10/4 quiz Flashcards
physiological ecology
adaptations to the physical environment
organisms have mechanisms to…
perform well in a limited range of conditions
compensate for a certain range of variation in conditions
examples of abiotic factors
temperature, water availability, salinity
types of environmental changes
predictable (seasonal, daily, tidal, etc.) or unpredictable (hurricanes, fire, etc.)
environmental variation serve as a significant challenge to an organism’s ___
fitness
levels of tolerance
variation in environmental conditions had different consequences for different processes (reproduction, growth, survival)
successful reproduction/population maintenance occurs at ___ ranges than survival and growth
narrower
environmental tolerances determine the ___ ___ of organisms
geographic distribution
ex: most herps (reptiles and amphibians) avoid low temperatures
acclimatization
reversible (within the individual’s lifetime) shift in physiological tolerances of an individual
examples of acclimatization
thicker fur in winter, smaller leaves during dry season, humans in high altitudes
adaptations
genetically determined characteristic that enhances an individual’s fitness in its environment
secondary definition of adaptation
evolutionary process that allows organisms to become better suited to their environment
disclaimers about adaptations!
they may challenge other adaptations
they have evolutionary trade-offs
example of different populations adapting to the same conditions in different ways
humans in high altitudes
andes: high RBC concentration and larger lung volume
tibet: normal RBC conc. and elevated breathing rate
categories of responses
adaptive avoidance and adaptive tolerance
types of adaptive avoidance
behavioral (migration) and metabolic
examples of metabolic avoidance
metabolic rate depression, hibernation, and estivation
types of adaptive tolerance
behavioral, morphological, physiological, and biochemical
pros of migration
avoid harsh conditions and expand resource base
cons of migration
energetic cost and high risk of mortality
what determines migration?
seasons -> its seasonal movement to/from a region
external stimuli serve as cues
when is migration most advantageous?
when abiotic challenges are seasonal and predictable
example of organism that migrates
monarch butterflies - avoid low temperatures
wildebeest - avoid drought
avoidance
avoiding an environmental change
can occur seasonally or even daily between microhabitats/environments
example of organism using avoidance adaptation
desert iguana - regulates body temp by moving microhabitats
types of metabolic avoidance
dormancy, metabolic arrest, torpor, hibernation, or estivation
example of organism using dormancy
coconut seeds when surrounded by harsh, salty water
example of organism using metabolic arrest
brine shrimp - lose most of their bodily water content and rehydrate when water is available in their environment
torpor
short-term reduction in metabolic rate (overnight)
for low temps or food deficiency
hibernation
prolonged torpor (weeks/months)
estivation
reduction in metabolic rate due to heat or drought
why is temperature important to survival?
metabolism and other bodily systems are dependent on enzymes, which are temp sensitive
high temp -> denature
low temp -> inactive
what can happen to lipid membranes at low temps?
solidify
things can’t be transported in/out of cell
what happens if a cell freezes?
can be punctures by ice crystals
ex: frostbite
two ways of dealing with temperature variation
endotherm or ectotherm
what is an endotherm?
generate heat through metabolism
requires higher metabolic rate and energy demands
mammals and birds
ectotherms
regulate body temp through behavior, not metabolism
lower metabolic rate and energy demands
reptiles, amphibians, invertebrates
what are behavioral changes ectotherms can use?
basking, changes in posture, and changes in orientation
what are two standards of temperature for organisms?
homeotherms or poikilotherms
what is a homeotherm?
organisms that keep their body temp relatively constant
most endotherms, few ectotherms
example of homeotherm
many marine fish - live in water that stays at a constant temp
what is a poikilotherm?
organisms who have varying body temps
most, but not all, ectotherms
intracellular freezing is always ___
lethal
cell rupture
how can organisms deal with low temps?
metabolism (endo) or insulation (fur/blubber)
how do freeze tolerant species work?
have anti-freeze like compounds to lower body’s freezing point
body can cool to -20 C w/o freezing
examples of anti-freeze compounds
glycerol and glycoproteins
examples of freeze-tolerant species
Antarctic fish, some insects, painted turtles
extracellular freezing is…
challenging but possible
what controls the balance between and organism and it’s environment’s salt concentration?
osmosis
animal mechanism to control water/salt concentration
urine concentration or salt glands
what do salt glands allow animals to do?
drink sea water
species are limited by ___ ___ and ___
physical factors and resources
each species has __ and ___ ___ limits
upper and lower tolerance
what determines species distributions?
physical environment, biotic interactions, and evolutionary history
how can the physical environment determine a species’ distribution?
tolerance limits
examples of biotic interactions that can influence species distributions
food, predators, competition, parasites, and diseases
example of evolutionary history impact species distribution
polar bears being in north pole but not antarctica
can physically survive there, but won’t migrate and didn’t evolve there
what are climate patterns a result of?
shape (latitude) and tilt of earth, atmospheric circulation cells, oceanic currents, proximity to oceans and mountain ranges
when we discuss climate, we will consider…
temperature, precipitation, averages, and variation
why does the equator experience hot/wet climate?
gets focused sunlight
“angle of incidence of sunlight”
what causes seasonal variation?
spherical shape + tilt + orbit
what is the solar equator?
where the sun hits the earth’s surface perpendicularly, changes with earth’s rotation
what results from tropics getting more direct sunlight year-round?
higher average annual temperature
less seasonality in temperature
what does the northern hemisphere experience when being tilted towards the sun?
more direct sunlight
longer days
describe how hadley cells of air circulation work
at equator: low pressure, warm, wet air rises to create rainfall, then moves north/south and cools, colder, higher pressure, dry air sinks, warms back up and picks up moisture in regions it falls on
what do hadley cells result in?
general tendency for tropical and subtropical rainforests at equator and deserts 30 degrees in latitude from there
what are the names of all three air circulation cells in each hemisphere?
hadley, ferrell, and polar
areas with the most energy incidence get the most ___
rainfall
what determines wet and dry seasons in the tropics?
position of the solar equator
at equator, there are ___ wet and dry seasons
2
rain belt passes twice a year moving north and south
between tropics and temperate areas, which has the most temperature seasonality?
temperate
between tropics and temperate areas, which has the most precipitation seasonality?
tropics
global climate can be explained by:
spherical shape and tilt of the earth and its orbit around the sun
temperate zones experience greater temperature in ___
temperature
due to tilting and orbit
tropics experience greater seasonality in ___
precipitation
due to rain belt oscillation
how does proximity to oceans impact the northern hemisphere?
less rainfall - less open water to get water from (than southern hem.)
higher temperature variation - less moderating effect of oceans
what does it mean that water has a high heat capacity?
a large amount of heat is necessary to change its temperature
as you get further from oceans, you observe…
less rainfall in interior than coast
less temperature variation along coasts
even regionally!
how do mountain ranges impact climate?
rain shadow effect
rain shadow effect
how one side of the mountain will have moisture and the other side will be significantly drier
example of distribution of one species limiting the distribution of another
tsetse flies limiting cattle due to disease they spread
what are examples of physical barriers that limit continental and global species distributions?
oceans, mountains, river
what is a more recent way organisms have found to overcome physical barriers to distribution?
human movement
how has evolutionary history impacted species distributions?
geological history, historical shifts in climate, and phylogenetic history
what are examples of geological history?
continental drift and glaciation
what is an example of historical shifts in climate?
range breaks due to historical local extinctions
what are examples of phylogenetic history?
phylogenetic conservatism of species’ range limits
divergence of the range limits
what is the great american interchange
north america was part of laurasia and south america was part of godwana
sa mammals colonized na and vice versa occurred
biome
a biological community defined by its dominant plant forms/physical growth structure
what’s the difference between an ecosystem and a biome?
can have the same basic growth forms (same biome) but consist of different species (different ecosystems)
why are biomes centered around plants?
they provide overall character of an area
are primary producers (basis of food web)
have a lot of exposure to environments and no means of controlling their internal environment (compared to animals)
what determines the distribution of plants?
climate, soil and disturbances
what are examples of aspects of CLIMATE that can influence plant distribution?
temperature, precipitation, and seasonality
what are aspects of SOIL that determine plant distribution?
permeability and nutrient composition
what are examples of DISTURBANCES that influence plant distribution?
fire, herbivores, and anthropogenic effects
why do temperate zones experience greater seasonality in ___?
temperature
earth’s tilt and orbit
why do tropic zones experience greater seasonality in ___?
precipitation
rain belt oscillations
what makes grasses different from most other plants?
grasses grow from their base, underground
most other plants grow from tips
grasses are better protected from disturbances
better adapted to warm, dry conditions due to their photosynthetic pathway
what does a Whittaker climate diagram do?
define biomes by their average temperature and annual precipitation
what is the primary problem with Whittaker climate diagrams?
they disregard seasonality, fires, and soil conditions because they are so big picture
good for a general understanding though
despite being discrete entities on the Whittaker climate diagram, the different biomes have…
a lot of continuous variability within them
what are on the axes of Whittaker climate diagrams?
x = average temp (backwards orientation!)
y = annual precipitation
things to note about walter climate diagrams
absolute temperature and precipitation
10 degrees to 20 mm relationship btwn temperature and precipitation
number of months with average minimum above freezing are highlighted on x-axis
what does a walter climate diagram recognize?
importance of variation in climate throughout the year
when can plants grow in a walter climate diagram?
when precipitation line is above temperature line and temperature line is over 0C
what can we identify from WCD?
general temperature and presence of seasonality
general precipitation and presence of seasonality
droughts
presence and length of growth season
hemispherical geography
sclerophyllous scrub growth form
tough, leathery leaves
sclerophyllous shrub environment
temperature and precipitation seasonality, warm/cool
deciduous tree growth form
they drop their leaves in cold or dry periods
deciduous tree environment
moist, seasonally warm/cool on fertile soils or warm, seasonally wet/dry
grasses, sedges growth form
grow from the base of their leaves
grasses, sedges environment
moist, temperature seasonality, with fire
cacti and shrub growth form
succulent stems/leaves, water storage tissues
cacti and shrub environment
dry, seasonally hot/cool
evergreen broad-leaved trees growth form
photosynthesis year-round
evergreen broad-leaved trees environment
wet, warm year-round
needle-leaved evergreen trees growth form
photosynthesis year-round
needle-leaved evergreen trees environment
moist, seasonally warm/cool or cool cold in infertile soils
forbs growth form
broad-leaved herbaceous (non-woody) plants
forbs environment
seasonally cool/cold
what are the three main types of biomes?
tropical, temperate, and boreal
what are characteristics of tropical biomes?
within about 20-30 degrees of equator
temperatures vary more within a single day than from month to month
seasonality of rainfall
plants are not freeze-tolerant
what are the types of tropical biomes
tropical rainforests, savannas, and deserts
what characterizes tropical rainforests?
broad-leaved evergreen trees
continuous canopies with multiple understory layers
low temperature seasonality, high rainfall (1 or 2 peaks)
tropical rainforests have high ___ but poor ___
biodiversity - 7% of land surface, 75% of known species
soils - quick and continuous decomposition of plant litter due to temp and humidity, clay soils don’t hold nutrients well
what are tropical rainforests vulnerable to?
disturbances like logging/burning (removes nutrients), rain leaching nutrients away, soil erosion
stratification
when a habitat has vertical layering
1: emergent trees
2: canopy
3: understory
4: forest floor
plus lianas and epiphytes (plants that grow on other plants)
what is the main difference between the climate of savannas and rainforests?
seasonality of precipitation is the same but now temp can drop lower
there are also droughts in savannas and not rainforests
what do animals characteristically do in savannas?
migrate due to seasonality of precipitation
what are savannas characterized by?
frequent fires (from lightning)
usually grasslands
few trees because of the fires and existing species are fire-adaptive and many are endemic (only in that place) - some plants even need fire to germinate
types of deserts
hadley cell, rain shadow, continental interior
what are deserts characterized by?
droughts and minimal plant growth
never a month in Walter climate diagrams that supports plant growth (drought or freezing)
sustained periods of high temps and low water availability
plants grow quickly when rainfall does occur
what type of plants grow in deserts?
succulents, shrubs, and grasses
what are examples of temperate biomes?
grasslands, shrublands, and deciduous forests
- some part of their Walter climate diagram will always be below freesing
what is the primary differentiation between temperate biomes?
totals amounts and seasonal patterns of precipitation
why is frost important?
frost-free season is “growing” season
temperate grasslands climate
too dry for trees, but wet enough for grasses (not desert dry)
most precipitation occurs during non-freezing, growing seasons
temperate grasslands characteristics
maintained by drought, fires, and grazing
large populations of big roaming herbivores
dominated by grasses and herbaceous vegetation
high productivity and fertile soils
example of temperate grassland
great plains in US
mediterranean shrublands climate
mild, rainy winter and hot, drought summers
asynchrony between summer growing season with low rainfall and winter rains
won’t necessarily get below freezing
mediterranean shrubland characteristics
regular fire disturbances
fire-adaptive plants, but no cacti
sun and warm temp year round
open canopy of short trees and thick, evergreen shrubs
sclerophyllous vegetation
high species diversity
temperate deciduous forest climate
50-90 mm precipitation each month
mix of temps above and below freezing
enough rainfall to support tree growth
temperate deciduous forests characteristics
soils are fertile enough to support trees after they lose their leaves
lose leaves in extended periods of freezing (bc why maintain leaves when they aren’t serving a purpose?)
species diversity lower than tropical forests
fire not a major factor
this is where we live!
what plants usually grow in temperature deciduous forests?
oak, maple, beech trees plus shrubs and forbs
examples of boreal biomes
boreal forests and tundra
what is a characteristic trait of boreal biomes?
soils with permafrost (some portion is always frozen) -> slow decomposition (bc its so cold) leading to excess of organic matter and poor nutrients
plants can’t have deep roots
boreal forests climate
long winters and short growing seasons
high temperature seasonality
cold and dry
subfreezing temps up to 6 months
boreal forests characteristics
largest biome - 1/3 of earth’s forested land
mostly coniferous trees
cold, wet and permafrost soil
summer droughts promote fires (think canada)
tundra climate
cold - very short growing season
permafrost
soil - poor; low rates of decomposition
tundra characteristics
low shrubs, grasses, lichens, and mosses
continuous light for 1-2 months in summer
low precipitation, permafrost prevents soil drainage
very low temps most of the year
importance of mountains when studying biomes
create elevation based climatic gradients that change rapidly
altitude changes serve like latitudinal changes, can keep geography relatively constant
how much do temperatures increase for every 1000m increase in elevation?
6.4 C
what are examples of population demography factors?
size, age structure, and distribution
example of demography used in conversative biology
saving sea turtles from extinction due to fishing issues
able to use demography to better target high mortality rate time periods
life span
maximum number of years an individual can potentially live
life expectancy
expectation of life at a certain age
affected by the probability of dying at different ages
