Prelim #2 Flashcards
human development index
a summary measurement of average achievement in key dimensions of human development: a long and healthy life, being knowledgeable and have a decent standard of living
what kind of population growth is being exhibited by the world’s human population?
greater than exponential, increasing r
pre agricultural period
- 100,000 years
- hunters and gatherers
- ten of thousands of years for population to double
- population 5-10 million at end
agricultural period
- began 10,000 years ago
- domestication of plants and animals
- doubling time ~1,000 years
- 500+ million at end of period
industrial period
- ~200 years ago
- current period
- advances: technology, fossil fuels, sanitation, medicine
- death rates decline
- doubling time ~50 years
life expectancy: rich vs poor countries
- going up worldwide
- higher in rich countries
- influenced by wealth/development, nutrition, healthcare, sanitation
cause of death in rich vs poor countries
rich: chronic illness: heart attack, stroke, cancer
poor: infectious disease, pneumonia, HIV/AIDS, malnutrition, diarrheal disease
infant mortality rate in rich vs poor countries
poor countries’ have a rate that is 13 times higher than rich countries
fecundity
- potential for reproduction of an organism
- differs between developed and less developed nations
- number of births in US is 2 compared to 7 in Niger
people in poorer nations…reproduce….and …..
- reproduce more and sooner
- birth rates lower in richer countries
demographic transition model: stage 1
- preindustrial/pretransition
- before economic development
- death rate high
- birth rate high
demographic transition model: stage 2
- transitional
- mortality transition
- death rate decreases
- birth rate stays high
- rapid population growth
demographic transition model: stage 3
- industrial
- fertility transition
- death rate stays low
- birth rate decreases
- population growth slows
demographic transition model: stage 4
- post-industrial
- stability transition
- low birth and death rate
- birth and death rates equal
- zero population growth
demographic transition model: Niger vs. Netherlands
- niger is in stage 2, approaching stage 3
- netherlands is in stage 3, approaching stage 4
demographic transition model: 5th stage?
- declining birth rate
- declining death rate (not as much as birth rate)
- declining total population
how to help a starving nation?
- not food, that just increases K slightly, does not decrease population growth rate
- education
reduction of birth rate seen with
- economic development
- educational opportunities for women
- empowerment of women
IPAT equation
I=P*A*T I=environmental impact P=population size, growth, distribution A=affluence (individual consumption) T=technology (energy using items)
Exploitation
+/-
predation, herbivory, parasitism
competition
-/-
2 plants next to each other (limited light)
a cheetah and a lion fighting over carcass
mutualism
+/+
- pollination, cleaner fish, seed dispersal
- association between individuals of 2 species in which each parter benefits from the association
- benefits: fitness, population growth, across the ecosystem overall
neutralism
0/0
dog and cat sniff each other and then walk on
commensalism
+/0
phoresy (biological taxi service, mites use birds for transportation)
ammensalism
-/0
elephants or cows stepping on plants
how are interactions asymmetric?
positive can be more extreme for one organism, negative can be extreme negative (death for one dinner for other)
place interspecific interactions into definition of hierarchical framework for ecology
population ecology: emphasis on relationships with interacting species
obligate mutualism
fundamental for survival
facultative mutualism
not necessary to survive, but it benefits both to remain together
3-way obligate symbiotic example
cellulase producing bacteria live in gut protist which lives in termite, bacteria and protist get place to live, termite is able to digest food
defensive mutualisms
- mostly facultative
- species receive food/shelter from partners in return for defending predators against herbivores, predators, or parasites
ex: aphids
mutualism: by-product
not costly, a benefit that comes from the “regular” activities of the partner
ex: aphid excrement drunk by ants, mixed species flocks
mutualism: investment
costly product or service for the partner, typically not needed for self
ex: nectar produced by plants, nitrogen fixed by rhyzobia
mutualism: purloin
costly product taken/stolen from partner
ex: plant pollen fed to bee larvae, blood taken by oxpeckers
conditionality
how environmental conditions impact the strength and direction of interaction outcomes
conditionality is common when
- interaction is facultative
- interaction is indirect (has multiple partners
- density/spatial distance of partner matters
exploitative interactions: low lethality, high intimacy
parasites, flea, common cold, vampire bat
exploitative interactions: low lethality, low intimacy
herbivores, deer
exploitative interactions: high lethality, low intimacy
predators, trout (eats minnows)
exploitative interactions: high lethality, high intimacy
parasitoids: wasp (lays eggs inside caterpillar and eggs eat it from inside out)
how do animals defend against predators?
- color matching (crypts, camouflage, nocturnally, mimicry)
- toxicity (aposematism, venoms)
- behavior (running away, hiding, aggregation, vigilance)
- physical armament (turtle shell)
- size refuge
how do plants defend against herbivores?
- toxicity/chemical defense
- physical armament (spines, hairs, bark, thorns)
- phenological escape
- bodyguards
- behavior (moving away_
- color matching (crypsis)
- plants can’t run away the same way animals do
why is nicotine inducible?
costs are important: may be energetically or ecologically costly
plant defense hypothesis
plant produces chemicals to ward off herbivores but lets in pollinators
parasitoid
- insect that lays one or a few eggs on or in a host organism, which the resulting larvae remain with, consume, and kill in the process
- functionally equivalent to a predator
parasites
a relationship in which an organism lives on or in the tissue of its hosts, often reducing the fitness of the host , but not generally killing it
microparasite characteristics
microscopic, includes bacteria, viruses, protozoans, some fungi, numerous per host, short generation time, multiply directly in host, many intracellular, often induce immunity to reinfection, moderate to high ability to regulate host population
macroparasite characteristics
relatively large, include parasitic worms, ticks, fleas, some fungi, low to intermediate densities per host, relatively long generation time, grow but do not multiply within host; persist by continual reinfection, live in body cavities or on body, induce short-term immune response, low ability to regulate host population
ectoparasite advantages/disadvantages
lives outside organism
- advantages: ease of dispersal and safer from host’s immune system
- disadvantages: vulnerability to natural enemies, exposure to external environment, feeding more difficult
endoparasite
advantages/disadvantages
lives inside organism
- advantages: ease of feeding, protected from external environment, safer from enemies
- disadvantages: vulnerability to host’s immune system, dispersal difficult
what does disease spread depend on?
population density, transmission rate, infectious period
what is R0?
basic reproductive rate, the number on average, of susceptible individuals that each host infects
R0=# susceptible individualstransmission rateInfectious period
if R0=1?
each host infects one new host and the disease prevalence remains constant (replacement level)
if R0>1
each host infects more than one new host and the disease prevalence is increasing
if R0<1
each host infects less than one new host and the disease prevalence is decreasing
What does vaccination do to R0?
decreases the number of susceptible individuals so decreases R0
what else affects R0?
hand washing, minimizing contact with sick, rest and recovery, medicine, developing immunity to a disease, behavioral avoidance of sick individuals, behavior changes to minimize contact with a vector, changes in populations of intermediate vectors, environmental conditions (stress could increase disease prevalence)
exploitative/resource/scramble competition
competition between individuals by reducing the availability of shared resources
interference/contest competition
direct competition between individuals for scarce resources by one impeding or denying access to the resource by another
intraspecific
occurs among individuals of the same species
interspecific
occurs between individuals of different species
competitive exclusion
when 2 species are very similar, they may not be able to coexist because competition is so strong. one species may consume all the resources leaving little for the other
when one species is a better competitor, the other should go locally extinct. in the case of the gerbils, the 2 species coexist. why?
- time has been insufficient to allow exclusion
- the environment is temporally variable
- the environment has spatial variation
- there is immigration
- there are multiple resources
niche concept
the range of environmental conditions and resources with which individuals of a species survive, grow, and reproduce
fundamental niche
the full hyper volume or range of environmental factors permitting a species to survive and reproduce (think abiotic)
realized niche
the conditions under which an organism actually exists, after limitations by factors such as competition, disease and predators (think biotic)
which is smaller, fundamental niche or realized niche?
realized niche is typically smaller and can be smaller on numerous n dimensions
niche as an n-dimensional hypervolume
concept of the niche is based on a species tolerance and use of a series of n environmental factors and resources.
can define multiple (n) biotic and abiotic resource axes, each with a certain frequency distribution
giving up density
used with animals that have diminishing returns with foraging
quit when the costs=benefits
evolutionary stable strategies
behavioral strategy that is adopted by a population that cannot be invaded by another strategy
- all members of a population adopt the strategy
- no other strategy will yield a greater benefit to individuals over the long term
assemblage
a taxonomically related group that occurs in a geographical area
guild
a group of organisms that utilize similar resources in a similar way (seed eating vs insect eating birds)
community
a group of interacting species that occur together
community ecology
the study of two or more species, their interactions and consequences for dynamics, persistence, relative abundance of species and diversity
community structure
static properties such as species richness, relative abundance, and distribution
community function
dynamic properties that affect the flow of energy and nutrients (primary production, species interactions, decomposition)
super-organism view
community members tightly bound and integrated, due in part to shared evolutionary history (Clements)–> interdependent model
individualistic view
species are distributed independently of others, interactions are generalized or replaceable (Gleason)–> independent model
ecotones
- regions of rapid replacement of species along an environmental gradient
- represent zones of transition between discrete communities
species richness
number of species present
evenness
degree of similarity (equality) in relative abidance of different species
alpha diversity
local diversity within a habitat, # of species within habitat
beta diversity
among-habitat diversity, measured as species turnover between habitats
-calculated as gamma/alpha diversity
gamma diversity
number of species in all habitats within a region (# of species across all habitats)
bottom-up controls
nutrients/energy (primary producers) limit the food chain
top-down controls
predators influence lower levels
trophic cascade
influence of predators at top of food chain flows downward among multiple trophic levels
what happens when predators eat competitive dominants first?
as predation intensity increases, prey diversity increases up until the apex when diversity decreases(at a certain point if there are too many predators everyone dies)
what happens when predators eat competitive subordinates first?
as predation intensity increases, prey diversity decreases
dominant species
a strongly interacting species that has high biomass in a community
keystone species
a strongly interacting species whose impact on the community is large and disproportionately great relative to biomass
ecosystem engineers
organisms that directly or indirectly influence the availability of resources to other species by creating, modifying, and maintaining habitat structure (beavers, termites)
community importance
change in community structure that results from removing that species
