes are well know
Eg. Amphibians, lichen
What are Keystone species? Give an example
A species that plays a disproportionately large role in supporting the ecosystem
Otters maintain kelp ecosystems by consuming sea urchins - which destroy kelp forests
Black-tailed prairie dogs are a _____ species. What do they do?
Keystone
- Prey for many animals
- They burrow
- Provide habitats for plants which attracts grazers
- Provide homes for other species
The biomass they effect/provide far outweighs their own biomass
What is an ecoregion?
Share large majority of species
Similar environmental conditions
Interact ecologically - critical for long-term persistence
What are Evolutionary Significant Units ESUs?
Group of population with common evolutionary history
Conserving multiple ESUs maximises the conservation of evolutionary history
What are Management Units MUs?
Units of a population
Results of more recent isolation
Differ in allele frequency due to lack of gene flow
What factors did Norman Myers use to identify the 25 Biodiversity hotspots?
High endemism
Contain at least 0.5% endemic vascular plants
- Suggested these as conservation focus areas
What are tropical wilderness areas?
High endemism and pristine - should be high priority for conservation
What are the Global 200?
WWF identified 200 priority ecoregions
High biodiversity (species richness and endemism)
Conservation of these ecoregions would save most of the diversity of the Earth’s Ecosystems
What is the “Global Deal for Nature”?
Advocated by Dinerstein & Olson et al (2017)
Ecoregion based approach to protect and interconnected 50% of the terrestrial realm by 2030
What is the approach suggested by the Convention on Biological Diversity (CBD)?
- Ecosystem approach to conservation
- Integrated management of land, water and living resources - promoting conservation and sustainable use
- recognizes humans as integral component of ecosystems
What % of land is moderately to highly degraded and why?
33%
Due to human activity
Why is 25-40 billion tons of topsoil lost every year to erosion?
Largely due to land management
What is the role of microbial biomass in the soil food web?
Primary consumers
- break down complex organic material
- nutrient transformation
- structural stability
- symbiotic relationships (mycorrhizal; N fixation)
What is the mycorrhizal fungi relationship with plants?
Symbiosis - Mutual relationship
Fungi give nitrogen and phosphorus
Plants supply carbon
What enzyme do microbial nitrogen fixers use to carry out their function?
Use nitrogenase to catalyse conversion of atmospheric N2 to ammonia (NH4)
Describe nematodes
- What order
Microfauna
Soil fauna - secondary and higher order consumers
What are soil dwelling protozoa (protists)? Describe their movement and functional groups.
Microfauna
Single celled eukaryotes
Soil movement via soil solution
- movement restricted by pore size
Photoautotrophs - primary producers (algae)
Heterotrophs (protozoa) - feed on bacteria and fungi
What are mesofauna of soil?
Enchytraeid worms
Microarthropods (mites/collembolans)
- most fungal feeders
What mesofauna dominates acidic peat soils and in what forest/zones are they a keystone species ?
Enchytraeid worms
- keystone species of boreal and tundra zone
What type of soil fauna are earthworms considered to be and what are they sensitive to?
Macrofauna
Intolerant to acidity - replaced by enchytraeid worms
What abiotic factors affect the distribution of soil organisms?
Soil porosity - pore sizes
- determine movement of water and biota
Soil water
- water films represent habitat
Soil temperature
- rate enzyme reaction
- temp. tolerances
Soil pH
- pH tolerances vary greatly
What is the rhizosphere effect?
Microorganisms more abundant around roots
- Roots provide compounds (rhizodeposition - amino acids and sugars) which microorganisms feed on
- stimulates microbial abundance and their predators
What limits microbes in a rhizosphere?
Carbon
Describe the relationship of deciduous forest and its soil
Deciduous forest
- High litter Nitrogen
- Low lignin and phenolics
Fertile neutral pH soils
- high abundance of bacteria and bacterial-feeding predators and earthworms
High rate of decomposition (nutrient turnover)
Describe the relationship of coniferous forest and its soil
- Litter
- Nutrients
- Soil
- Organisms
- Decomposition Rate
Low litter N
High phenolics
Infertile acidic soils - absence of earthworms
High abundance of enchytraeids
Slow decomposition (low nutrient turnover)
Is there faster nutrient cycling inside or outside area of tree influence?
Outside
- Inorganic nutrients - high NO3
- High bacterial biomass
Inside sphere
Organic nutrients
- High fungal biomass
- Low microbial biomass
Give the citation and describe the effects of intensive agriculture on soil biodiversity
(Tsiafouli et al., 2015)
Gradient of soil management intensity
- intensive agriculture affects soil quality and nutrient levels
- higher intensity lower soil quality
- higher intensity lower biodiversity
What is the relationship between aridity/temp. and microbial diversity found by Maestre et al (2015)?
Dryer warmer ecosystems - less diversity
- dryland expected to keep increasing in size
What did Finlay (2002) find about microbial species distribution?
As they are so small there is no limit to their distribution - move with wind, bugs and plant material
Distribution in the field mirrors the distribution around the world
As their dispersal is not limiting
What did Finlay (2002) find about microbial species distribution?
As they are so small there is no limit to their distribution - move with wind, bugs and plant material
Distribution in the field mirrors the distribution around the world
As their dispersal is not limiting
Why does the trend in soil animal diversity not match the trend in microbial soil diversity?
Animals inability to disperse as efficiently
How much have humans increased species extinction rates?
1000 times over background rates
10-30% of mammal, bird and amphibian species are threatened with extinction
What did (Cardinale et al., 2012) find about diversity and ecosystem productivity?
More diverse communities - more productive ecosystems
What is causing the decline of soil diversity (soil families)?
Overcultivation and construction
What is the top threat to soil diversity and soil biota biodiversity?
Intensive agriculture
What were key finding of (Tsiafouli et al. 2015) - soil and land usage
Increasing land use intensity decreases diversity within soil functional groups and avg. no. of trophic levels
Reduction of diversity decrease biomass of macrofauna
Some cases functional groups entirely missing - slow to recover
What is the redundancy hypothesis?
High level functional redundancy within communities (niche overlap)
As long as biomass and main trophic groups maintained
- So many species that losing some doesn’t matter as another species will fill the niche
Studies have backed this up (very artificial)
- Did show if there was to much loss then the system will eventually collapse
What is the rivot hypothesis?
All species have a role (linear)
- Linear relationship between diversity and function
- If to many species of lost eventually the ecosystem will crash
What is the idiosyncratic hypothesis?
High functional redundancy, some species more redundant than others
- Keystone species - certain species (usually larger as there is less niche overlap) are more important to the ecosystem - if lost the ecosystem could crash
What is an engineer species?
Influence ecosystem process through physical disturbance
Eg. moles & earthworms burrowing holes
- used by other organisms and water
- shape environment
What is the insurance hypothesis?
Diverse communities are more likely to contain species that can withstand environmental change
What were the effects found by a study creating a soil biodiversity gradient - using finer and finer sieves to decrease numbers of AM fungi species?
Finer sieves
Nutrient cycling reduced
Phosphorus leaching increased (loss of phosphorus)
- Negative effects of reduced biodiversity
Species loss does affect soil function
What grade will hoop get on his ecology exam?
Probably zero - gonna be late
Experiments carried out in the field on microbial diversity in soil
- Showed a steep decline in functionality when to many species were lost
What hypothesis does it support?
Rivot hypothesis
Describe capture-mark-recapture (CMR)
Several sampling sessions
Record each time an a individual is caught - determine new individuals at each time point
Define biogeography
The distribution of organisms (and genetic diversity) across the surface of the earth in space (and time)
What are the 2 main considerations in conservation?
Where to put the protected area?
Will the diversity be maintained?
- will its function be maintained? (Water/nutrient cycling)
Island Biogeography - Describe the relationship between species no. and distance from mainland
Number of species decreases with distance from mainland (-linear)
Island Biogeography - Describe the relationship between species no. and island area
No. of species increases as size of island increases (linear)
Target effect. How might island size affect colonization rates?
Larger islands - higher colonization rate
- larger target
- more seeds arrive
Rescue effect. How might island nearness to mainland affect extinction rates?
Decreased extinction rates
Rescue - population replenished from mainland
- New genetic diversity
- New individuals
Describe some feature of a well designed reserve
Large
Intact rather than fragmented
Several rather than few (more protected from disease and natural disaster)
Connected reserves (wildlife bridges)
Diverse ecosystems
Fully protected - eg. with a river if dumping is occurring upstream - defeats purpose
Round better than thin - edge effects
Describe species-area relationships to extinction in reserves
Extinction rates decrease with increasing protected area
Why are larger protected areas beneficial to survival rates of an animals in these areas?
Fewer ‘edge effects’
Larger populations supported
More species
Larger species less likely to go extinct in larger reserves
Wider range of habitats
Less susceptible to natural or anthropogenic disturbance
Why is larger size of reserve beneficial to survival rates in protected areas?
Fewer ‘edge effects’
Larger populations supported
Larger species less likely to go extinct in larger reserves
Wider range of habitats
Less susceptible to natural or anthropogenic disturbance
Describe the edge effect - features of the periphery area?
Give citation for edge effects
(Broadbent et al., 2008)
Lower habitat quality
Invasions of exotic edge species
Different microclimate
Avoidance by ‘interior’ species
Larger reserves have more core habitat - pieRsquared
Why is it important to have multiple reserves?
Environmental catastrophes - human and environment
Don’t want eggs all in one basket silly
Describe the SLOSS debate
Single Large Or Several Small
Edge effects - single better
Catastrophic events - several better (eg. more likely to avoid spread of fire to all areas)
Ease of movement between reserves - harder movement between reserves is
- the stronger the argument for single reserves is
Describe buffer zones around protected areas
Low-impact buffer zones around protected areas such as multi-use zone (human and wild) or farmland rather than cities
Consideration when designing the matrix (connections between reserves)?
Can the species move through it
How safe is the matrix - eg. roads, cars?
What is a meta-population?
Individuals in separate reserves moving between one another - managed as one
What are the benefits of habitat corridors
Mitigate effects of habitat fragmentation
- Increased recolonisation potential
- Increased gene flow
- Providing additional habitat
- Increased individual survival
Why is creating habitat corridors difficult?
Animals are unlikely to listen to us if we plant trees up or put a fence up
- They don’t understand us
Behaviours are difficult to change - migration/movement patterns
- even when an obstacle has been removed - animals often continue to ‘ghost gaps’ (where fence used to be)
Do protected areas work?
More money more ability to protect - enforcement, boundary demarcation
- Generally successful at stopping land clearing
- Also reduce logging, hunting, fire and grazing
Describe Conservation by the Exclusion of People
Restricted access to protected areas
In the tropics - colonial and post-colonial governments removed people from areas they inhabited to protect the areas
Often infringed on right of local people
Although in many cases it has had a positive effect on biodiversity - reducing deforestation
Now moving toward community based conservation - involving local people
What is the ‘noble savage’?
Conversation of returning indigenous land rights
Assumption that natives would not negatively affect the environment as they are one with nature (primitive) - racist
Enforcement vs provision of livelihoods as poaching prevention methods
Law enforcement - social cost
Shoot to kill policies - controversial
Providing economic incentives and employing local people as wardens - more effective (some proof)
What is a gap species?
Species whose range falls outside protected areas
What is the conservation challenge with migratory species?
May not be protected in some parts of their range
Difficult coordinating conservation efforts between countries
What is are some methods to help coexistence between wildlife and humans?
Shock collars on predators
Guard dogs
Support bee populations near crops
What is the tipping point in human-modified landscapes for forest biodiversity conservation?
Delivery of goods and services from forest hits optimal at moderately managed landscape
- Eventually there’s no more goodness that can be gotten out without significant damage to the forest
- Forest loss, high intensity agriculture, human settlement
- Begin decreasing these services
Designing optimal human-modified landscapes - when does it stop being beneficial to protect an area further in relation to species richness and biodiversity
- Optimal preservation of forests - stops benefitting species richness after a while
- Benefits of further protection become less valuable to supporting biodiversity
- Eventually there’s no more goodness that can be gotten out
Describe the site of exchange of arbuscular mycorrhizal fungi and plants
AM fungi have highly branched arbuscule (site of exchange) within root cortical cells (penetrate plant root)
Which do AM fungi benefit more; dominant species (grasses) or sub-dominant (herbs) in a community with both?
Sub-dominant
- decrease dominant in a community that includes sub-dominant species
What mechanisms of AM fungi are thought to cause the differences in the interactions between dominant and sub-dominant plant species (such as herbs)?
C donor hypothesis - Am hyphal networks interconnect species carbon and nutrient supplies between herb species
- stronger together typa thing
Increase survivorship of sown herbs
Increase establishment of herbs
What was the relationship found between AM fungal diversity and plant biomass (PP) found in Mesocosm experiments?
Higher Am fungi diversity
- Higher plant biomass (plant productivity)
What were the conclusions made from the mesocosm experiments? What does greater abundance of fungi and longer hyphal growth produce?
Different hyphal growth forms and lengths
More efficient soil phosphorus exploitation
More plant biomass and diversity
AM FUNGAL DIVERSITY PROMOTES ECOSYSTEM FUNCTIONING
Explain the development of Marram grass and root pathogens
Sand dunes
- Marram grass dominates youngest dunes
- Begins to degenerate quickly declines
- Replaced by other plant species
- Caused by plant specific pathogens (builds up in the dunes)
- Parasitic nematodes and soil-borne fungi
- After death other plants are able to live without the effects of the plant pathogen
Why is crop rotation used?
Build up host specific parasites/parasites
AS IT grows it accumulated pathogens that lead to its demise
Over multiple seasons of crop planting pathogen levels become very high
Explain the mechanism for why rare plants are rare?
Rare plants - exhibit negative feedback limiting their growth and spread
- accumulate plant specific pathogens - limit growth
- grow better in soil of other plants
What is the hypothesis for why highly invasive plants are highly invasive?
Accumulate pathogens slowly
Display positive feedback
- modify soil biota in a way that promotes their growth
Describe Rhinanthus minor
Facultative root hemiparasite plant
- attaches to roots of fast growing plants as prefered host
- extracts nutrients from host
- allows survival in low nutrient environments
- reducing their competitive dominance of fast growing plants
- reduces field fertility
What is the mechanism of R. minor in soil?
Infects dominant plant roots
Causes root death and increased leakage of carbon into soil - stimulates microbes
Enhanced N cycling and plant N supply
Parasite driven enhancement of microbial N cycling in soil
How do infertile forest soils (N limited) sustain high levels of tree productivity? - little inorganic Nitrogen
How do pine trees control soil N availability to benefit their growth and competitive ability in N limited ecosystems ?
Polyphenol (tannic acid - tannins) - production from pine litter
- inhibits N mineralisation and availability inorganic N
Pine litter decomposition release amino acids, peptides and proteins (DON)
- microorganisms break these down further
- trees use them through mycorrhizal fungi
CONFERS COMPETITIVE ADVANTAGE
What is a key limiting factor in infertile forest soils?
N-limited
Microbial mineralisation of organic nitrogen to plant available inorganic nitrogen (nitrate to ammonium)
- control on plant N supply
What is the trend of inorganic N in infertile forest soil with increasing DON
Decreasing inorganic N (ammonium, nitrate)
How can slow-growing, phenolic rich herb (Acomastylis) and fast-growing grass coexist in alpine meadows?
- usually fast growing outcompetes slow growing
Phenolic rich litter produced by herb
Reduced microbial uptake of N and N availability
Reduced growth of fast growing dominant grasses
ACOMASTYLIS modifies environment to enhance its persistence
Why is there a varying range of plant biomass consumption rates across ecosystems?
Wide variation due to plant structures
- Herbivores struggle to eat wood
What are the negative impacts of herbivores on soil biota and ecosystems?
Selective grazing and reduced quality of litter inputs
- select favoured plant species
- leads to dominance of species they find undesirable (often with reduced litter quality)
What are the positive impacts of herbivores on soil biota and ecosystems?
Retardation of succession and faecal return (short-cut litter decomposition)
What herbivore behaviour causes deceleration and how?
Selective grazing at low densities favours defended, low tissue N plants (low fertility forests)
- Low grazing pressure
- Plant production is not consumed by herbivores
- Herbivores consume non-defended plants
- High tannin polyphenol litter increases
- Nutrient availability is reduced
- Negative feedback that slows nutrient cycling
- Low soil nutrients favour growth of slow growing conifer trees - negative feedback loop
What herbivore behaviour causes acceleration and how?
Positive feedback loop in fertile sites
- herbivores favour tolerant plants - high tissue N
- high soil fertility and consumption of NPP
High grazing densities
- graze tolerant plants become dominant
- nitrogen rich tissue
- stimulate nutrient cycling
- increased herbivore support
What occurred on Isle Royle in lake superior when the moose was reintroduced?
Browse in boreal forest
- selective grazing on hardwood led to dominance of conifers
- reduced tree production
- produced litter high in polyphenols (tannins) low N
- reduced microbial activity and N mineralization
- ecosystem productivity reduced
Carry capacity reduces
- Moose population collapses
What are the effects of red deer browsing? - why they are culled in scotland
Reduced tree regeneration
Decreased N mineralization
- 4 fold decrease in grazed compared to ungrazed
How do red deer (grazers) reduce ecosystem functioning?
Tree growth increase biological activity
- grazers suppress trees
- reduced ecosystem productivity
Describe the effects of sheep grazing in fertile temperate grasslands - what is the mechanism?
Increased microbial biomass
Increased N mineralization
Increased plant N
Increased NPP
Dung shortcuts litter decomposition
Stimulates biological activity
Describe the effect of grazers in the Serengeti and what is the reason for this behaviour?
Grazers preferentially forage mineral rich plants (higher nutrient availability)
- beneficial for late stage pregnancy, lactation and offspring growth
- animal activities augment nutrient availability
Serengeti; What were the effects on annual net N mineralization and Soil Na stocks (reproduction) when grazers were concentrated in an area? -what does this cause
Increased
- grazed plants had increased transpiration
- Causes Na accumulation in surface soil
- increased biological activity
- increased carrying capacity
African grazers modify ecosystem processes to increase nutrient availability - increasing carrying capacity
Describe the disturbance effects of grizzly bear in alpine meadows
Grizzly bears forage by digging for bulbs
Digging - increased nutrient content and seed production of glacial lilies
These digs cause more inorganic N to be present in the soil
Lily bulbs have higher levels of N and carbohydrate content
- provide better food source to the bear
Why is overgrazing such a problem?
Overwhelm natural processes
- less productivity
- grassland degradation
- millions of people rely directly on grassland productivity (especially affected in developing countries)
What is the global on-farm cost of grassland degradation?
$6.8 Billion
Why are grasslands resistant to grazers?
Grow from the base up
- Grazing does not kill the grass
Co-evolved
Why does grassland biodiversity not increase with area increase (unlike tropical rainforests)?
Relatively uniform
What is behavioral ecology?
Study behaviour and how it allows animals to adapt to their environment
What are Tinbergen’s Why’s?
Example - Why do starlings sing in the spring?
Survival value or function - Attract mates
Causation - (physiology) increasing day length has altered hormone levels; (anatomy) air flowing through syrinx
Developmental - the starlings have learnt their songs from their neighbours
Evolutionary History - certain songs are more successful - increasing reproductive success - natural selection
How did altruism evolve even though it would seem to reduce an individual’s fitness?
Selfish behaviours should be more common
But some altruistic behaviours have personal benefits in social context
Kin selection
- Brothers/sisters share genes with your kin
- Traits that protect kin improve inclusive fitness and so can be selected for
Reciprocal altruism
- food sharing - in time of need individuals return the favour
Give an example of social animals relying on kin selection to increase inclusive fitness?
Bees dying when they sting
- Protecting offspring increases their inclusive fitness even if they die
Give the example of selfish behaviour shown by the male Hanuman langurs and why it occurs?
Infanticide
- Acts aggressively toward the young of another male (may kill them)
- Reduces time for female to become fertile
- as infants rely on mothers food (milk)
- male may father their own offspring sooner
What is hamilton’s rule? Describe what each term means
Closer the relationship between kin the more beneficial and so more likely the altruistic act is
rB > C
- r is the genetic relatedness to the actor
- B is the reproductive benefit gained by recipient
- C is the reproductive cost to the actor
Describe how the bright stripes of the Datana caterpillars which advertise their bad taste are an example of kin selection.
All larvae in a group are likely to be related (from one egg mass)
- death of one caterpillar teaches the predator to avoid the pattern
- Protecting the caterpillars close kin
What is alarm calling an example of?
Altruistic behaviour
- Warns others of predators
- usually closely related individuals
- Draws attention to itself
When is reciprocal altruism possible and give an example of an animal that does this
Social groups where animals can remember an individual that did a good deed in the past
- And there is an opportunity to return the favour
Female vampire bats will regurgitate food to unrelated female if needed
- Helps them survive
- Dramatically increases time until female bat will starve to death but does not decreases the time the donor has until starvation that much
What are the costs of group living?
Competition for resources within group (space, food, mates)
Increased levels of disease and parasites
Higher visibility to predators
What are the benefits of group living?
Territory defence so better access to resources between groups
Anti-predator strategies; defence, vigilance, dilution effects
Cooperation and food sharing
Shared parenting (Alloparenting)
Information sharing
What is alloparenting?
Parenting carried out by individuals not directly related to children
What are benefits of being centre of the herd and what is this theory called? And what are the benefits of being on the outskirts?
Centre (Selfish Herd) - better protection
Outskirts - better access to food
The optimal group size for killer whale hunting is 3, why is the stable group size 5?
In groups of 5, the payoff to the group is still larger than when hunting solo even though it is far less than when hunting in groups of 3
- leaving the group would have a negative impact on the individuals fitness
- although at 6 killer whales the benefit of group hunting drops below the payoff of hunting solo
Describe what (Zach, 1979) found when studying crows feeding on whelks
Choose larger individuals - break more easily
Fly 5m up and drop them to break their shells
Why this height? - most energetically efficient, reduces the chance of need of repeats while also not needed to fly to high
- cost of flying needs to be outweighed by the benefits of the food
What is the leaf cutter ant strategy to avoid parasitoid wasps?
Larger individuals forage at night to avoid the wasps as they can only parasitise ants of a certain size
Give the citation for the Hawks and Doves theory for territory defence?
Maynard Smith (1976, 1982)
What is the strategy of the Bourgeois in the Hawk Dove Bourgeouis model?
Acts as a hawk if they are defending territory and a dove if they are intruding
Why is the Bourgeois the only evolutionarily stable strategy in the Hawk Dove Bourgeois model?
Cannot be invaded by others
- Would find itself in control of territory half the time
Mean payoff is stable
Why are the sex ratios almost 1:1 even though generally not as many males are needed in a population? and who found this?
(Fisher, 1930)
This is an evolutionarily stable strategy
If a population has more females than males then it is beneficial to have more males until the population drops back to 1:1
Sorry these make no sense to me either not really sure why i bothered making these game theory flashcards complete waffle
What are the four different mating strategies?
Polygyny - multiple females per male
Promiscuity
Monogamy
Polyandry - multiple males per female
Describe potential reasons for promiscuous mating and give an example
Chimpanzees and bonobos
Sometimes occurs when the risk of not finding a mate is high
Could be linked to social cohesion and complex interaction but promiscuity is very uncommon in primates
Why is sex in promiscuous primates thought not to be purely for reproduction?
Mating - not only for reproduction
Often male - male
or female - female
Can even be close family so definitely not for reproduction
Describe the potential reasons for monogamous mating?
May be related to mate guarding - in males interest to guarantee the offspring are his
Male-assistance monogamy hypothesis
Female-enforced monogamy hypothesis
Describe monogamous mating
Individuals mate exclusively over at least one breeding season
What is the male-assistance monogamy hypothesis?
Monogamy is prefered when male help at the nest has a large impact on offspring survivorship
- Most common explanation in birds
What is the female-enforced monogamy hypothesis?
Female’s interest to ensure male assistance and that she will enforce it
Why is monogamy rare in mammals?
In terms of fitness it is strongly in the males interest to mate with as many females as possible and to defend them
What is resource based polygyny and give an example
Occurs when there is a resource that a male can dominate
Lark bunting nests in grassland where shade is key to nesting survival
- Male territory is shaded area
- Has control over multiple females
What is a harem mating structure and how long are males dominant for?
Occur when a male defends a group of females without a specific territory
Common in social animals where females naturally group together
Short periods of time males are dominant for
- many males are never dominant
What mating structure is commonly linked to infanticide?
Harem mating structure (polygynous)
What is communal courting (leks) and what is it an example of?
2 or more males perform elaborate courtship displays and females choose the best - gene shopping
- Runaway sexual selection
Jacanas (tropical bird) has a polyandrous mating system, why?
Egg predation is common
- Males build nests (will continue to defend)
- Females compete to lay eggs in multiple nest
What are examples of polyandrous mating animals?
Jacanas (tropical bird)
Kalahari meerkats (fight for rank)
Spotted hyenas (fight for rank)
What is intersexual selection?
One sex (usually females) chooses mates based on an attractive feature
What is intrasexual selection?
Members of one sex (usually males) compete over partners with the winner performing most of the matings
What are nuptial gifts and what type of sexual selection is it an example of?
May help female fitness directly, or may indicate male fitness
Intersexual selection
What is runaway sexual selection?
Some ornamentation is very impractical
- but is selected for as it is favoured by females (or mate not doing display)
What are adaptations created by intrasexual selection and why?
For fighting
- Large body size
- Weaponry (horns, canines)
Why are honest displays of strength before battle key in intrasexual selection?
Only worth fighting if individuals are relatively similar and the result isn’t inevitable
What are examples of sexual dimorphism in primates?
Male:female body size
Male:female relative canine size
In what type of relationship is relative testis size largest?
Promiscuous - Multiple males mating with each female
bigger balls = higher fitness
In what type of relationship is relative testis size smallest?
Polygyny
- no need for big balls
- no competition during reproduction
Which type of relationship has the smallest male:female body size dimorphism and canine dimorphism?
Monogamous
- Not continually competing with other males
Describe what age distribution you’d expect to find in an undisturbed forest compared to an overgrazed forest and why?
Undisturbed
- More younger trees
- Outcompete older trees
Overgrazed
- Distribution leaning toward older trees
- Overgrazing reduces abundance of young trees
What is survivorship = ?
Survivorship = number surviving this year / total number born
Age-specific mortality =
Age-specific mortality = number dying / number dying
Oops done something wrong here
What is a type 1 survivorship curve?
Low death rate at birth
Increases dramatically later in life
Eg. humans
What is a type 2 survivorship curve?
Linear increase in death rate
Eg. seeds in a seed bank
What is a type 3 survivorship curve?
High mortality rate at birth
- once developed mortality rate decreases dramatically
Describe the general features of a type 1 organism?
Few offspring - invest a lot into them
- parental care as individual offspring are valuable
Describe the general features of a type 3 organism? and give an example
Large number of offspring
- little investment
Eg. plants (lots of small seeds and few germinate)
What are the survivorship curves seen in ungrazed and grazed grass?
Ungrazed - type 1
Grazed - Initial die off due to preferential grazing of younger grasses and then development into type 1 curve
What is an organism’s life history?
Describes timing of key activities
- Age of death
- Age of maturity
- Interbirth interval
- Generation time
Also include population metrics - litter size
What would likely cause a geometric growth pattern in a population?
Seasonal breeders - reintroduction (into empty niche) of a population into a habitat
What population growth curve would you expect to find from a reintroduced continually breeding population?
Exponential growth curve
- If resources were unlimited it could go on indefinitely
How do humans manipulate the carrying capacity of certain species in farming?
Pesticides and fertilizers increase K - Carry capacity
What type of animal is most affected by space limitation?
Small mammals and birds (nesting)
What type of animal is most affected by predators, parasites and disease?
Insects
What type of animal is most affected by food availability?
Large mammals
Although also has large effect on small mammals, insects and birds
What are some density dependant factors that affect population growth?
Limited space/overcrowding
Limited food supply
Predators
Parasites and disease
Why is there sometimes a lag in the time for density dependant limiters on population to set in?
Rates of disease, parasitism and predation lag behind population growth
What pattern does a K-limiter produce in animal density (population size)?
Causes oscillation
- When the lag catches up it causes the population to crash
- the population then recovers and the cycle repeats
What is the trend in animal population density for non lagging k-limiting factors?
No oscillations - straight line
How can lagging K-limiters cause extinction?
If the crash is to large the population can be wiped out
What is semelparity? Give an example
Breeds once in its lifetime then die
Salmon
Give an example of an iteroparous -seasonal breeder
Birds
What is an iteroparous species?
Give an example
Breed whenever (all year) or seasonal
- multiple in a lifetime
Chimpanzees - all year round
What is an R-selected species
High growth rate per capita
What is a k-selected species?
Stable populations that exist close to the carrying capacity
Describe features of an r-selected species
Development -
Reproductive rate -
reproductive age -
Body size -
Lifespan -
Competitive ability -
Survivorship curve -
Population size -
Dispersal -
Habitat type -
Development - rapid
Reproductive rate - high
reproductive age - early
Body size - small
Lifespan - short
Competitive ability - low
Survivorship - Type 3
Population size - variable
Dispersal - good
Habitat type - disturbed
Give examples of r-selected species
Weedy plants, small fish, insects, bacteria
Give examples of k-selected species
Canopy trees, large mammals
Describe features of an k-selected species
Development -
Reproductive rate -
reproductive age -
Body size -
Lifespan -
Competitive ability -
Survivorship -
Population size -
Dispersal -
Habitat type -
Development - slow
Reproductive rate - low
Reproductive age - late
Body size - large
Lifespan - long
Competitive ability - high
Survivorship - Type 1
Population size - fairly constant
Dispersal - poor
Habitat type - not disturbed
What proxy can be used to measure age of elephants?
height
- measured with laser range finding
What are the four potential consequences of the Lokta-Volterra competition equations? Competition between 2 species
Species 1 eliminated
Species 2 eliminated
Either is eliminated
Co-existence
How does coexistence occur rather than competitive exclusion?
Give the 5 species of wabler as an example
Niche differentiation - resource partitioning
With competitive exclusion there should only be one species
- each wabler species prefers to feed at a different height and portion of the tree
- reducing competition
Why does evolution removes niche overlap?
Less competition for resources
- increase individual fitness
Species pushed to exploit resources at the edge of their niche
Leads to adaptation - character displacement
What are some predation defences?
Chemical and aposematic colouration
Cryptic colouration
Batesian mimicry - palatable
Mullerian mimicry - unpalatable
Physical defences
Intimidation displays
Predator satiation
What is aposematic colouration and give an example
Colour advertises poisonous nature
Blue poison arrow frog
What is cryptic colouration? Example
Camouflage
- Indian leaf butterfly - disguised as leaf
What is Batesian Mimicry?
Non-poisonous animal mimics poisonous animal to scare predators
What is Mullerian mimicry?
Toxic animals (prey) mimicking each other
Why do zebras have stripes?
Moving stripes may dazzle predators - dazzle predators when moving - hard to single out individual from herd
Social - Stripe patterns are individual so they may be used to identify
Fitness indication for mate identification - irregularities may indicate disease, injury
Thermoregulation
Protection from tsetse flies - flies seem least attracted to striped horses
Why are rare species more likely to go extinct?
Rare species - small disturbances can cause extinction due to low numbers
Why are species with poor dispersal ability more likely to go extinct?
Poor dispersal ability - inability to reach new areas - if habitat is destroyed they will likely die with it
Why are species with high degree of specialisation more likely to go extinct?
High specialization - species that rely on one food source are vulnerable if that becomes rare
Why are species with high population variability more likely to go extinct?
Population variability - sudden decline can lead to extinction
Why are species with high trophic status more likely to go extinct?
Top carnivores are small in number - prone to extinction
Why are species with short life span more likely to go extinct?
Few years of unfavourable conditions can prevent breeding for a whole lifespan and cause extinction
Why are species with low reproductive ability more likely to go extinct?
Blue whales breed slowly
- and so recover slowly from population declines
What is the most endangered class and why?
Amphibia
Chytrid disease - fungal
What are some dispersal pathways?
- corridors, sweepstakes, filter routes
Range expansion - organisms can move into a favourable habitat or _______ dispersal over unfavourable habitat
Jump
What factors are affecting soil quality and what are they causing in the soil?
Overgrazing
Over-irrigation
leading to
Nutrient exhaustion
Salt build-up
How important is plant-derived C to mycorrhizal fungi?
Obligate biotrophs.
Growth of fungi increases when plants exposed to light
Growth of fungi increases when root associated
How important is the diversity of AM fungi for plant nutrient uptake?
Very important - different AM fungi have different ability to take up nutrients at different distances
- Higher diversity higher uptake
What are some dispersion drivers?
Density - competition for resources (space, food, mates)
Invasion - New organism to ecosystem
What is Conservation Biological Control? Give an example
Conservation Biological Control
- Increase density of native predators
- e.g. reduction of aphids by encouraging ladybirds and other predators by planting suitable habitats
What is Importation Biological Control?
Import a known natural enemy from another geographical area
What is a good pollution indicator for air quality?
Lichen
What is a good indicator of water sewage pollution?
Benthic invertebrates
What are problems with pesticide pollution?
Non-specific toxicity - can kill pest and natural predators
Bioaccumulation - accumulation in food chain (especially predators)
Describe the Plant-aphid-wasp-mycorrhizal interaction
When plants are attacked by aphids
- Produce VOCs that repel aphids and attract their enemies
- Parasitoid wasps
Signalling compounds produced by plants in response to aphid attack transferred via common mycorrhizal networks
Describe an experiment to show how plant carbon is key to soil respiration
- Girdle trees - remove a section of bark all the way round a tree
- At different times in the year - calculate soil respiration for the different areas
- Evidence shows that the difference was due to the mycorrhizal fungi not receiving enough carbon
Name a few Behavioural predation defence mechanisms?
- Flight
- Bluff (threat displays e.g. owl)
- Startle response (moths)
- “Playing dead” e.g. Virginia Opossum,
What % of flowering plants do AM fungi form a relationship with?
80%
What is a interneferon - freshwater systems
Badumcha!
Where do ericoid mycorrhizal fungi dominate?
Acidic nutrient poor environments
- Low N litter forests
- With enchytraeid worms
What advantage does having antifungals (fungitoxic compounds) give to some plants?
Other plants surrounding it which rely on mycorrhizals for nutrients struggle to compete due to antifungal in the vicinity
What are the environmental negatives to aquaculture?
Loss of habitat
- Coastal mangroves
- Wetlands
Nutrient Pollution
- Nitrogen
- Antibiotics
What is Competitive Exclusion Principle (Gause’s Principle)?
- If two competing species coexist in a stable environment, then they do so as a result of niche differentiation
- If, however, there is no such differentiation, or if it is precluded by the habitat, then one competing species will eliminate or exclude the other
What does niche differentiation reduce?
Interspecific competition
- Allows coexistence
Why are monophagous organisms more likely to go extinct?
Eat only one type of food
Specialists - not very adaptable
- If food source disappears they go with it
What are potential benefits of using the mycorrhizal relationship in agriculture?
Reduced fertiliser use
Reduced pesticide use
Carbon accumulation in soil
What is a Biotic Homogenisation and why has it occured? Give an example
Organism faunas becoming increasingly similar due largely to species introductions
Eg. island flightless birds being wiped out by introduced predators
What are some threats to biodiversity?
- Overexploitation by humans
- Habitat Disruption
- Climate Change
- Invasive species
- Infectious disease
What are the benefits of diel vertical migration (DMV) for zooplankton?
Nighttime - migrate upwards
- allows them to feed on surface algae and phytoplankton.
- more safely.
- darkness reduces the risk of predation by fish and other visual predators.
Daytime: descend to deeper
- avoid daytime predators and exposure to harmful UV radiation.
- cooler water - more favourable for their metabolic processes.
