Chapter 12 Life Histories Flashcards
A scientist studying the life history of a particular species would ask which of the following questions?
What are the trade-offs for producing either many small offspring or several large offspring?
What are the factors that influence age at first reproduction?
One of the biggest trade-offs in reproduction for many organisms is ______.
the number of offspring versus the size of the offspring
If an organism produces many offspring, ______.
the offspring will be small because of limited energy resources
Clutch size in fish can range from ______. (book)
one to 600 million
The number of eggs or seeds produced by an organism is known as ______
fecundity
A scientist investigating the environmental factors that determine the age at first reproduction would be studying ______.
life history
Darters are an ideal organism for studying gene flow among populations because there are ______.
many species that live in similar habitats
Why can’t an organism produce many large offspring?
Energy and resources are limited.
The trade-off between offspring size and number in darters is the fish that produce ______.
larger eggs produce fewer eggs
If an organism produces few larger offspring, the ______.
parents will typically invest more time and energy into each individual
Which group of animals shows the most variation in life history traits?
fish
A polymorphic locus ______
has two or more alleles
An organism with high fecundity would ______.
produce a large number of eggs or seeds
High levels of gene flow would most likely lead to ______.
genetically similar populations
What are the characteristics of darters that make them an ideal organism for studying gene flow?
Darters vary greatly in their life history characteristics.
Darters live in similar habitats and also have similar anatomy.
Darters are a taxonomically diverse group.
The findings of Turner and Trexler found that larger darters produce ______. (book)
a larger number of eggs
Darters that produced larger eggs had ______.
lower rates of gene flow between populations
When different alleles are found in a population that synthesizes different allozymes, this is known as a ______.
polymorphic locus
The smallest seeds known are produced by ______. (book)
orchids
Restricted gene flow between populations would most likely lead to ______.
genetic differences between populations
Plants that produce many seeds have seeds that are ______.
smaller
Populations of darters with higher rates of gene flow typically ______.
produce many smaller eggs
Determining mechanisms that select for seed size in plants is difficult due to ______.
the varied growth forms of plants
The largest seeds known are produced by ______.
coconut palms
Woody plants and vines produce ______.
larger seeds than graminoids
The sand spur, often found at sandy beaches, has barbs that latch onto fur or skin. This plant’s mode of dispersal would best be described as ______.
adhesion-adapted
Comparing epiphytes to trees to determine the mechanisms driving the evolution of seed size is difficult because of ______.
the various growth forms of plants
Typically graminoids produce ______.
the smallest seeds
After hiking in the woods, you discover a seed with a barb that latched onto your pants. This plant would best be classified as ______.
adhesion-adapted
To attract birds and other mammals, some seeds have a fleshy covering known as a(n) ______.
aril
What is an advantage of producing larger seeds?
The seedlings may have higher survivorship in times of environmental stress.
The process during which a seed begins to produce a small seedling is known as ______.
germination
Jacobsson and Eriksson created control plots by ______. (book)
not planting seeds in half of the plots
Seeds that are cached by birds or mammals are classified by Westoby, Leishman, and Lord as ______.
scatterhoarded
On average, plants that produce larger seeds ______.
have higher rates of recruitment
What is the advantage of producing smaller seeds?
A plant can produce greater numbers of seeds.
The process during which seeds begin to grow is known as ______
germination
Based on Seiwa’s and Kikuzawa’s studies, taller seedlings are produced from ______. (book)
larger seeds that have greater energy reserves
Jacobsson and Eriksson created control plots to determine ______.
how many of the plants would have germinated without being planted
Larger seed size may be important in environments ______.
where competition with plants already present is high
When adult survival is higher, individuals will ______.
delay reproduction and allocate less energy into reproduction
Seiwa’s and Kikuzawa’s studies on seed size demonstrated that ______. (book)
larger seeds produce larger seedlings
Shine and Charnov point out that a juvenile will allocate resources to growth ______.
and maintenance only
Jacobsson and Eriksson created control plots by ______.
not planting seeds in half of the plots
In species where adults have lower survival rates, individuals will ______.
allocate more energy into reproduction and begin to reproduce earlier
Based on Shine and Charnov’s studies, the benefits of delaying reproduction include ______.
higher reproductive rates
higher growth rates as juveniles
Shine and Charnov in 1992 indicate that only adults would allocate energy to ______.
reproduction
If individuals in a population face high mortality and therefore reduce the amount of energy they put into reproduction, the population will likely ______.
not persist for very long
A major factor in determining the age at first reproduction in lizards and snakes is ______.
adult mortality rates
Life history variation within a species is similar to interspecific variation in that ______.
the age at first reproduction is later where the adults experience lower mortality
Bertschy and Fox studied pumpkinseed sunfish to determine ______.
how adult survival influences the evolution of the age at reproduction
A population with high mortality would be expected to have a ______.
high reproductive effort
Bertschy and Fox estimated the ages of sunfish in Canadian lakes by ______.
measuring the length of the fish
Natural selection will favor allocating more resources to reproduction when ______.
adult survival is lower compared to juvenile survival
Lizard populations where adults live longer would be expected to ______.
delay maturation
The main purpose of Bertschy and Fox’s study was to explain ______.
how life history evolves variations within a species
True or false: Most species do not fit exactly into a specific life history classification.
true
The survival rate among adult sunfish in different populations ranged from ______.
one adult in five to two out of three
When adult mortality is low, natural selection will favor ______.
allocating fewer resources to reproduction at any given time
A population that is under r selection would ______.
be maximizing population growth rates
Life history strategies can be characterized based on which population characteristics? fstrat
survival
fecundity
age at first reproduction
Populations that are r selected are most likely to be found in ______.
environments with higher rates of disturbance
A population that is maintained near its carrying capacity is under ______ selection.
K
A population that ______ growth rate is under r selection.
maximizes
Organisms that are in predictable environments are often under ______.
k
Populations that are found in areas with high levels of disturbance are most likely under ______.
r selection
When adult mortality is low, natural selection will favor ______.
allocating fewer resources to reproduction at any given time
K selected populations maintain populations ______.
near the carrying capacity
A population that is under r selection would ______.
be maximizing population growth rates
A species whose population remains near the carrying capacity would ______.
favor efficient utilization of resources
Populations that are r selected are most likely to be found in ______.
environments with higher rates of disturbance
Species that maximize population growth rates are likely to have type ______ survivorship curves.
III
A population that ______ growth rate is under r selection.
maximizes
Organisms that are in predictable environments are often under ______.
K
Populations that are found in areas with high levels of disturbance are most likely under ______.
r selection
K selected species are likely to have ______.
high survival in early and middle life followed by a rapid decline later in life
a constant mortality rate for most of their life
K selected populations maintain populations ______.
near the carrying capacity
Development would be slowest in species ______.
maximizing competitive ability
A species whose population remains near the carrying capacity would ______.
favor efficient utilization of resources
K selected species are typically ______.
larger in body size and take longer to mature
The intrinsic rate of increase, rmax, is highest in species ______.
that are r selected
Salmon that reproduce one time in their life exhibit ______.
semelparity
According to J. P. Grime, the intensity of ______ and _____
are considered the most important selective forces on plants.
disturbance
stress
Plants classified as ruderal ______.
may depend on disturbance to reduce competition among other plants
Early reproduction and smaller body size are indicative of a(n) ______.
r selected species
An organism that has a single reproductive event is ______.
semelparous
Organisms often face many selective pressures for life histories. However, in plants, the two most important forces exerting selective pressure on plants are the ______.
intensity of stress
intensity of disturbance
Plants that are found in highly disturbed habitats are referred to as ______.
ruderals
Salmon that reproduce one time in their life exhibit ______.
semelparity
Any process that removes biomass from an ecosystem is known as a(n) ______
disturbance
To persist in a habitat that frequently experiences disturbances, most plants must be able to ______.
grow and reproduce before the next disturbance
Plants classified as ruderal ______.
may depend on disturbance to reduce competition among other plants
When plant growth is being limited, they are ______.
under stress
Examples of plant disturbances include ______. (book)
hurricanes
fires
floods
Stress on most plants is caused by ______.
too little light
low nutrients
too little water
A plant found in a disturbed habitat ______.
can grow and produce seeds rapidly
Environmental conditions that limit the growth of plants are known as ______
stress
High nutrients, too much sunlight, or high temperatures are examples of ______.
stress
Stress-tolerant plants are characterized as ______.
slow growing
typically evergreen
Stress-tolerant plants correspond to ______.
K selection
When plant growth is being limited, they are ______.
under stress
A plant that can live with high-stress conditions but low disturbance is ______.
stress-tolerant
A species that has early reproductive maturity combined with low fecundity and juvenile survival would fall into which kind of life history strategy?
opportunistic
Plants that are ruderal correspond to ______.
r selection
Environmental conditions that limit the growth of plants are known as _____
stress
One difference in fish that evolved the equilibrium strategy versus many K selected species is that ______.
some fish that are classified as “equilibrium” are small
Stress-tolerant plants are characterized as ______.
typically evergreen
slow growing
Select the three life history strategies for fish proposed by Winemiller and Rose.
equilibrium
periodic
opportunistic
Removing size and time effects allows scientists to ______.
make comparisons of life history strategies across different evolutionary phylogenies
The equation for the dimensionless variable for relative offspring size is ______.
I⁄m
The equilibrium strategy is similar to K selected species because they both have ______.
late reproductive maturity
low numbers of offspring
high juvenile survival
When analyzing life history strategies, what variables can be removed to help detect life history differences among evolutionary lineages?
the effects of size and time
When comparing the relative size of offspring in mammals, altricial birds, and lizards, ______.
lizards had the smallest relative offspring size
birds had the largest relative offspring size
each group differed in their relative offspring size
each group differed in their relative offspring size
dividing the mass of the offspring once it leaves the parent (l) by the mass of the adult at first reproduction (m)
The study of the timing of ecological events, especially in relation to climate and weather is called _______
phenology
When comparing the relative reproductive effort over a lifespan of diverse groups such as altricial birds, lizards, and mammals, ______.
mammals and lizards are very similar in their relative reproductive effort over a life time
Phenology is the study of the ______.
timing of ecological events, especially in relation to climate and weather
