unit 8 Flashcards
how do organisms respond to the environment?
through behavioral and physiological mechanisms
stimulus
internal/external signal that causes response in organism
signaling behavior
communication can change the behavior of organisms and cause differences in reproductive success.
communication mechanisms
visual
audible
tactile
electrical
chemical signals
uses of communication mechanisms
indicate dominance
find food
establish territory
ensure reproductive success
innate behaviors
genetically controlled
learned behaviors
developed from exeriences
cooporative behaviors
Same species teamwork that inc fitness and survival of population.
examples of cooporative behaviors
aposemetism (discourage predation), scent markings by mammals
endotherms
use thermal energy generated by metabolism to maintain homeostatic body temperatures
endothermic mechanisms
change HR, fat storage, muscular contractions (shivering)
ectotherms
lack efficient internal mechanisms to regulate temp, so rely on behaviors
ectotherms mechanisms
moving in or out of the sun
there is a relationship between metabolic rate per unit of body mass and
size of multicellular organisms
metabolic rate
amount of energy to be expended by an animal over a specific amount of time
net gain in energy
energy storage/growth
net loss in energy
loss in mass and possibly deat
the smaller the organism the ___ metabolic rate
higher
reproduction strategies in response to energy availability
producing a lot of offspring at once
- less energy effecient
-common in unstable environments
producing few offspring at once
- more energy effecient
- more common in stable environments
changes in energy resources and producer level can affect
number and size of trophic levels
trophic level
position an organism occupies on a food chain
food chain
shows ONE path of energy
food webs
shows many transfers of energy between trophic levels (everything is connected)
inefficiency limits and population size ____ as you go up trophic levels
decrease
autotrophs
organisms that capture energy from physical or chemical sources in the environment, like the sun in photosynthesis
chemosynthetic organisms
capture energy from small inorganic molecules in the environment with or without oxygen
heterotrophs
capture energy present in carbon components produces by other organisms
metabolize carbs, lipids, proteins as energy sources through hydrolysis
less food available =
less energy, low repro, offspring survival decrease
more food available =
reproduction increase population increase
factors that affect population growth
age at reproductive maturity
number of offspring produces
reproduction frequency
offspring survivability
reproduction without constraints leads to
sharp increase in population growth
exponential growth occurs when
abundant resources + number of offspring in each generation incs
population density
how close individuals within a population live to each other
factor that affect population density
resource availability
abundance of food =
dense pop, high repro, limited space
density dependent factors
abiotic or biotic factors whose effect on the population depends on density
ex:
cometition for resources
disease
predation
density independent factors
abiotic or biotic factor that affect population size regardless of density
ex:
natural disasters
logistic growth model
describes population growth that initially starts slowly, immediately followed by exponential growth, and ends with relatively stable max growth
S curve
carrrying capacity
max # of individuals an environment can sustain
- density dependent and density independent factors can cause population ro reach carrying capacity
limiting factors will…
bring population size back down if it exceeds carrying capacity, fluctuations can naturally occur near carrying capacity.
ecosystem diversity is related to its ____ to changes in the environment
resilience
diversity may impact the…
organization of an ecosystem
- env can be stabilized w more diversity and less vulnterability to drastic changes
abiotic factors
climate, water, nutrient availability, light availability
biotic factors
producers and dominant predators
producers
many pop depend on them and they reduce erosion
dominant predators
keep prey pop in control and have diversitfied diets
keystone species are disproportion relative to their ____
abundance
keystone species
species that community structure depends on, tend to have small population (over depletes resources)
when a keystone species is removed…
community COLLLAPSES
evolution is characterized by change in…
genetic makeup over time
adaptations…
inc biodiversity, causes pop to evolve, and can lead to speciation
invasive species affect
ecosystem dynamics, availability of resources, ecological changes
invasive species
not native to specific area and harms the community
invasive species exploit new niches
niche is free of predators or competitors
outcompetes other organisms for resources
population increases unchecked
human activity that accelerates change on local and global levels
urbanization, deforestation, erosion, extinction, pollution,climate change
things that accelerate evolution
repro isolation, new niches, change in selective advantage
biographical studies illustrate the changes in
species distribution and biomes
geological and meterological events…
caused 5 major extinctions
el nino
phenomenon of changing in temperature of pacific ocean, impacts microscopic organisms (cytoplankton
energy is lost from the system as
heat!
10 percent law
when organisms are consumed approximately 10 percent of their energy is available to the next trophic level.
limited energy leads organisms to
budget their energy~
