Population studies by sampling methods
Population is the total number of organism of the same specie which live at a given time in a particular habitat. E.g human population in a state or country for ten years.
Ecology of population studies
* Population density: this is the number of individuals per unit area or volume at a particular time. Example: a number of human in habitat per square kilometer, number of trees per square hectare in a forest. Population density can be estimated by a. direct counting, b. tagging c. quadrant sampling.
PD= number of organism (population size)
Area
* Population size: factors responsible for population size are:
a. Natality: production of new individuals by birth, hatching or germination.
b. Mortality: it is the rate of removal of individuals from the population through death
c. Immigration: it is the movement of organism into a population
d. Emigration: it is the movement of organism out of the population.
e. Dispersion: it is the manner in which individuals in the population are spread in a particular area.
* Population dominance: those specie that have a major controlling influence on the nature of community they are. And these species are called dominant. These dominant could be inform as most numerous, using the most available space, making large contributions.
Factors affecting population growth
* Space and food: there is a particular number of specie that a particular amount of space can hold. This is called the carrying capacity of the environment.
* Predators: this help to regulate the population of prey.
* Parasitism and disease: helps to check the population growth.
* Climate:
* War
* Natural disaster
* Competition: this is an interaction between organisms of either same or different species for the same climate resources such as food, water, space, light, temperature, mates. E.t.c
Types of competition
a. Intraspecific competition: competition between same specie
b. Interspecific competition: competition between different specie
ECOLOGICAL FACTORS
Ecological or habitat factors are those factors that affect or influence an organism in a habitat and control its survival and distribution in the habitat. It is grouped into two: biotic factor: which is concerned with the effect of plants and animals on one another in a given habitat. E.g completion, parasitism, predation. Abiotic factor: this include the physical environment such as climate, edaphic, and topographic factors.
a. Ecological factors affecting terrestrial habitat
* Topographic factors: these factors are associated with the structure of the habitat e.g mountain, hills. E.t.c these factors include:
a. Altitude: it is the height of the land above the sea.
b. Slope.
* Edaphic factor: these are factors related to the soil. Which play an important role in determination the vegetation and animals in a habitat. They include:
a. Soil type
b. Soil texture
c. Soil PH
d. Soil structure
* Atmospheric factor (relative humidity): this is a measure of the amount of moisture(water vapor) in the air. And it is affected by temperature, rainfall and wind.
b. Ecological factors affecting aquatic habitat
* Salinity: this refers to the concentration of salts in the water.
* Turbidity: known as transparency, which refers to the cloudiness of water or amount of suspended particles in water. Clean water has low turbidity.
* Speed of flow/water currents: which is the flow of water in an aquatic habitat.
* Tides: movement of water caused by the gravitational pulls of the sun, moon and the earth on water.
* Waves: movement of water caused by wind blowing.
* Density: it is the mass per unit volume. And water is denser than air.
* Dissolved gases: this refers to the amount of dissolved gasses such as oxygen, carbon dioxide e.t.c which decrease with depth.
Ecological factors common to all habitat
* Rainfall
* Temperature
* Light
* Wind
* Pressure
* Hydrogen ion/PH
Biotic factors affecting the ecosystem
* Parasitism
* Competition
* Commensalism
* Predation
* Trampling
* Pollination
* Aeration of the soil
* Support provided to climbing
* Shade provided by trees.
Importance of ecological factors to the population of plants and animals.
* They support metabolic activities
* Provides conducive environment for survival
* Helps in population control