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Eco Evo Exam2(Fig.8)
Examples
Question | Answer |
---|---|
The schedule of an organism's life begins as an embryo. At all stages, species experience a characteristic amount of growth and some probability of surviving to the next stage. These stages are called...? | Life history traits |
The Canada thistle is an example of what type of combination of life history traits? | A Ruderal plant, thrives in increasing disturbance |
The Wooly lousewort is an example of what type of combination of life history traits? | A Stress tolerators, thrives in increasing stress |
The Goldenrod is an example of what type of combination of life history traits? | A Competitor, thrives in increasing competition |
Name the four life history traits. | 1. Potential Growth Rate 2. Age of Sexual Maturity 3. Proportion of Energy Used to Make Seeds 4. Importance of Vegetative Reproduction |
Name the life traits for stress tolerators. | Slow potential growth rate, Late age of sexual maturity, Low proportion of energy used to make seeds, Frequently important of vegetative reproduction |
Name the life traits of competitors | Fast potential growth rate, Early age of sexual maturity, Low proportion of energy used to make seeds, Often important |
Name the life traits of ruderals | Fast potential growth rate, Early age of sexual maturity, High proportion of energy used to make seeds, Rarely important |
Among 14 populations and species of goldenrod plants, individuals that produce more seeds also produce smaller seeds, demonstrating that _____ exists between the two life history traits. | A trade-off |
In the European magpie, the adults typically lay seven eggs. When researchers removed one or two eggs or added one or two eggs. the number of chicks that survived to fledge declined. What does this suggest? | This suggests that the typical number of eggs laid may be the optimal number for the magpie. |
When researchers removed eggs from kestrel nests, fewer chicks fledged but male/female parents experienced increased survival. When eggs were added, more chicks fledged but it came at the cost of the parents experiencing decreased survival. This suggests? | This suggests that parental care is directly correlated to parental survival. |
Using hundreds of different populations and species, we can see that different groups of animals have different relationships between what two life history traits? | Expected survival past sexual maturity and female age at sexual maturity |
Bamboos and agaves are two groups of plants that live for many years, reproduce one time, and then die. What type of reproductive strategy do these plants use? | Semelparous strategy |
Guppy populations in streams with a high risk of predation have shorter life spans and those in streams with low predation risk have longer life spans. In response to this difference in longevity, guppies living in predator environments have evolved to..? | Mature as smaller males, allocate a greater fraction of energy to offspring, produce more offspring, and produce smaller offspring. |
In the species Yucca whipplei, some varieties are semelparous and other varieties are iteroparous. Over its lifetime, the semelparous variety produces...? | More flowers, more fruits, and a higher percentage of seeds that germinate. |
The 13- and 17- year cicadas use what reproductive strategy? They spend many years underground, emerge as adults to breed, and die soon after. | Semelparous |
Throughout life, humans experience a gradual decrease in physiological function and an increase in cancer and cardiovascular diseases. These contribute to increased probability of mortality. This is called what? | Senescence |
In the barking treefrog, an individual living under high food is able to metamorphose at a large mass and young age vs. low food conditions could achieve the same age at a smaller mass. Why doesn't the frog wait till it's the same size? | It could achieve the same mass at metamorphosis if it took longer to metamorphose. In reality, they reach a compromise and metamorphose at a somewhat smaller mass and a somewhat later age. |
True or false. The amount of food available can affect an organism's mass and age at metamorphosis. | True. |
How can the effects of predation affect an organism's life history? | Example, As the cat-eyed snake begins to attack the eggs of the red-eyed treefrog, the embryos are stimulated to hatch early. |
How can the effects of global warming affect an organism's life history? | Example, Egg laying dates collected over a 42 yr period demonstrate that tree swallows bred 9 days earlier in 1991 than in 1959. The variation in egg laying date is negatively correlated with the mean air temperature in May. |
How can the effects of global warming affect plants life history? | Example, The mean flowering time today is 7 days earlier than in the 1850s. The variation in first flowering time is associated with the mean temperature of the 1 or 2 months preceding each species' flowering time. |
For several decades, commercial fishing vessels have harvested the largest individuals and thereby caused what? | Human selection on the life history of fish, unintentionally selecting for smaller fish. |
Life histories are shaped by trade-offs. Describe specific reasons for trade-offs. | Physical constraints, time or energetic constraints that affect allocation, or genetic correlations that cause selection favoring one trait to come at the cost of another trait. |
What are some common trade-offs? | Offspring number versus offspring size, and growth versus reproduction. |
True or false. Organisms differ in the number of times that they reproduce, but they all eventually become senescent. | True. |
What are some of the most common environmental influences on life history traits? | Variation in resources and predators which can both induce substantial changes in the life history of organisms. Anthropogenic changes can also affect life history traits by altering environmental cues-such as temperature-that induce life history changes. |