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Population Ecology Concepts
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Population Ecology Concepts
Population Ecology Concepts
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1
Question
What is the definition of a population?
Answer
A population is the total number of individuals of the same species that occupy a specific area and that are able to interbreed with one another at a specific time.
2
Question
Give examples of a population.
Answer
1. A particular species of fish living in a pond. 2. All the silkworms in a shoebox at a particular time. 3. Individuals of a particular species in Kruger Park, such as several packs of wild dogs.
3
Question
What is population ecology?
Answer
Population ecology is the study of populations.
4
Question
What are the characteristics of a population?
Answer
1. Density: The number of individuals per unit area or per unit volume. 2. Sex Ratios: The ratio of male and female individuals within the population. 3. Pattern of Distribution: Refers to how individuals are distributed over the area they occupy.
5
Question
What are the types of distribution patterns in a population?
Answer
1. Random Distribution: No particular pattern. 2. Clumped Distribution: Grouped together in specific places. 3. Uniform Distribution: More or less the same distance from one another.
6
Question
What is a species?
Answer
A species is a group of closely related organisms that can interbreed and produce fertile offspring.
7
Question
What are population parameters?
Answer
Population parameters are factors that determine the size of a population and the changes that occur to its size over time.
8
Question
What parameters affect population size?
Answer
1. Birth Rate (Natality): The rate at which new individuals are added to a population through reproduction. 2. Death Rate (Mortality): The rate at which new individuals are lost to a population through death. 3. Immigration: The rate at which new individuals join a population from somewhere else. 4. Emigration: The rate at which individuals leave a population to go somewhere else.
9
Question
What is a habitat?
Answer
A habitat is the place where a plant or animal lives.
10
Question
What is a random sample?
Answer
A random sample is a sample that is not deliberately selected but is selected by chance and therefore has an equal probability of being chosen.
11
Question
What is the easiest method for measuring the size of a population?
Answer
Counting, also referred to as a direct count, is the easiest method for measuring the size of a population.
12
Question
What is a quadrat?
Answer
A quadrat is a square frame with a known area used to investigate the types of species, the number of individuals, and their distribution in a habitat.
13
Question
What is a transect?
Answer
A transect is a line formed by a tape or rope stretched across part of an ecosystem, used to identify and record the position of each plant or animal found on the line.
14
Question
What are pitfall traps?
Answer
Pitfall traps are jars or cups with smooth inner surfaces buried in the ground at surface level, where small animals fall in and cannot escape.
15
Question
What is the mark-and-recapture method?
Answer
The mark-and-recapture method is used to measure the size of an animal population by capturing animals, marking them, releasing them, and later recapturing to count how many marked individuals are found.
16
Question
What precautions should be taken for the mark-and-recapture method?
Answer
1. Choose a stable population. 2. Take random samples from different areas. 3. Ensure that the marks do not harm the organisms. 4. Marks must last until the second sample is taken. 5. Allow enough time for the animals to mix after release.
17
Question
What are limiting factors in population growth?
Answer
Limiting factors affect population growth and can be density-dependent or density-independent.
18
Question
Give examples of density-dependent limiting factors.
Answer
Density-dependent limiting factors include competition, predation, and diseases, which have a greater effect as population size increases.
19
Question
Give examples of density-independent limiting factors.
Answer
Density-independent limiting factors include earthquakes, floods, and fires, which affect populations in the same way, regardless of population size.
20
Question
What is carrying capacity?
Answer
Carrying capacity refers to the maximum number of individuals that an ecosystem can support, linked to the availability of resources such as food, space, and shelter.
21
Question
What is environmental resistance?
Answer
Environmental resistance refers to the combined effect of limiting factors such as food, space, mates, predation, and diseases.
22
Question
What is logistic growth?
Answer
Logistic growth is an S-shaped population growth curve that starts with exponential growth under ideal conditions, followed by a slowing down as resources become limited.
23
Question
What is natality?
Answer
Natality is the birth rate, the rate at which new individuals are added to a population.
24
Question
What is mortality?
Answer
Mortality is the death rate, the rate at which new individuals are lost to a population through death.
25
Question
What is exponential growth?
Answer
Exponential growth is when a population increases in size rapidly under ideal conditions, represented by a J-shaped curve.
26
Question
What is a lag phase in population growth?
Answer
The lag phase is a period of slow growth as the population gets used to the environment.
27
Question
What is the decelerating growth phase?
Answer
The decelerating growth phase is when the rate of growth slows down due to increasing environmental resistance.
28
Question
What are the causes of slow population growth?
Answer
Increased competition for resources, increased predation, and diseases cause slow population growth.
29
Question
What is a negative feedback mechanism in population dynamics?
Answer
A negative feedback mechanism is a mechanism in which two populations regulate each other, such as the predator population regulating the prey population and vice versa.
30
Question
What is geometric growth?
Answer
Geometric growth refers to populations that grow exponentially, doubling at regular intervals, such as bacteria that reproduce by binary fission.