Science - I. Characteristics of Populations
What is the range of the population?
It's geographic distribution - the area that is inhabited by the population.
What determines which type of reproduction an organism will have?
It's survival rate.
If the adults are more likely to survive and reproduce again, what type of reproduction is it?
repeated reproduction
What is dispersion?
spatial distribution of individuals within a population.
A population's size is?
the number of individuals in the population.
What is Repeated Reproduction?
the organism produces a few offspring each year for several years.
How is the future growth of a population is predicted?
using the distribution of individuals among different ages in a population
What are the two main type of organisms reproduction?
1. Big-bang reproduction 2. Repeated reproduction
What are the 3 main changes to consider that take place in a population?
1. Birth rate: the number of births occuring in the given period of time 2. Death rate or mortality rate: the number of deaths in a given period of time 3. Life expectancy: the length of time an individual is expected to live
Explain why it would be difficult to count the population of bullfrogs in Everglades National Park?
1. Park size very large - Park size is 1.5 million acres or 6,110 km2.) 2. To determine the size of this population, scientists would have to use various methods of estimation, sampling, etc. which have the potential for error.
What are the (6) important characteristics of a population?
1. Population size 2. Geographic Distribution 3. Density 4. Dispersion 5. Growth Rate 6. Age structure
Density is one of the main characteristics that describes what?
1. a population.
Define population?
A group of individuals belonging to the same species that live in the same area at the same time.
Why is a population of daises in a field easy to measure but a population of individudals is hard too count? i
Daisies - Easy to count 1. The plants are immobile 2. confined to a relatively small area. 3. scientist would simply count the individual plants in the field. Individuals - Hard to count - too: 1. widespread, 2. abundant, 3. mobile - can't be easily counted.
Give an example of big-bang reproduction.
Pacific salmon spend several years growing and maturing. Near the end of their life they spawn, producing millions and millions of eggs, followed by death.
What are the trade-offs in reproduction and survival?
Reproduction requires: 1) time, 2) energy, 3) resources. If all the resources are used up during reproduction, the survival is in jeopardy. If all the resources are needed for survival, then reproduction cannot occur.
What is a very important property of a population that can be difficult to measure?
Size
The mortality rate of the individuals in the population generally follows one the following patterns:
Type 1, 2 or 3 Survivorship Curves
Give an example of predicting through future growth of a population
a population with a large number of very young individuals is predicted to have a higher growth rate in the future when these individuals reach reproductive age.
What is a Type 2 (II) Survivorship Curve?
a) This curve is: intermediate to above 2 curves b) here is a constant death rate over the organism's life span. c) The probability of dying does not change throughout life. d) This may occur in rodents and lizards.
All populations are dynamic, meaning that they ?
a) change in size and composition over time
What is a Type 1 (I) Survivorship Curve?
a) curve is flat at the beginning, indicating a low death rate in the early and middle stages of life b) It drops steeply near the end indicating: A high death rate as the organisms become older. c) An example is large mammals that produce very few offspring, but provide them with good care.
What is a Type 3 (III) Survivorship Curve?
a) drops sharply at the start, indicating a high death rate among the young b)flattens out as death rates decline for the few that do survive the early die-off c) includes organisms that produce large numbers of offspring, but provide them with little or no care.
What is clumped dispersion?
a) individuals are clustered together b) occurs when: Resources such as food, water, or living spaces are clumped together. c) may also occur because a species has: A certain social behavior such as herding animals, flocks of birds, schools of fish or hives of bees
What is uniform (even) dispersion?
a) individuals are separated by a fairly even distance. b) result of social interactions, but the interaction results in the individuals trying to get as far away from each other as possible.
What is random dispersion?
a) location of one individual is independent of the location of the other individuals. b) may result from seed dispersal by the wind or animals. c) forest or a field of wildflowers results from the random dispersal of seeds.
The life history of an organism is the __________ that affect an organism's schedule of ___________________ and ____________________.
a) traits b) reproduction c) survival.
There is tremendous variation in _________________ depending on the _______________ and the ________________. Some populations have __________ densities, while other populations have _____________densities.
a. density b. Species and ecosystem c. low d. high
What is age structure?
a. the distribution of individuals among different ages in a population b. Age structure is often presented in graphs
What is big-bang reproduction?
an organism produces all of its offspring in a single event.
If the survival rate of the offspring is low, it is more likely to have what type of reproduction?
big-bang
What are the 3 types of dispersion?
clumped, uniform (even), random