Exam Three: Learning Objectives Flashcards
(197 cards)
Define life history
schedule of an organism’s growth, development, reproduction, and survival
Life history traits include __ strategies and __ of key life events; as well as __ adaptations shaped by __
reproductive; timing
reproductive; selection
List eight life history traits
age at maturity
size at maturity
number of offspring
offspring size
parental care of young
life span
reproductive span
semel- v iteroparity
Define fecundity
number of gametes, seeds or propagules produced
Species with higher fecundity tend to lay __ eggs; describe the trade off
small
trade off: can lay many eggs or large eggs, but not many large eggs
Define the principle of allocation
given limited access to energy, if an organism allocates resources to one function (e.g., growth, maintenance), it reduces the amount of energy available to other functions (e.g., reproduction)
Describe the proportiaonality between female size and the number of eggs laid; and the number of eggs compared to the number of eggs
female size directly proportional with number of eggs - large female = more eggs
indirect relationship between number of eggs and egg diameter, smaller egg diameter = more eggs laid
Gene flow is inferred from __ __
allele frequency
Define a locus
position on a chromosome
What is a polymorphic locus?
site of a gene with many alleles
We can use allele frequency similarity between populations to make inferences about __ and _ __ among them
dispersal
gene flow
Describe the relationship between allele frequencies at a locus and dispersal between populations
if several populations of the same species have similar allele frequencies at a locus, then there is probably a lot of dispersal (gene flow) among the populations
Species producing larger seeds produce __ seeds
fewer
The mode of seed dispersal is dependent on __ __. This is important because dispersal is critical for a population to establish its __
seed size
range
Describe the tradeoff between seed size and number
allocating more energy per offspring means a parent organism will produce fewer offspring
in plants, to see the trade off between offspring size and number, you can compare vastly different taxa
You can also compare closely related species, and different populations of the same species
mass of seeds is inversely proportional to number of seeds
Discuss the evolutionary implications of life history in terms of allele frequency and darter populations
allele frequencies were similar among some species; gene flow among populations was thus probably high for these species
allele frequencies were different among populations of other species; gene flow among populations was probably low for these other species
Gene flow is more common among species with a smaller egg size - shows inverse linear relationship
Discuss the different life history strategies of grasses and herbs and trees
seedling growth was greater for species that produce larger seeds
in grasses, bigger seedlings had a greater chance of surviving past the seedling stage
for trees, larger seeds germinated earlier in the spring, before the overhead trees put out their leaves and shaded the new plants
European magpies tend to lay clutches with 7 eggs, which results in about 3-4 successfully fledged chicks, discuss what happens if eggs are experimentally removed or added
fewer eggs = fewer fledged chicks
more eggs = less well-nourished chicks = fewer fledglings
Why is clutch size a heritable trait?
clutch size of seven yields greatest fitness, and is heritable, then clutch size of 7 becomes common in the population
Describe the hypothesis: drought is an evolutionary force that selects for dry-adapted life history strategies
collect seeds from naturally wet and naturally dry sites before and after drought (4 populations), rear them and determine when they flower
seeds from dry site flowered around 41 days
seeds from a wet site flowered around 59 days with large phenotypic variability
in a post-drought population, the wet site population will look more like a dry site than a wet site, as the evolutionary conditions act as natural selection
Species with delayed reproduction generally have __ adult survival
higher
High allocation to reproduction is associated with high __
mortality
T/F: there can be no variation among populations in terms of evolutionary traits
false, many species exhibit different survival curves
As allocation to reproduction increases, relative rates of adult _ decline
survival