H1+Populations+and+population+structure

=**POPULATIONS AND POPULATION STRUCTURE:** =

**Population:**
• A population is a group of organisms of the same species the occupy any given area. • Populations can be put into two different categories: unitary or modular organisms. • Unitary: each zygote gives rise to a single individual. • Modular: each zygote develops into a unit of construction which gives rise to further modules and a branching structure.

**Population size:**
• Unitary: for mammals is the number of individuals in a given area. • Modular: plants and corals, population is the number of “pieces” or the number of shoots (modules) gives a better indication of abundance than the different individuals.

**Age and stage structure:**
• Age structure is the number of individuals in each age class expressed as a ratio, and is displayed as an age pyramid diagram. (see diagram below) • A population that neither expands nor contracts will have a stationary age distribution. • A growing population will have more young, while declining populations will be dominated by older age classes.


 * VOCABULARY:**


 * POPULATION:**


 * Unitary organisms:** Each individual is produced directly from a zygote and the form and development is highly predictable.


 * Modular organisms:** The zygote develops into a unit of construction, or module. This gives rise to other modules to form branching structures.


 * Ramets:** Connections between the parts of spreading modular organisms that are derived from a single zygote. (Essentially any apendages that branch off of an organism)




 * Clone:** A large congregating group of ramets.


 * POPULATION SIZE:**


 * Evolutionary individuals:** Make up the categorization of life. Genes, bacteria like cells, eukaryotic cells, multi-cellular organisms, and societies.


 * Immediate ecological impact:** A species impact on the natural environment.


 * AGE and STAGE STURCTURE:**


 * Stable age distribution:** Comes from where the ratio of one age group to the next stays the same shape of the age pyramid, with no change over time.


 * Stationary age distribution:** Part of a population that neither increases nor decreases. The structure is stable and the population size remains the same.


 * Stage structure:** The number of individuals present in discrete growth stages.


 * Indeterminant:** Not linked to age.


 * Size Classes:** Include mass, area covered, or diameter at breast height (DBH). All of these are more useful than age because some plants of the same age and species will have a greater size.