Population Dynamics Unit 1: Ecology What would be some potential problems if a population became too big?

Population Dynamics Population: All the individuals of a species that live together in an area Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

Size Density Population Dynamics Three Key Features of Populations Dispersion Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

Three Key Features of Populations Size: number of individuals in an area Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

Three Key Features of Populations Growth Rate: Birth Rate (natality) - Death Rate (mortality) How many individuals are born vs. how many die Birth rate (b) − death rate (d) = rate of natural increase (r) Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

Three Key Features of Populations Density: measurement of population per unit area or unit volume Pop. Density = # of individuals ÷ unit of space Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

How Do You Affect Density? Density-dependent factors: Biotic factors in the environment that have an increasing effect as population size increases (disease, competition, parasites) Density-independent factors: Abiotic factors in the environment that affect populations regardless of their density (temperature, weather)

How Do Populations Grow? Idealized models describe two kinds of population growth: Exponential Growth 2. Logistic Growth

How is Population Growth Predicted? Exponential Growth (aka “J-shaped” curve) occurs when population growth starts slow then increases rapidly. Logistic Growth (aka “S-shaped” curve) occurs when population growth reaches its carrying capacity due to limiting factors and levels off.

Carrying Capacity Carrying Capacity (k): The maximum population size that can be supported by the available resources There can only be as many organisms as the environmental resources can support Although several species may share a habitat they each have their own niche. A niche is a very narrow range where a species fits within a habitat.

How does an ecosystem work? An ecosystem changes over time. Species replacement is characterized by an ecological succession in which one community slowly replaces another as the environment changes. There are two types of succession: Primary which is the colonization of new land which was never inhabited Secondary, colonization of land that takes place after a natural disasters (hurricanes, earthquakes, etc) or human actions.

Reintroduction of Organisms The first organisms to inhabit an area are called pioneer species (lichen). The 2nd group of organisms to inhabit the area are bacteria, protists, mosses, and fungi The 3rd group include insects & arthropods The 4th group include grasses, herbs, shrubs, & trees http://www.youtube.com/watch?v=E0qdWoLdk1c

Checkpoint #1 Q: What are the 2 types of succession? A :Primary and secondary Q: The first group of species to inhabit an area are _________ example_____. A: Pioneer species example lichen Q: What are the last group of species to inhabit an area? A: trees and grass

Checkpoint #2 An active volcano under the ocean erupts, and the build-up of cooled lava eventually forms a new island. What type of succession will immediately occur on the newly formed island? A. primary succession C. both primary & secondary B. secondary succession D. no succession 2. A lack of food prevents further growth in a deer population. This is an example of a A. range of tolerance C. phonic zone B. limiting factor D. biome 3. When populations increase, resource depletion may result in A. exponential growth C. competition B. straight-line growth D. increase in predators

4. Type of population growth that reaches carrying capacity is called________. A. demography C. logistic B. exponential D. j- shaped 5. An example of a density dependent factor is __________. A. disease C. weather B. natural disaster D. seasonal cycles 6. An example of a pioneer specie would be_______.  A. pine trees C. maple trees B. lichen D. shrub Continued…