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Population ecology
This document defines key terms and concepts in population ecology, including population growth patterns, competition, predation, and symbiosis. It explains that a population's size is determined by birth and death rates, and that populations can grow exponentially or logistically. Interspecific and intraspecific competition occur when organisms compete for limited resources. In a predator-prey relationship, the populations influence each other's sizes. Symbiosis includes parasitism, mutualism, and commensalism interactions between species.
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Population ecology
- 1. POPULATION ECOLOGY. POPULATION SIZE ANDINTERACTION IN THE ENVIRONMENT
- 2. POPULATION ECOLOGY TERMINOLOGY POPULATIONIS THE STUDY OF THE FACTORS THAT CAUSE CHANGES IN THE NUMBER OF ORGANISMS IN A POPULATION. IMMIGRATION- IS A ONE WAY MOVEMENT INTO A POPULATION AREA. EMIGARTION- IS A ONE WAY OUTWARD MOVEMENT OF INDIVIDUAL FROM A STABLE POPULATION AREA. NATALITY(BIRTH RATE)- IS THE NATURAL (INHERENT) ABILITY OF A POPULATION TO INCREASE. MORTALITY (DEATH RATE)- IS THE RATE AT WHICH INDIVIDUALS OF A POPULATION DIE.
- 3. TWO MAIN PATTERNSOF POPULATION GROWTH. There are two main patterns of population growth: 1. Exponential growth/J-pattern: only one reproductive chance is given to members of the population during their entire lifespan. Once mission accomplishes, they die. e.g. insects and annual plants reproduce in this manner. 2. Logistic growth/S-pattern: members experience many reproductive events throughout their lifetime. e.g. Most vertebrates, and trees have this pattern of reproduction.
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- 5. Exponential growth/J-pattern Lagphase: Growth is slow because population base is small. Exponential growth phase: Growth is accelerating, the rate of growth itself grows.
- 6. Logistic growth pattern/S-shape
- 7. Logistic growth pattern/S-shape Lag phase: Growth is slow because the population base is small, organisms adapt. Exponential growth phase: Growth is accelerating, that is, many offspring born at a fast rate. Deceleration phase: The rate of population growth slows down – individuals start to die. Stable equilibrium phase: Little growth because births and deaths are about equal. Area has reached its carrying capacity. Carrying capacity (K) is the maximum population size the environment can support
- 8. COMPETITION. Species interactionthat “benefits” one species and neither helps nor harm the other. E.g. an epiphytic orchid and the plant on which it grows, whereby having an elevated perch benefits the orchid, and the tree in unaffected.
- 9. Limited supplyof at least one resource (such as food, water, and territory) used by both can be a factor.
- 10. Interspecific competition inecology, is a form of competition in which individuals of different species compete for the same resource in an ecosystem (e.g. food or living space)
- 11. Intraspecific competition isan interaction in population ecology, whereby members of the same species compete for limited resources. This leads to a reduction in fitness for both individuals.
- 12. predation Is arelationship in which members of one species ( the predator)consume of another species (the prey). For instance, lions (predator) consume zebras (prey).
- 13. Predator-prey relationship Apredator-prey relationship tends to keep the population of both species in balance. As the prey population increases, there is more food for predators. Then the prey population slightly lag, while the predator population increases as well. Then more prey are captured, in a while the population will be existent. This will leave the predator population with no food, and affect the number of the population.
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- 15. (INTERACTION) SYMBIOSIS. Symbiosismeans “living together” is a relationship where two or more species live in direct and intimate contact with one another. There are three types of symbiotic relationship viz. 1.Parasitism 2.Mutualism 3.commensialism
- 16. 1.parasitism In thisrelationship one organism which is called “parasite” get food or “benefit” from another organism, which is called a “host” is harmed in the process There are two types of parasites. 1. endoparasites- they live inside the body. 2. Ectoparasites- they live on the external surface. e.g. a “tick” suck blood from a “cow”
- 17. 2.Mutualism The interspecificinteraction that “benefit” both participants. E.g. a flowering plant and a pollinator.
- 18. 3.commensalism Species interactionthat “benefits” one species and neither helps nor harm the other. E.g. an epiphytic orchid and the plant on which it grows, whereby having an elevated perch benefits the orchid, and the tree in unaffected.