Test 2 Flashcards
What is the definition of Life History?
The lifetime pattern of GROWTH, REPRODUCTION, and DEVELOPMENT.
Describe the cost of reproduction for three-spined sticklebacks
Some males have red throats, which increases their reproduction, but also makes them more visible to predators
Describe the different modes of reproduction (2)
Sexual: Genetic diversity, more choices
Asexual: Stolons, rhizomes, budding, parthenogenesis, easy mating
Describe the different mating strategies and examples of each (2)
Monogamy: Common in birds (raise young together) and in mammals that are territorial with a strong social structure
Polygamy: Individual with many mates does not care for offspring, occurs when resources are unevenly distributed. Either Polygyny (>1 female per male) or Polyandry (>1 male per female)
Describe Polygyny, Polyandry, and Promiscuity
Polygyny: Male bonds with 2+ Females, # depends on sexual receptivity length
Polyandry: Female bonds with 2+ Males, occurs in unstable environment (need more help with eggs)
Promiscuity: No pair bonding, occurs in zoos and populations with unbalanced gender ratios
What is the definition of iteroparous? Describe its effects
Reproduce many times. Early reproduction leads to lower fecundity per episode and reduced survivorship, later reproduction leads to higher fecundity and survivorship
What is the definition of semelparous? Describe its effects
Reproduce only once (occurs in insects, plants, fish). Initial investment only to growth, development, and energy storage. One large reproductive effort, then death
What is the definition of parthenogenesis?
Females produce all female offspring without fertilization
What are the types of hermaphrodites? What about plants?
Sequential hermaphrodites are triggered by size or a change in the sex ratio of the population (as in parrotfish F→M)
Simultaneous hermaphrodites always possess both male and female reproductive structures
Plants can be dioecious (separate male and female individuals), hermaphroditic (bisexual flowers), or monoecious (male and female flowers)
Describe the tradeoff between future survival (of the parent) and parental care
Probability of future survival can be reduced by feeding and protection of young
Female red deer in Scotland that reared a calf to weaning age (milk hinds) had higher mortality than those that did not (yeld hinds)
Describe the environment that leads to a large number of offspring with little investment
Unpredictable environments or areas where parental care is difficult
Describe the difference between the spotted salamander and the redback salamander
The spotted salamander has many eggs with no parental care while the redback salamander lays a few eggs that are guarded
Describe the tradeoff between body mass of an individual and its absolute fecundity. What are some examples?
More body mass more fecundity.
Between three species of crab, the ones that waited to have their first brood had more eggs per brood
Lifetime reproductive success of European red squirrel positively correlates with body weight in first adult winter
Describe the tradeoff between fecundity and survival
Using the example of the European Kestrels:
When the brood size of European kestrels was artificially increased, both parents hunted more, adult survival declined, food intake per chick declined, nestling growth rate was reduced, and nestling mortality increased
Describe the occurrence of asynchronous hatching. In what animals does it occur?
Occurs in some species of raptors, herons, and egrets that live in unstable environments
Egg laying is staggered over a week, last egg hatched has a big disadvantage
Describe the difference between altricial and precocial
Altricial: Young are born helpless
Precocial: Young are born at a more advanced state of development
Describe how sexual selection occurs in species with or without resources being a factor
Without resources
Exaggerated characteristics or sexual displays
With resources
Intrasexual selection involves M-M competition
Define Lek Species and describe the different types
Lek Species have gene-only female choice. The males gather to engage in competitive displays to woo females.
Female Choice → Females pick mating territory
Hotspot → Males establish a lek where many female’s range overlapped
Hotshot → Mala/mate interactions, 1 male has >90% of the copulation, females pick ground
Define r-selected vs. k-selected species. Which are spotted salamanders and which are redback salamanders?
Growth, survival curve, cause of mortality, parental care, # of offspring, age at first reproduction, level of intraspecific competition
R-Selected
Exponential growth, density independent mortality, type 2 or 3 survival curve, low intraspecific competition
Low age at maturity with rapid growth, large litter or clutch size, reproduction on quantity with little to no parental care
Example: Spotted salamanders
K-Selected
Constant growth near carrying capacity, density-dependent mortality, type I survival curve, intense intraspecific competition
High age at maturity with slow growth, small litter or clutch size, reproduction on quality with substantial parental care
Example: Redback Salamanders
Name and describe the two categories of regulators of population dynamics
Density-dependent
Disease, competition, predation
Density-independent
Floods/Droughts, fires, storms, irregular climate
Name and describe the two types of intraspecific competition
Scramble - growth/reproduction depressed equally
Contest - some claim enough for themselves while denying others
What are the outcomes of intraspecific competition?
Growth retardation -Delayed development Growth reduction -Not growing to full size Increased mortality Reduced reproduction/fecundity
Describe self-thinning
When the population density increases, body mass decreases. When density lowers again due to deaths and reduced population size, body mass will increase again.
Lots of individuals will die during high density periods, but the body mass will increase in survivors
Describe the Allee effect
After the population size is reduced past a certain level, it becomes harder to find mates, and the growth rate decreases
Define Home Range vs Territory. How does territory change with population density?
Home Range: The area that an animal normally uses over the course of a year
Territory: Smaller than home range, well-protected
-Increased population density results in increased competition and smaller territory size
-The reduction in territory size lowered fecundity
Define PVA & MVP. What are the factors involved in PVA?
MVP or Minimum Viable Population: The number of individuals necessary to ensure the population’s existence over a stated period of time (such as 50/60 generations)
PVA or Population Viability Analysis: Estimation of MVP based on genetic factors, life history, previous fluctuations in population size, environmental variability, and more.
Define MDA
The area requirement per individual, involves size of home range and carrying capacity
It is the area of suitable habitat necessary for maintaining a MVP
How is MVP correlated with population growth rate
MVP is negatively correlated with growth rate
Describe the physiological mechanisms/responses of intraspecific competition
The increased crowding and social contact that occurs in high density populations causes stress that triggers hormonal changes that can suppress growth, curtial reproductive functions, and delay sexual activity. They may also suppress the immune system and break down while blood cells.
