Anthro 2B Final Study Guide
Comprehensive Questions (Frequently
Tested) with Verified Answers Graded A+
Macro-Evolution - Answer: - evolution on a large scale, this leads to the formation of new
species
Micro-Evolution - Answer: - evolutionary change within a species or small group of organisms,
especially over a short period.
- Changes in gene frequencies over time.
Speciation - Answer: - the process by which one species splits into two or more species
- macroevolutionary event
- will always involve reproductive isolating mechanisms
Reproductive Isolating Mechanisms
(Extrinsic, Intrinsic, Prezygotic, Postzygotic) - Answer: - Extrinsic: Factors producing geographic
isolation.
- This includes spatially separating some population. (movement of tectonic plates or climate
change alters environment so populations are separated)
- Intrinsic: Includes Prezygotic and Postzygotic mechanisms
- Prezygotic: prevention of a zygote from being formed. This includes seasonal issues (some
trees pollinate in the winter while others pollinate in spring) or the environment (toads wanting
to breed in running vs still water)
- Postzygotic: The zygote is formed but might have some problems, such as differences in
genetic instructions from parents that can result in a spontaneous abortion. Or when it's born,
the offspring is too sick and has a weak, nonfunctioning system and dies.
,Natural Selection and Population Variability - Answer: - The rate of evolutionary change is
directly proportional to the degree of variability in the population
- We are constantly tapping into the genetics variants of all living things for our own benefit.
Having genetic variation is important because it gives us options to continue changing in the
world.
- Corollary: The belief that the fate of all evolutionary lineages is extinction. 99.99999% of all life
forms that have ever lived on this Earth are gone without leaving descendant lineages
Anagenesis - Answer: - Slow, gradual, incremental changes from generation to generation.
Through long time frames.
- We could estimate that the end product compared to its ancestor are unable to breed because
of their differences after so many years.
Cladogenesis - Answer: - A set of population that splits because of some isolating mechanism
which develops over time.
- Speciation is an example of cladogenesis. (a species branches off into two or more descendant
species)
Phyletic Gradualism - Answer: - Species evolve by the accumulation of many small changes over
a long time period
- Evolution happens through slow, incremental, gradual changes that slowly builds from
generation to generation.
- Emphasizes anagenesis (both anagenesis and cladogenesis happens, but it EMPHASIZES
anagenesis)
- SLOW GRADUAL CHANGE
Punctuated Equilibrium - Answer: - We have long periods of stasis that hardly change and then
all of a sudden, something triggers change to occur and a species will rapidly change, following
another period of stasis and another burst of rapid changes.
- Emphasizes cladogenesis
, - most change during speciation events (macroevolution)
Adaptive Radiation - Answer: - Rapid expansion and diversification of a group of organisms as
they adapt to newly available ecological space
- Series of cladogenic events
- Rapid speciation to adapt to environmental changes.
- Adaptive radiation occurs when there's any changes that open up new potential habitats to a
group of organisms. For example, species w high adaptive potential invades a new location
(such as finches in the Galapagos). Or, a mutation will produce a huge major adaptive shift.
(Amphibians evolving from staying in the water to laying eggs on land to expand their resources,
like food sources on land (insects and plants). This evolves into reptiles).
Generalized - Answer: - Able to exploit a wide range of ecological space (a broadly defined eco-
niche)
- A generalized species can do well in a number of different ecosystems. They can eat many
different kinds of foods and can adapt to environment fairly easily.
- Not very good at doing one particular, but can do many things.
- Generalized species have a greater Adaptive Potential than Specialized ones do.
Specialized - Answer: - Requires very specific living conditions. Specialized in a narrowly defined
eco-niche.
- A species gets really good at living at one certain environment. They eat one type of food and
they get really good at living in a specific habitat.
- Overspecialization leads to extinction.
Evolutionary Homology - Answer: - Similarities between organisms due to a common ancestry.
- If and only if the last common ancestor had that particular trait.
- If the two lines speciated, then that means they just kept that particular trait that their
ancestor had.
Comprehensive Questions (Frequently
Tested) with Verified Answers Graded A+
Macro-Evolution - Answer: - evolution on a large scale, this leads to the formation of new
species
Micro-Evolution - Answer: - evolutionary change within a species or small group of organisms,
especially over a short period.
- Changes in gene frequencies over time.
Speciation - Answer: - the process by which one species splits into two or more species
- macroevolutionary event
- will always involve reproductive isolating mechanisms
Reproductive Isolating Mechanisms
(Extrinsic, Intrinsic, Prezygotic, Postzygotic) - Answer: - Extrinsic: Factors producing geographic
isolation.
- This includes spatially separating some population. (movement of tectonic plates or climate
change alters environment so populations are separated)
- Intrinsic: Includes Prezygotic and Postzygotic mechanisms
- Prezygotic: prevention of a zygote from being formed. This includes seasonal issues (some
trees pollinate in the winter while others pollinate in spring) or the environment (toads wanting
to breed in running vs still water)
- Postzygotic: The zygote is formed but might have some problems, such as differences in
genetic instructions from parents that can result in a spontaneous abortion. Or when it's born,
the offspring is too sick and has a weak, nonfunctioning system and dies.
,Natural Selection and Population Variability - Answer: - The rate of evolutionary change is
directly proportional to the degree of variability in the population
- We are constantly tapping into the genetics variants of all living things for our own benefit.
Having genetic variation is important because it gives us options to continue changing in the
world.
- Corollary: The belief that the fate of all evolutionary lineages is extinction. 99.99999% of all life
forms that have ever lived on this Earth are gone without leaving descendant lineages
Anagenesis - Answer: - Slow, gradual, incremental changes from generation to generation.
Through long time frames.
- We could estimate that the end product compared to its ancestor are unable to breed because
of their differences after so many years.
Cladogenesis - Answer: - A set of population that splits because of some isolating mechanism
which develops over time.
- Speciation is an example of cladogenesis. (a species branches off into two or more descendant
species)
Phyletic Gradualism - Answer: - Species evolve by the accumulation of many small changes over
a long time period
- Evolution happens through slow, incremental, gradual changes that slowly builds from
generation to generation.
- Emphasizes anagenesis (both anagenesis and cladogenesis happens, but it EMPHASIZES
anagenesis)
- SLOW GRADUAL CHANGE
Punctuated Equilibrium - Answer: - We have long periods of stasis that hardly change and then
all of a sudden, something triggers change to occur and a species will rapidly change, following
another period of stasis and another burst of rapid changes.
- Emphasizes cladogenesis
, - most change during speciation events (macroevolution)
Adaptive Radiation - Answer: - Rapid expansion and diversification of a group of organisms as
they adapt to newly available ecological space
- Series of cladogenic events
- Rapid speciation to adapt to environmental changes.
- Adaptive radiation occurs when there's any changes that open up new potential habitats to a
group of organisms. For example, species w high adaptive potential invades a new location
(such as finches in the Galapagos). Or, a mutation will produce a huge major adaptive shift.
(Amphibians evolving from staying in the water to laying eggs on land to expand their resources,
like food sources on land (insects and plants). This evolves into reptiles).
Generalized - Answer: - Able to exploit a wide range of ecological space (a broadly defined eco-
niche)
- A generalized species can do well in a number of different ecosystems. They can eat many
different kinds of foods and can adapt to environment fairly easily.
- Not very good at doing one particular, but can do many things.
- Generalized species have a greater Adaptive Potential than Specialized ones do.
Specialized - Answer: - Requires very specific living conditions. Specialized in a narrowly defined
eco-niche.
- A species gets really good at living at one certain environment. They eat one type of food and
they get really good at living in a specific habitat.
- Overspecialization leads to extinction.
Evolutionary Homology - Answer: - Similarities between organisms due to a common ancestry.
- If and only if the last common ancestor had that particular trait.
- If the two lines speciated, then that means they just kept that particular trait that their
ancestor had.
