Eco-Evo in Streams

Question 1

Name 3 ecosystem affects on evolution.

Answer 1

Ecosystem affect on phenotype
Communities affect on phenotype
Populations affect on phenotype

Question 2

Name 3 evolution affects on ecosystem.

Answer 2

Phenotypes affect on ecosystem
Phenotypes affect on communities
Phenotypes affect on population

Question 3

There are two ways you can measure contemporary phenotypic evolution, name them and what is the main difference between these two?

Answer 3

Allochronic studies – same population measured at two points in time
Synchronic studies – different populations (usually recently separated) measured at the same point in time

Question 4

A researcher samples multiple populations of steelhead, which were introduced in early 1900’s to a lake in California, is it allochronic or synchronic study?

Answer 4

Synchronic study, because they are multiple populations that are being sampled now.

Question 5

A researcher introduces guppies into a new stream and tracks changes over a decade, is it allochronic or synchronic study?

Answer 5

Allochronic study, because the same population is being tracked over time.

Question 6

What are the strength and weaknesses of Allochronic studies?

Answer 6

Strengths:
○ Understanding Long-Term Trends:
w Reveal how ecosystems respond to gradual changes like climate change, land use changes, or species invasions.
w Provide insights into historical baselines, helping to distinguish natural variation from human-induced changes.
○ Identifying Causal Relationships:
w Can link past events (e.g., pollution, dam construction) to long-term ecological impacts.
○ Predicting Future Dynamics:
w Historical data can inform models to forecast how ecosystems might respond to ongoing changes.
○ Evolutionary Insights:
w Highlight species adaptations over time, offering a broader perspective on resilience and vulnerability.
Weaknesses:
○ Data Availability:
w Long-term data are often scarce or incomplete, especially for understudied systems.
○ Time and Resource Intensive:
w Collecting and analyzing data over long timescales requires significant time and resources.
○ Retrospective Bias:
w Historical records (e.g., sediment cores or archival data) may have inconsistencies or limited resolution.
○ Complexity in Interpretation:
w Multiple interacting factors over time make it challenging to isolate specific drivers of change.

Question 7

What are the strength and weaknesses of Synchronic studies?

Answer 7

Strengths:
○ Efficiency:
* Easier and quicker to conduct, as data are collected within a short timeframe.
○ High Resolution:
* Provides detailed snapshots of current ecosystem conditions, useful for assessing immediate concerns (e.g., pollution events).
○ Comparative Analysis:
* Enables spatial comparisons across multiple sites or ecosystems at the same time.
○ Baseline Data:
* Useful for establishing current ecological baselines to inform management and conservation efforts.
Weaknesses:
○ Lack of Temporal Context:
* Fails to capture how ecosystems change over time, limiting understanding of trends or processes.
○ Snapshot Bias:
* Ecosystems are dynamic, so data from a single moment might not represent long-term conditions or variability.
○ Limited Predictive Power:
* Without historical context, it’s harder to predict how ecosystems might respond to future changes.
○ Missed Slow Changes:
Slow processes (e.g., sediment accumulation or species adaptation) are not observable in short-term studies.

Question 8

What is the definition of phenotypic plasticity?

Answer 8

Phenotypic plasticity: the ability of an organism to change its phenotype, or observable traits, in response to environmental conditions.

Question 9

Write the equation of phenotype.

Answer 9

Phenotype=G+E+GE

Where:
* G = Genotype
* E = Environment
* GE = Interaction

Question 10

There are two experiments that can determine if the phenomenon is evolution or phenotypic plasticity, what are they and what is the main difference?

Answer 10

1. Common Garden Experiments
   rear populations in single environment, hold E constant to measure effect of G
2. Reciprocal Transplant Experiments
   rear populations in multiple environments, allows estimation of G, E, and GE

Question 11

What is the difference between plasticity and evolution?

Answer 11

Plasticity is when you put the population in a different environment and there is change in the phenotype.
Evolution is when you put multiple population in a same environment and they have different plasticity.

Question 12

Draw graphs on:
1. No plasticity, no evolution
2. Yes plasticity, no evolution
3. Yes plasticity, yes evolution
4. No plasticity, yes evolution
4. Yes plasticity, yes evolution, G*E interaction

with phenotype on the y-axis, and environment on the x-axis