ecology 10 to 13 Flashcards
what is eco-evo?
the study of how ecology change and evolutionary changes are influenced by each other
do ecology and evolution happen on the same time scale? what is the modern vs historical view?
- yes but it is very variable
- modern view is a much more rapid timescale (e.g. 10 generations) but historical view suggested that it isn’t in the same time scale (evolution acts around 500 000 years)
explain how peppered moth show rapid evolution.
- environmental changes due to pollution favored the survival of the dark form over the light form
- causes increased frequency of dark moths
- eventually the dark form constituted more than 90% in heavily polluted areas
- trend reversed back as pollution decreased
what did the predator-prey cycle study of Brachionus calyciflorous and chlorella vulgaris show?
presence of genetic variation affected cycle period and phase
explain the eco-evo dynamics between daphnia and cyanobacteria?
- daphnia graze on plankton
- eutrophication has leas to higher abundance of toxic and nutritionally poor cyanobacteria
- resistance to cyanobacteria toxins has increased through time (variation has increased in recent times, cocurrent with decreased eutrophication)
- cyanobacteria increase in abundance during eutrophication because most grazers cannot consume them (return to previoud conditions has lead to decrease of abundance of species which became more tolerant)
what is evolutionary rescue? how does this occur?
- adaptive evolutionary change restores a positive growth rate to a declining population, preventing extinction
- in the process, a rare but adaptive allele will come to dominate in the population
explain the evolutionary rescue experiment on S. cerevisiae?
- yeast exposed to 125 g/L of NaCl (150 g/L is lethal)
- u-shaped recovery curve is seen
- the population drops by 90% (very strong selection usually results in purging of a genetic variation)
what is the effect of genetic diversity on evolutionary rescue?
increased genetic diversity increased the probability of evolutionary rescue
what is pleiotropic selection?
when multiple forces act on a single trait
explain the rapid evolution of flatwing morph? what type of selection was acting on it? (Crickets)
- male crickets are lethally parasitized by O. ochracea and they find their host by sound
- pleiotropic selection acts on them
- silent males have difficulty attracting a mate but they are unlikely to be affected by the parasitoid fly
A negative correlation between rate of evolution observed in a study vs interval over which the rate is calculated is seen. What are some biological explanations for this pattern?
- when you have a purging of the genetic variant, see a rapid evolution at first, then slows down
- selection can be on both directions
- shows only minimum rate of evolution since doesn’t follow many generations
what is resistance?
the ability of a system to avoid displacement from its current state
what is resilience?
the speed and ability of a system to return to its former state after a disturbance
what ecological and evolutionary attributes affect the resistance and resilience of a population or community?
- generalist predators tend to increase resistance and resilience of a community
- a long-term stable community might be less resilient (e.g. elephant more vulnerable to changing environment then mouse)
- increase genetic diversity helps with resilience but decreases resistance
- lack of genetic diversity will often increase resistance but decrease resilience
what is the Anthropocene?
the age of human impact on he earth; the period of time during which human activities have impacted the environment enough to constitute a
distinct geological change.
rate of extinction has been increasing or decreasing in the last couple hundreds of years? what does this mean for biodiversity?
increasing, which decreases biodiversity
what are the main drivers of biodiversity loss?
- land/ water use
- direct exploitation
- climate change
- pollution
- invasive alien species
what are the two forms of land use change? which is worse?
- loss of area (smaller area)
- fragmentation (less area but it is separated) – this is worse
___% of remaining forest is within 1 km of the forest’s edge, subject to the degrading effects of
_____________
- 70
- fragmentation
what is reduced in fragmented landscapes?
Species persistence, species richness, nutrient retention, succession rate, trophic dynamics,
pollination
does the level of fragmentation affect the loss of biodiversity? how or why not?
yes, if there is a higher level of fragmentation (more smaller squares), there will be less loss
what does an invasive species surviving on a new location tell us? what effect does this usually have on surrounding or native species?
- means that their previous niche was not their overall potential niche (can survive in larger niche than was thought previously)
- usually outcompetes local species for resources
Earth’s temperature average of __°C (with the greenhouse effect), instead of ___°C (without the greenhouse effect)
- 15
- -18
what are ectotherms? what do we know about them?
- animal that is dependent on external sources of body heat (cold-blooded)
- have predictable responses to temperature
what influences continental-scale distributions of species?
climate
what is the difference between expected expansion in warmer and cooler climates?
- warm: Expectation of population declines, or
emigration; Persistence, adaptation, resilience - cool: Opportunity for increased population
growth, immigration, range expansion, invasion, new species interactions, new connections
what are the organismal sources of resilience? how can we help?
- tolerance
- changes in timing and behavior
- range shifts
- acclimation and evolution
we can help by: - habitat restoration and protection
- protect numbers (so evolution is faster)
- design protection “corridors”
- smart actions (e.g. water control for salmon,
plant trees adapted to a future climate)
what are community sources for resilience?
- changes are felt less when diversity is higher
- Some species can replace the roles of others
what is phenology?
timing of events in biology
what is the effect of species not changing at the same pace?
This means new species interactions gained, and lost
what are sources of resilience of Eco-human coupled systems? how can we help?
- human adaptation (move, change relationship)
- new or different couplings (e.g. fish new species)
we can help by: - predicting the changes,
- reducing surprises,
- slowing the change,
- reducing meaningful loss
what are the 3 aspects of an equilibrium community?
- if there is no disturbance, there will be no major change
- if there is a disturbance, the community will return to the equilibrium state
- the effect of history is erased because the species composition ends the same way and remains there.
what is a disturbance?
a discreet event that disrupts community structure, resources, or physical environment
what is resistance?
ability of a community to avoid displacement from its current state
what is resilience?
ability and/or rate at which a community returns to its former state after a disturbance
are negative feedback loops stable? explain.
yes, since where there starts to be more or less of one of the two species, then it equilibrates itself
are positive feedback loops stable? explain.
no since where there is a change in one of the species, then it will just continue to grow or decline exponentially instead of equilibrating itself
what is the cycle of dynamic adaptive systems?
- new resources and opportunities
- growth
- optimal system, loss of diversity, loss of connections
- crash
- recovers with new order
what is biodiversity?
the variety and variability of life on earth
what are the 3 levels of biodiversity?
- ecosystem diversity
- genetic diversity
- species diversity
what is species richness?
the number of species in a community
what is species heterogenicity?
a way to measure species diversity that accounts for # of species and relative abundance of each (the chance of encountering the same species twice)
what is dissimilarity?
a measure of how many total species are not shared between communities
why do some places have more species than others?
- Temperature
- Water
- Sunlight
- More individuals lead to more species
- Species interactions
- evolutionary speed
- disturbance
why might diversity be important?
for ecosystem function:
- productivity
- biomass
- decomposition
other services:
- disease persistence
- stability
what are ecosystem services?
the benefits to humans provided by the natural environment and from healthy ecosystems
