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Evolution/Community Ecology

Terms in this set (137)

biological evolution can occur through _____, ____, _____, and ____
mutation
migration
genetic drift
natural selection
change over time
evolution
a sequence of DNA that codes for a particular trait
gene
all the genes present in a population
gene pool
the change in a population's gene pool over time
biological evolution
Often biological evolution leads to changes in the frequency of an _____ or _____ from generation to generation
appearance
behavior
accidental change in DNA that can give rise to variation among individuals
mutation
movement of individuals into (immigration) or out of (emigration) a population
migration (gene flow)
Over generations_______ occurs because the gene pool has changed
biological evolution
Called gene flow b/c genes are flowing into and out of population due to _______
migration
evolution that occurs by chance (b/c a natural event happens)
genetic drift
-"survival of the fittest"
-process by which traits useful for survival and reproduction are passed on more frequently than those that are not
natural selection
_______ and _______ proposed the concept of natural selection as a mechanism for evolution and as a way to explain the great variety of many things
Charles Darwin
Alfred Wallace
_______ published a book on the origin of species, which he presented decades worth of scientific evidence for natural selection he had gathered
Darwin
Darwin got on _______ to sail around the world (5 year long trip)
HMS Beagle
4 primary processes of biological evolution
mutation
migration
genetic drift
natural selection
natural selection follows 3 straight forward conditions
variability
heritability
differential reproduction
individuals vary in characteristics
variability
due to genes; the characteristics are heritable
heritability
organisms produce more offspring that can survive better than others without a certain trait
differential reproduction
Individuals with helpful ________ are better suited to their environment
variations
describes how reproductively successful an organism is in its environment
fitness
a heritable trait that increases an individual's fitness
adaption
fitness leads to ______
adaption
An individual with ____ fitness produces more offspring and therefore passes on its genes more frequently than an individual with ___ fitness
high
low
selection under human direction
artificial selection
______ and ______, combine to produce the diversity of life on earth
speciation
extinction
process by which new species are generated
speciation
speciation Can occur in a number of different ways; the most important way is called ______
allopatric speciation
-starts with single population
-Individuals within population mate with one another and share genetic information
allopatric speciation
if the population is somehow broken up into smaller isolated populations
geographic isolation
individuals from one population cannot mate with individuals from the other population
reproductive isolation
Mutations that arise in geographic or reproductive isolation of these isolated populations cannot _____ to the other population
spread
each population creates its own mutations
genetic divergent
Eventually the populations become different enough that their members can no longer mate with one another even if they were not ________ separated
geographically
Long term geographic isolation of populations that can lead to allopatric speciation can occur by
Glacial ice sheets moving
Major rivers changing course
Dry climate partly evaporate a lake, subdividing it into smaller bodies
the disappearance of species from Earth
extinction
The rate at which this type of extinction occurs is known as
background extinction rate
Best known mass extinction occurred __ million years ago and wiped out the ______
65
dinosaurs
extinction occurs gradually, one species at a time, when environmental conditions change ______ than the species can ____
more rapidly
adapt
an organism's niche is affected by its _____ and its __________
tolerance
competitive interactions
describes an organism's use of resources and functional role in a community
niche
its ability to survive and reproduce under changing environmental conditions
tolerance
____ is affected by organism's tolerance
niche
-Some organisms have restricted tolerance ranges
-can eat only certain food or live in a certain habitat
specialists
example od specialists
panda bear
Organisms with a wide range of tolerances are able to live in a wide array of habitats or use a wide variety of resources
generalists
example of generalists
rats
cockroaches
organism's tolerance is affected by
competition
have little competition and do very well in stable ecosystems, but may not be able to adapt to condition changes
specialists
able to live in many different places in variable weather conditions, they can easily adapt to changing conditions, but suffer from intense competition, and may not be successful in a stable environment
generalists
-the full niche of a species
-Everything an organism could do and all the resources it could use if there was no competition
fundamental niche
-niche restricted by competition
-Part of fundamental niche that the organism actually uses
realized niche
Organisms compete when they seek the same ________
limited resource
Can take place among members of the same species
(dogs fighting over a toy)
intraspecific competition
Competition among members of different species
(lions and leopards compete for same food source)
interspecific competition
occurs when one species uses a resource faster or better than the other species even though both species have equal access (plant growing faster to stay in the sunlight)
exploitation competition
one species interferes with or prevents another species from using a resource even though there is plenty of that resource (lions drinking at watering hole, no one else will go there)
interference competition
one species can entirely exclude another from using resource
competitive exclusion
Can happen when 2 or more species try to occupy the same niche
competitive exclusion
To reduce competition, species often partition resources that can lead to character displacement
resource partitioning
Hawks and owls; hawks hunt during day, owls hunt at night is an example of
resource partitioning
Sometimes resource partitioning can lead to the evolution of _________ among competing species that reflect their specialized role in their environment
physical characteristics
____, _____, _____ are interactions in which once species benefits while the other is harmed
predation
parasitism
herbivory
the process by which an individual of one species (predator) hunts, kills, and consumes an individual of another species (prey)
Predation
Interactions b/w predators and prey influence community structure by determining ______of predator and prey
numbers
Causes cycles in predatory and prey population sizes
predation
predation is a ______ feedback loop
negative
Defensive traits such as ______, ______, and________have evolved in response to predator-prey interactions
camouflage
mimicry
warning coloration
Ex. Of Camouflage
leaf bug
ex. of mimicry and warning colors
Coral snake (venomous) and milk snake(nonvenomous)
the process by which 2 species evolve in response to changes in each other
(rough-skinned newt)
coevolution
one organism (the parasite) relies on another (the host) for nourishment or for some other benefit
parasitism
The host is harmed and the parasite benefits in _______
parasitism
Unlike predation ______ doesn't result in an organism's immediate death
(flee, tick, mosquito)
parasitism
long lasting and physically close relationship in which one organism benefits
symbiosis
when an animal feeds on a plant
herbivory
examples of plants that produce chemicals that are toxic or distasteful
Oleander (heavily toxic)
Buttercup (distasteful)
examples of plants that have spines, thorns or irritating hair
Cacti
roses
in response herbivores can evolve ways to overcome these defenses
Birds w/ long thin beaks can go in-between cacti's spikes
______ and ______ are relationships in which neither participants are harmed
mutualism
commensalism
a relationship in which 2 or more species benefit
mutualism
Most mutualisms are ______
Ex. Lichen
Clown fish and anemone
symbiotic
Most important mutualism pollination evolves ______ organisms that encounter each other only once in their lifetime
free living
a relationship in which one species benefits while the other is unaffected
commensalism
example of commensalism
Spanish moss in trees
organisms are classified as either ____ or ____ based on how they obtain energy and nutrients
producers
consumers
All life requires _____
energy
the ability to do work
energy
Energy moves in a one way stream, it is not ____
recycled
-capture energy from the sun or from chemicals and store it in the bonds of sugars, making it available to the rest of the community
-autotrophs
primary producers
the ultimate source of energy for nearly all ecosystems
sun
-hydrogen sulfide is used to convert carbon dioxide in water into sugar
-6CO2+6H2O+3H2S-->C6H12O6+3H2SO4
chemosynthesis
-rely on other organisms for energy and nutrients
-heterotrophs
consumers
Consumers make use of the chemical energy stored by photosynthesis or chemosynthesis in a process called _______
cellular respiration
use oxygen to break bonds in sugar and relates its energy through cellular respiration
cellular respiration
plant eaters (most primary consumers)
herbivores
______ consumers eat secondary consumers
tertiary
meat eaters
carnivore
combination eaters
omnivore
recycle nutrients within the ecosystem by breaking down nonliving organic matter
detritivores
decomposers
example of detritivores
millipede
Large detritivores are often called
scavengers
example of scavengers
buzzard
break down nonliving matter into simpler parts that can then be taking up and used by primary producers
decomposers
example of decomposers
bacteria
Without _______and ________ nutrients would be lost to the ecosystem when an organism dies
detritivores
decomposers
______ transfer b/w organisms shapes the structure of a community
inefficient energy
An organism's rank in a feed
trophic level
primary producers always occupy the __ trophic level
1st
Relative amounts of __________ available at each trophic level put restrictions on a community structure
energy in nutrients
only about 10% of the energy available at any trophic level is passed to the next; most of the rest is lost to the environment as heat
10% rule
Explains why there are so few tertiary consumers and why tertiary are so disturbed by ecological differences
10% rule
the mass of living tissue it contains
biomass
there are more organisms and greater biomass at ____ trophic levels than at higher ones
lower
linear series of feeding relationships
food chain
Removal of a ______ species can significantly alter the structure of a community
keystone
example of keystone species
sea otter
predators at high trophic levels (sea otters) help organisms at low trophic levels (kelp) by limiting populations at intermediate trophic levels (sea urchins)
trophic cascade
Grass -> mouse -> snake -> hawk, this is an example of
food chain
feeding relationships have both _____ and ______ affects on organisms in the community
direct
indirect
following a disturbance communities may under go ____
succession
_________ shift carrying capacity
limiting factors
Severe disturbances can cause permanent changes to a community and initiate a predictable series of changes called
succession
occurs when there are no traces of the original community remaining, including vegetation and soil
primary succession
Occurs after a bare rock or sediment is exposed for the first time (lake dries up, glacial retreat)
primary succession
such as lichens are the first to colonize
pioneer species
occurs when a disturbance dramatically alters a community but does not completely destroy it
secondary succession
Common after disturbances such as fire, logging, or farming
secondary succession
succession that happens faster
secondary succession
________ succession occurs when an area fills with water for the first time
primary aquatic
Disturbances such as floods or excess nutrient runoff can lead to _______ succession
secondary aquatic
without ________ species introduced to a new area can become invasive
limiting factors
nonnative (exotic) organisms that spread widely in a community
invasive species
A lack of limiting factors such as predators, parasites, or competitors enables their population to grow unchecked
-ex. kudzu, nutria rats
invasive species
not all invasive species are harmful
ex. _______
honeybee
Ecologist think invasive species are the ___ greatest threat to natural systems and species
2nd
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