Bio 94 Midterm 4 Flashcards
What is ecology?
The study of how organisms and the environment interact
What are the 5 levels of ecology?
- organisms
- populations
- communities
- ecosystems
- the globe
What is Organismal Ecology?
studies morphological, physiological, and behavioral ADAPTATIONS
What are Adaptations?
heritable traits that increase an individual’s fitness
What is Population Ecology?
studies number and distribution of individuals & pop. change over time
What is a Population?
a group of individuals of the same species, same area, same time
What is Community Ecology?
“food webs”/ interactions between species
eg. predation, parasitism, competition, natural disaster responses
What is Ecosystem Ecology?
studies ALL organisms and abiotic factors
eg. nutrient or energy pathways
What is Global Ecology?
studies everything encompassed by the biosphere, focusing on the effects of human impacts on the biosphere
What is a Niche?
the range of conditions a species can tolerate and resources it can use; product of abiotic & biotic factors
What are Fitness Trade-offs?
-evolutionary compromises between traits that cannot be optimized simultaneously
–> limits environmental conditions in which a species lives
eg. rocket commuter
What is Dispersal?
an organism’s movement from place of origin to the location where it lives and breeds as an adult
What is Weather?
short-term atmospheric conditions
What is Climate?
long-term weather conditions
Why are the tropics are warm and the poles are cold?
-angle of incidence of the sun
(tropics more concentrated, poles same amount of E over a larger distance–> weaker per sq ft)
What is the cause of the seasons?
the tilt of the Earth (southern hemisphere vs. northern hemisphere)
What is a Hadley Cell?
-air warms up at equator, rises, replaced by sunken cool air, forms a convection current
What area receives the most moisture?
the equator
What areas are the driest?
30° N/S latitude
What is the Coriolis effect?
the Earth’s rotation causes wind and ocean currents to deflect in a spiral pattern
eg. Westerlies & Northeast trade winds
Which direction does the Northern Hemisphere’s air and water currents flow?
CLOCKWISE; leftward deflection
Which direction does the Southern Hemisphere’s air and water currents flow?
counterclockwise; rightward deflection
What is a Rain Shadow?
when moist air blows up from a mountain range, cools and produces rain; cool, dry air passes over –> desert
How does a Rain Shadow affect climate?
can modify climate patterns
How do Oceans modify climate?
moderating effect due to high specific heat
1. absorb summer heat, release winter
2. coastal areas–> moderate climate
3. gyres (circulate warm & cool water)
What are biomes?
regions characterized by distinct abiotic characteristics and dominant vegetation types; determined by precipitation and temp.
NPP stands for
Net Primary Productivity: total biomass (organic matter available)
Arctic tundra
low precipitation, low temps.
Boreal forest
low precipitation, low temps.; presence of trees
Temperate forest
mid precipitation, higher temps.; presence of trees
Temperate grassland
mid precipitation, higher temps.
Desert and dry shrubland
low precipitation, high temps.
Tropical wet rainforest
high precipitation, constant temps., presence of trees
What are simulation studies?
computer models
What are observational studies?
long-term monitoring
What are historical studies?
historical events
Experiments
simulate changed climate conditions and record organisms’ responses
Tipping Points
cause abrupt changes in biomes
eg. Amazon rainforest–> grassland
(feedback loops–> stability–> effect on biodiversity)
-Very dangerous OR very good
Abiotic factors (aquatic biomes)
- Salinity
- Water depth (light)
- Water flow
- Nutrient availability
Coastal runoff
streams into estuaries into oceans; carry nutrients
Ocean upwelling
Coriolis forces (wind blows, surface water moves, filled by nutrient dense “under” water)
Lake turnover
seasonal mixing events caused by temperature gradients THERMOCLINE (winter-colder surface, summer- warmer surface)
Intertidal zone
submerged @ high tide, exposed @ low tide (extreme environment)
Neritic zone
continental shelf (coral reefs)- nutrient dense w/ sunlight
Oceanic zone
“open ocean” (deep water); nutrient scare, sunlight available
Benthic zone
bottom of the ocean (nutrient sink)
Photic zone
regions that are sunlit
Aphotic zone
areas that do not receive sunlight
Littoral zone
lake “seashore”; plants can rooT
Limnetic zone
lake, sunlight, too deep for plants to root
What is behavioral ecology?
under organismal, studies behavioral adaptations
Proximate causation
aka mechanistic HOW ACTIONS OCCUR
Ultimate causation
aka evolutionary, WHY ACTIONS OCCUR
Optimal foraging
choosing what, how and when to eat (usually to avoid competition)
Evolutionary Game Theory
behavioral strat of one player depends on how it perceives the behavior of others (in relation to others)
promiscuity
each individual has multiple mates
Intersexual selection
between sexes eg. peacocks
Intrasexual selection
within a sex eg. rams
Deceit
only works when it is relatively rare
Altruism
a behavior where survival or reproduction is sacrificed for another’s gene to succeed
Hamilton’s Rule
Br>C
if the benefit > cost then likely to engage in behavior (r=coefficient of relatedness)
more related—> more likely to benefit “your” genes
Inclusive fitness
both direct and indirect fitness
Direct fitness
from an individual’s own offspring
Indirect fitness
derived from helping relatives; not your genes, but from your gene pool
Kin selection
natural selection that acts through benefitting your relatives —> indirect fitness
Reciprocal altruism
“down payment” an exchange of fitness benefits separated in time
Mutualism
cooperations between individual of different species
metapopulation
populations of populations connected by migration
what adds to a population?
births and immigration
what subtracts from a population?
deaths and emigration
age structure
number of individuals of each age; lots of young—> grow; lots of old—> decline
Life table
probability that an individual will survive and reproduce at any given time
fecundity
number of female offspring produced by each female in the pop.
Type I curve
——|
| eg. humans
Type II curve
\
\
\ eg. song birds (steady survivorship)
Type III curve
\
\
———- eg. insects, plants
mortality early on, high survivorship once established
r (population growth)
births—deaths
When can exponential population growth occur?
when r does not change
When does a population size stop changing?
1) deltaN=0 (doesn’t exist)
2) b=d (r=0) inviable
3) when k=N (@ carrying capacity)
Discrete pop. growth equation
N(total)= N(0)r^t
Continuous pop. growth equation
N(total)= N(0)e^rt
exponential growth is density independent
population size does not limit growth rate
When does exponential growth occur in nature?
1) colonization of a new habitat
2) recovery after a disaster
Why do some populations crash?
overshoot (go over k), can degrade the environment
Competition
use the same resources (-/-)
consumption
(+/-)
Commensalism
one species benefits, but the other is unaffected (+/0)
eg. epiphytic orchids
Mutualism
mutual benefit (+/+)
amenalism
(-/0) eg. stepping on a bug, OR tree shading grasses (blocks sun)
Intraspecific competition
within a species
Interspecific competition
between diff. species
Niche overlap
—> competition, fundamental niche—> realized niche
Compete niche
stronger competitor drives other to extinction
Competitive exclusion principle
better competitor wins
fundamental niche
theoretical range of conditions a species can tolerate
realized niche
portion of fundamental niche the species actually occupies (what actually occurs)
Niche differentiation—> character displacement
natural selection favoring one part of the niche—> can evolve to avoid competition of resources
Types of consumption
1) Predation
2) Herbivory
3) Parasitism (endo, ecto, parasitic- free living as an adult, but lay eggs/larvae in host)
succession
recovery after a severe disturbance
Primary succession
grow back with nothing
Secondary succession
some organic material left over
What determines succession?
1) Dispersal (which species arrive first?)
2) Pioneering (which species thrive in disturbed/no soils?)
3) Community development (What happens to the composition as time passes?)
Facilitation
occurs when early-arriving species make conditions favorable for later species
4 nutrient cycles
water, phosphorus, nitrogen, carbon
GPP
gross primary productivity; total chemical energy produced in a certain area
NPP in deserts v coral reefs
low high
NPP tropical wet forests (rain forests)
incredibly productive, modest amount of Earth’s surface
NPP open ocean
low productivity, but occupy the majority of earth’s surface; largest share of NPP
grazing food chain
primary consumers and those that eat primary consumers (herbivores—> predators)
decomposer food chain
decomposer that feed on plant detritus
Energy through trophich levels
decreases 90% (used for life of organism); only 10% transferred
water table
upper limit of the underground layer of soil saturated with stores water
nitrogen cycle is affected by
eutrophication (over fertilization)—> algae blooms and “dead zones”
What is the major reservoir of nitrogen?
aquatic organisms and terrestrial
Major reservoir of water
ocean
major reservoir of carbon
ocean
Fossil fuels are?
1) energy dense
2) easily burned to produce energy
3) accessible
4) CO2 waste product
How to measure diversity?
1) Species diversity (richness/evenness)
2) Phylogenetic Diversity (across the tree of life)
3) Functional Diversity (roles eg. primary producer, decomposer, etc.)
How does diversity affect NPP?
increased diversity, increases NPP
How does species richness positively impact NPP?
1) increases resource use efficiency
2) facilitation
3) change inclusion of high-productivity species (increases chance to find highly successful organisms)
Horizontal diversity
number of species in each trophic level
Vertical diversity
number of trophic levels
Diversity increases
resistance AND resilience
(how much resist getting knocked down)
(how quickly can return)
Ecosystem Services
1) Provisional (food, medicines)
2) Regulating services
3) Cultural services
4) Supporting services
Major Threats to Biodiversity
1) Habitat Destruction
2) Overexploitation
3) Invasive species/Disease
4) Pollution
5) Climate Change
Conservation Strategies
1) Education campaigns
2) Ex situ conservation (captive breeding)
3) Genetic restoration (intro. gene flow)
4) Wildlife corridors (tunnels/bridges)
5) Seed bankers
6) Designating effective protected areas (national parks)
7) management plans for invasive species
8) Ecosystem restoration
9) Management plans for threatened species
10) Quantifying ecosystem services (tourism)
