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Questions and Answers
What does a life table record?
What does a life table record?
What is the main purpose of a life table?
What is the main purpose of a life table?
How is the rate of mortality calculated using a life table?
How is the rate of mortality calculated using a life table?
What does 'QX' represent in the context of a life table?
What does 'QX' represent in the context of a life table?
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How can life tables be used in predicting population dynamics?
How can life tables be used in predicting population dynamics?
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What information does a life table provide about a population?
What information does a life table provide about a population?
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In a life table, what does 'dx' represent?
In a life table, what does 'dx' represent?
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What type of study provided more powerful means for analysis of organisms?
What type of study provided more powerful means for analysis of organisms?
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During which centuries were organisms collected, cataloged, and studied in different environments?
During which centuries were organisms collected, cataloged, and studied in different environments?
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Who published the theory of evolution in the 18th and 19th centuries?
Who published the theory of evolution in the 18th and 19th centuries?
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What marked the emergence of ecosystems in the 20th century?
What marked the emergence of ecosystems in the 20th century?
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What kind of worldview shifted from mechanistic to holistic/ecological?
What kind of worldview shifted from mechanistic to holistic/ecological?
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Which scientific approaches emphasized parts and reductionism?
Which scientific approaches emphasized parts and reductionism?
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Which framework focuses on controlling conditions for maximizing gains?
Which framework focuses on controlling conditions for maximizing gains?
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What has led to significant increases in available energy beyond biological sources?
What has led to significant increases in available energy beyond biological sources?
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Which approach is efficient in bringing desired outcomes but can lead to unforeseen consequences?
Which approach is efficient in bringing desired outcomes but can lead to unforeseen consequences?
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Study Notes
Population Dynamics
- A population is a group of individuals of the same species, occupying a particular space at the same time, sharing the same gene pool.
- Population dynamics is the study of the dynamics of species populations and how they interact with the environment.
Survivorship Curve
- A graphical presentation of survivors of a life table.
- Obtained by plotting the population of survivors of a particular age cohort.
- Types of survivorship curves:
- Rapid growth (wide base and thin top): More people die at each higher age level. Higher birth rate and death rate. (Developing country)
- Slow growth (stable populations): High life expectancy. (US)
- Zero growth (unchanging rate of birth and death): No growth or decline. (Canada)
- Negative growth (graying population): Higher proportion of older individuals and fewer young individuals. (Germany, Japan)
Age Structure and Sex Ratio Pyramid
- A graphical representation of a population at a specific moment in time.
- Clustered according to age and sex categories.
- Density = (B - D) + (I - E), where B is natality, D is mortality, I is immigration, and E is emigration.
Population Growth
- Modeling population dynamics helps quantify change and predict future changes.
- Relies on the biotic potential of individuals in the population.
- Population growth can be affected by demographic factors such as birth, death, immigration, and emigration.
Sex Change
- Sequential hermaphroditism: Organisms undergo sex reversal. (e.g., fish, oysters)
- Protandrous: Born male, eventually become female.
- Protogynous: Born female, eventually become male.
- Cause of sex change: Reach 80% of maximum body size and social factors (removal of males).
Sexual Reproduction
- An innate characteristic of animals to pass on genes and promote variability and avoid extinction.
- Dioecious: Male and female found in separate organisms.
- Social insects: Efficient in gathering food, assume roles, and follow rules. Eusociality: Reproductive division of labor among members.
Demography
- The study of vital statistics of population and how they change over time.
- Demographic factors influence population size: birth, death, immigration, and emigration.
Logistic Equation
- dN/dt = rN(1 - N/K), where N is population size, r is intrinsic rate of increase, and K is carrying capacity.
- Describes the growth of a population over time, considering the carrying capacity of the environment.
Applications of Population Ecology
- Conservation of diverse plants and animals.
- Control of noxious pests, including viruses, parasites, and pathogens.
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Description
Explore survivorship curves and different population growth patterns such as rapid growth, slow growth, zero growth, and negative growth. Understand the characteristics of each curve and their implications on population structure.