Ch 2 Qs Flashcards
What are three important aspects of experimental design?
Randomization
Replication
Manipulation
What is one potential problem with the controlled field experiment that measured the loss of water and soil nutrients due to deforestation by comparing a forested valley with a cutover valley
If the valleys were at different locations, they likely will be affected by different precipitation levels, and possibly also different climates, different species present, different slope and size of valley, etc.
Connell’s first experiment
- Connell removed Chthamalus from the upper area, and no Balanus replaced it.
- Inference: Balanus could not survive in an area that experienced so much desiccation (due to low tides).
- Conclusion: Balanus’s realized niche was the same as its fundamental niche.
Connell’s second experiment
- Connell removed Balanus from the lower area and Chthamalus replaced it.
- Inference: Balanus was a more successful competitor in the lower intertidal zone.
- Conclusion: the fundamental niche and realized niche for Chthamalus were not the same— it’s realized niche was smaller due to interspecific competition.
Conclusion of Connell’s experiments:
Competition in nature can explain the distinction between a fundamental and a realized niche
How does Radiocarbon dating work?
The half-life is the time taken for an amount of a radioactive isotope to decay to half its original value. Because this decay is constant it can be used as a “clock” to measure elapsed time assuming the starting amount is known
How can you avoid falling for “fake news” stories on social media?
Think skeptically and critically,. Evaluate evidence and hypotheses using inputs from a variety of reliable sources, avoid confirmation bias, evaluate your own biases
The process of science is our best method for understanding the natural world, but it does have some limitations. What are these, and how can we work to overcome them as scientists?
Scientists cannot disprove or disprove anything absolutely
Scientists are not free of bias about their own hypotheses and results
Describe the differences between physical, chemical, and nuclear changes to matter.
Physical- no change to the substance’s chemical composition
Chemical- there is a change in the chemical composition of the substances involved
Ex: combustion is a chemical process in which a substance reacts rapidly with O2 and gives up heat. Original substance is called fuel, and the source of oxygen is called the oxidizer. The new substances created are called the exhaust.
Nuclear- the nucleus of the atom is altered, resulting in a different element
How do we convert potential/kinetic energy into electrical energy that we can use to power our electronic devices?
Turbines and generators
Renewable vs. Nonrenewable energy
R: E gained from resources that are replenished by natural processes in a relatively short time (Wind, H2O, sunlight, trees, etc)
N: E from resources that can be depleted and are not replenished by natural processes within a human time scale
What are some ways that we can access high-quality energy? Is it only by burning fossil fuels?
No- wind, solar, hydro, etc
The first law of thermodynamics might seem to suggest that sustainability is ensured. Matter may be converted to energy and energy converted to matter, but energy and matter in total are conserved, and thus, remains undiminished. Is this true?
No, bc every time energy is converted, some is lost to heat in the atmosphere and becomes low-quality
The second law of thermodynamics might suggest that sustainability is impossible. Is this true?
No, the “openness” of the biosphere, and the fact that the Earth is an “open system” it’s able to store sufficient amounts of “useful” solar energy to offset the declining usefulness of other sources.
What are some examples of positive feedback loops? Negative feedback loops? Which of these are used by natural systems to maintain ecological stability?
Positive feedback loops- Polar ice melting, temperatures rise, and as reflective ice disappears dark water absorbs more heat.
Negative feedback loops- trees falling and creating space for others. Used for ecological stability
