Studied by 2 people
monophyletic groups
an evolutionary unit that includes an ancestor and all of its descendants, but no others
polyphyletic group
an unnatural group that does not include the most recent common ancestors
paraphyletic group
a group that includes an ancestral population and some of its descendants but not all descendants
homology
occurs when traits are similar due to common ancestry
homoplasy
occurs when traits are similar for reasons other than common ancestry
convergant evolution
independent evolution of similar traits in distantly relative organisms due to adaptation to similar environments and lifestyles; cause of homoplasy
How can you distinguish between homology and homoplasy?
genetics
morphology/structure
development
phylogeny
the evolutionary history of a group of organisms
Use traits to infer evolutionary relationships
How are phylogenic trees used?
phylogenetic tree
graphical summary of the evolutionary history of a group of organisms, visual model that shows the hypothesized evolutionary relationships among species or other taxa
synapomorphy
a shared, derived trait occurs in all the branches to the right of a black bar
polytomy
a node that depicts an ancestral branch dividing into three or more descendant branches
polytomy
a node that depicts an ancestral branch dividing into three or more descendant branches
Abiotic and biotic factors
What determines the geographic distribution and abundance of species?
climate
the prevailing weather conditions experienced in a region over relatively long periods of time - mean annual temperature (MAT), mean annual precipitation (MAP)
weather
the temperature, precipitation (rainfall and snowfall), wind speed and direction, humidity, cloud cover, and other physical conditions of Earth’s lower atmosphere at a specific place over a short period of time
Areas near the equator, receive high amount of solar radiation per unit area
What areas have the highest mean annual temperatures? Why?
Areas near the poles, receive low amount of solar radiation per unit area
What areas have the lowest mean annual temperatures? Why?
because the Earth is tilted on its N-S axis
Why does Earth experience seasons?
global air circulation cells
What affects precipitation?
What area has the highest mean annual precipitation? Why?
Areas near the equator, warm air rises and cools, dropping rain
What areas have intermediate mean annual precipitation? Why?
Areas near 60 degrees N and 60 degrees S, because they are in the middle of areas that receive high and low annual precipitation
What areas have the lowest mean annual precipitation? Why?
Areas near 30 degrees north and south and at the poles, because dense, dry air descends, warms and absorbs moisture
What is the coriolis effect?
the tendency for moving air or water to be deflected from a straight path, air and water move in a clockwise pattern in the Northern hemisphere and in a counterclockwise pattern in the Southern hemisphere
Examples of coriolis effect
westerlies; move from the SW to NE
NE tradewinds; move from the NE to SW
SE tradewinds; move from the SE to NW
Westerlies; move from the NW to SE
West, moisture-laden air blows onshore from Pacific Ocean, air rises over mountains and cools, rain falls
Which side of the Cascade Mountains has the highest mean annual precipitation? Why?
Effect of Oceans on climate
oceans have a moderating influence on temperature due to the high specific heat of water
oceans absorb heat in summer
cooler near the ocean
ocean release heat in winter
warmer near the ocean
In gyres, move clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere
How do massive ocean currents flow?
Sinking air and desert conditions
Areas at 30 degrees north and south latitude are most likely subjected to
Biomes
regions characterized by distinct abiotic characteristics
terrestrial biomes
regions characterized by distinct abiotic characteristics and dominant types of vegetation
What abiotic factors distinguish terrestrial biomes?
temperature
moisture
sunlight
wind
climate
mean annual temperature (MAT)
mean annual precipitation (MAP)
annual variation in temperature
annual variation in precipitation
Which biome has the least seasonal variation in temperature?
Tropical rain forest
Which biome has the greatest seasonal variation in temperature?
Boreal forest and tundra
Which biome has the highest mean annual precipitation?
Tropical rain forest
Tundra
Which biome has the lowest mean annual precipitation?
Tropical rain forest
Which biome has the highest diversity of reptiles, amphibians, and mammals?
Tundra
Which biome has the lowest diversity of reptiles, amphibians, and mammals?
Mutualism
Species interact in a way that confers fitness benefits to both species
Commensalism
One species benefits from the interaction and the other species is unaffected
Consumption
Interaction increases consumer’s fitness but decreases victim’s fitness; one species eats or absorbs nutrients from another
Examples of consumption
predation
Herbivory
Parasitism
Competition
Occurs when species use the same resources; results in lower fitness for both species
Symbiosis
Close, prolonged physical association between individuals of two species; living together
Examples of anti-predator defense mechanisms
cryptic coloration
Object resemblance
Schooling
Starle response
Toxins
Mimicry
Armor
Weapons (porcupine spines)
Alarm calls
