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BIO 2129 Study Guide - Midterm Guide: Exponential Growth, Arctic Ocean, Earth System Research Laboratory

Course Code
BIO 2129
Jeremy Kerr
Study Guide

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Ecology Midterm 1
Lecture 1
Ecology is a science
Environmentalism is a cause
Ecology is the scientific study of the distribution and abundance of species
Critical problems are no very easy to find. You hear about them everyday
Intro to ecology
Science of ecology seeks to solve problems that range in scope from microscopic
to global
Ticks: do well in fragmented landscape. Its a parasite. Wants to go where the host
is. The hosts are mice and deer's. Forest edges. (Local scale)
(Large scale) entire landscape across Canada, North America.
The big picture in ecology:
Life is incredibly diverse in some environments and very sparse in others.
The diversity of life is highest in tropical areas. This is the latitudinal gradient of
species richness. More energy at the equator, more plants, more herbivores…. (Not
entirely sure)
Climate is one of the most dominant factor shaping global biodiversity patterns.
Disturbances can also have dramatic effects at local scales.
Controlled fires are good for ecosystems.
Abiotic factors can exert strong effects on species distribution and abundance.
(Abiotic=non living) in a small amount of space you have a huge different (forest…
non forest)
Biotic factors (e.g. parasitism) cam also affects species distribution and
abundance. (American chestnut were nearly killed by parasitic chestnut blight)
Other interspecific interactions include mutualism, competition, predation, etc.…
(Flower needs a butterfly, flower needs a butterfly)
Interactions between species can be negative as well, e.g. Urushiol is likely an
anti-herbivore defense for toxidendron spp (poison ivy)
Ecology also includes the study of the dynamics of populations
Why do populations sometimes increase drastically? Or disappear? (Flowers
evolve to live in the weather, wait for the rainstorm to grow.) (Brown pelican: use of
DDT, bird’s eggs is bridal. 1960-70s stopped it. Brown pelican pop. Grew)
Questions of population growth and decline can have vast economic implications
(fishing down the food chain or calamari=bait)
oE.g. shark fishing reduced target species populations by 75% in the
western Atlantic between 1986 and 2000
Shark fisheries are managed typically i.e. will collapse soon.

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Terrestrial ecosystems are also subject to massive degradation. Most lands
nowadays are heavily changed
Human activities cause virtually all extinctions
Extinctions are now occurring at a pace comparable to that last seen at the end of
the age of the dinosaurs.
One role of ecology is to provide scientific underpinnings for conservation
This requires knowledge of different forms of natural and anthropogenic change
(e.g. disturbance form human (road), natural (volcanic))
The loss of species is not only an ethical dilemma but a practical one
oSpecies, even rare ones, in ecosystems contribute it ecosystem.
The biophysical processes of an ecosystem are known as ecosystem functions
When those functions benefit humans either economically or otherwise, they are
know as ecosystem (bees)
Ecosystem are responsible for:
oFlood control (wet lands are an amazing way to stop flooding, mangrove
oSoil creation
oRegulation of the hydrological cycle
oAtmospheric regulation
oClimate regulation
oProvision of renewable resources
Ecosystem services were worth ~ 33 trillion.
There are many important ecological problems. Problems range from purely scientific to
entirely applied. Ecological discoveries can exert massive societal influence.
Lecture 2
What is science? Something that has no final answer. Always evolving. Always ask
questions, be curious about what is going on in the natural world.
Where do hypotheses originate?
• Observations
From specific cases general rule (i.e. generalizations)
o It is cloudy it will rain (a generalization)
oI have observed 8 cabbage white butterflies (Pieris rapae)
in this habitat this habitat can only support cabbage white butterflies. Could be the
neighbour hood can only support these butterflies…. Maybe hedges too big they
don’t see it. You can make all kinds of hypotheses.
Where do hypotheses originate?
Imagination and intuition

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oIntuition, imagination
What do you with hypotheses if its wrong…. Reject them… reject false statement. This is
the defining characteristic of science. We can’t prove they are true but we can prove they
are wrong.
Where do predictions come from?
Not science: if you are posing predictions that are untestable.
• For a hypothesis to be testable, it must make predictions that can be refuted (PA, PB, PC).
– e.g. Species A lives everywhere except places to which it hasn’t dispersed and/or did not
– e.g. Species A inhabits in which it can tolerate environmental conditions???
(reject the 2nd hypothesis, no way to reject the 1st one. No experiment you can to falsify it)
• Distinguishing between hypotheses requires mutually exclusive predictions.
– For example, H1 = H2 if H1PA & PB and H2PB & PA. In this example, the
hypotheses predict the same things, so they are not really different hypotheses).
• Reasoning: general rule specific examples
– Example: All people are mammals. I am a person. Therefore...
– Example: X2-4=0 . So...
– Example: Alberta has cities. Edmonton is a city.
• So, does deductive reasoning necessarily prove how the world works?
– Watch out for errors in deductive reasoning.
oNo… logical reasoning.. Deductible reasoning.
oIt does not tell u how the world actually works. Got to do some
Deductive reasoning is used to identify what should be observed, if the hypothesis is
actually correct!
Hypothesis: Climate change results from [CO2]atm change.
Prediction: Temperatures will rise if [CO2]atm rises.
• If tests of the prediction are incorrect, then ...
• What do you conclude when temperature rises at the same time as [CO2]atm? \
Other things can change global tempos… but this is more or less can conclude this…
even though with solar cycles and volcanic explosions. But today co2 is the main
reason sop you can conclude that
A common form of deductive reasoning error is known as “affirming the consequent”:
– Deduction: IF H1 is true, THEN P1 must also be true.
– If P1 is true, is it necessarily true that H1 is correct?
The plant killed its caterpillar by producing cyanide… but even though it can be killed by
many other things.
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