Exam 3 Study Guide

Species richness

number of species within a community

Species diversity

measure of community structure that combines
number of species and abundance compared with other species

species eveness

describes commonness (or rarity) of species within a community

community

group of interacting species

functional group

organisms that function in similar ways but
may/may not use similar resources

guild

group of species that use the same resources

facilitation cascade

indirect positive effect of another species on a consumers prey that benefits the consumer

trophic cascade

indirect effects of consumers on resources

keystone species

strong interactors that have large effects on
communities because of their role not abundance or size

hyper-keystone species

species that drive complex interaction chains
by affecting other keystone actors

ecosystem engineer

organisms that directly or indirectly
modulate availability of resources by causing physical state changes in abiotic or biotic materials

foundation species

organisms that have large effects
on communities because of their size and abundance

Temperate forests; tropical soil bacteria

Which of the following datasets is most well sampled? Which is least well sampled?

Sequential megafaunal collapse hypothesis

the name of the proposed explanation for this shift in the ecological community of kelps in Alaska

niche partitioning, species interactions, neutral models, intermediate disturbance hypothesis

4 mechanisms that explain coexistence

ecosystem function

broad term encompassing the biological activities that maintain life

ecosystem services

natural processes that sustain human life

high; low; trophic skew

Fill in the blanks. Extinctions are biased towards __________ trophic levels. Invasions are
biased towards ________ trophic levels. Even if overall species richness is constant, these
combined effects can lead to _________.

c. Only some plants take up marine N at spawning creeks

The following table summarizes δ15N measurements from plants at spawning creeks (with salmon) relative to reference creeks (no salmon). What pattern does the data suggest?
a. Plants are taking up marine N at both creeks
b. Plants are taking up marine N at spawning creeks
c. Only some plants take up marine N at spawning creeks
d. Salmon are delicious

d. Movement, transformation

Biogeochemistry is the study of the physical, chemical, and biological factors that
influence _______ and ______ of chemical elements
a. Transfer, conversion
b. Flow, modification
c. Transport, metamorphosis
d. Movement, transformation

plant; anthropogenic; minerals

What are the three main sources of nitrogen-based nutrients and explain how each enters
the ecosystem.

nitrogen fixation

uptake of N2 and conversion to usable form

strong bonds

Why is Nitrogen a limiting nutrient when it is the most abundant component of Earth’s
atmosphere?

autogenic engineer

change environment with their own physical structurea

allogenic engineer

change environment by transforming living or non-living materials

weather

actual state of the atmosphere at a particular time

climate

statistical description of weather over a period of time

They provide a lot of nitrogen and iron

Explain the role whales play in the facilitating the ocean's biological pump

Correlation; Seuss Effect; Declining CO2_; Energy budgets

How do we know that climate change is driven by anthropogenic sources?

CO2 is rising; NH has more people and land mass; season variability; Mauna Lona 20% CO2 increase

What are some patterns in the Keeling Curve and Pump handle video?

plants have a higher ratio

How do animals and plants differ (or not) in their C:N ratios