Post on 06-Jan-2018
description
LO’s
- the meaning of ecology, population symbiotic relationships- can explain population demographics and ways in which population sizes are regulated.- can explain various types of symbiotic relationships.
Ecology Population
Ecology• Study of the interactions between organisms and the
environment• Study of the physical and biological variables
governing the distribution & growth of living things
Population • Individuals of a given species occurring at one
place at one time• Population ecology– Study of population growth & interactions
Population
Is a groups of individual of the same species that live in the same area
1. Population Density:
2. Spatial Distribution:• Dispersion: The pattern of spacing a population within
an area (Way that individuals are arranged• 3 main types of dispersion• Clumped• Uniform• Random
Population Characteristics
• Number of organisms per unit area• Density influences survival
• Individuals evenly spaced• Often results from territoriality• Also plants with allelopathy
• Lacking definite order• Individuals do not influence
others growth
• Individuals form clusters• Clumping due to interaction of
individuals
Population Limiting Factors
3. Population growth rate– How fast a given population
grows– Factors that influence this
are:• Natality • Mortality• Emigration - movement
out of a population• Immigration - movement
into a population
Population Size
• (births + immigrants) – (deaths + emmigrants) = Population change
• Immigration – movement into a population
• Emigration – movement out of a population
Carrying Capacity• Indefinite exponential growth is limited• Shortages of growth factors will limit population
growth• Carrying capacity = maximum number that can be
supported in a particular environment
Population size
(births + immigrants) – (deaths + emigrants) = Population change
Boom & Bust Cycle
• Sometimes populations do not level off• Exponential growth with a sudden die-off
Interactions Within Communities
Community• Grouping of populations living together in a
particular area at a particular time
Abiotic Factors• Nonliving factors
within the environment– Air– Water– Rocks
• Abiotic factors affect living (biotic) factors
Biotic components are the living things that shape an ecosystem.
Biotic factor - any living component that affects another organism - needs energy to do work and food for proper growth - Plants, animals, fungi, protiste and bacteria
Ecosystem• Biotic & abiotic factors in a certain area• Biotic and abiotic factors combine to create a system
(ecosystem)
Habitat
• Space within an area where an organism lives
• Each organism plays a certain role
Niche• Two ways of defining– An organism’s role in the environment– Organism’s use of biotic & abiotic resources
Density Dependent Factors
• Factors that affect a population only if its density changes• Types of density dependent factors– Competition – Predation – Parasitism
Competition
• Interaction among organisms for the same resources– Food– Living space
• Regulates population size & is a driving force of evolutionary change
Competition Types• Intraspecific – among the same species• Interspecific – between species
Predation
• One species will kill & eat another
• Interactions maintain natural populations
• More prey results in more predators
• Less prey reduces predator numbers
Parasitism• One species living at the expense of another• Regulates populations by weakening or killing
Symbiosis is a close relationship between two or more different species.
There are 3 types of symbiosis we will discover:
Commensalism—A relationship where one species obtains food or shelter from the other species. Does not harm or help the other species.
Mutualism—A relationship where both species benefit from the relationship
Parasitism-- A relationship between two species in which one species (the parasite) nourishes itself to the disadvantage of the other species (the host).
Demography• Statistical study of human population • Human population is in exponential growth
Human Population Growth has Different Patterns
• Stable population– Remains the same– Same number entering reproductive age as at
end of reproductive age
• Population pyramid– Graphic representation of population age– Shows patterns in population change
Biotic and abiotic factors are interrelated. If one factor is changed or removed, it impacts the availability of other resources within the system