14.1: Habitat & Niche  Key concept: Every organism has a habitat and a niche.

What’s the difference between a habitat and niche?  Habitat: All of the biotic & abiotic factors in the area where an organism lives (i.e. grass, trees, watering hole)  Niche: Includes the same as the habitat. (All of the physical, chemical, and biological factors that a species needs to survive, stay healthy, and reproduce),but also includes the animals behaviors. (i.e. type of food species eats, temperature it can tolerate, time of day it is active, how it interacts with others)  Habitat is where a species lives (“address”), niche is how it lives there (“job”)

14.2: Community Interactions  Key concept: Organisms interact as individuals and as populations

Competition and predation are two important ways in which species interact. 1. Competition: Two organisms fight for the same limited resources.  Intraspecific: members of the same species (Ex: territory fights)  Interspecific: Two different species Ex: Plants (fighting for the same space) 2. Predation: One organism captures and feeds upon another organism.

Symbiosis is a close ecological relationship between two or more organisms of different species that live in direct contact with one another.  Mutualism: Both species benefit from one another. Example: bat & cactus  Commensalism: One species benefits from the other, the other is neither helped nor harmed. Example: Humans & demodicids  Parasitism: One organism benefits while the other is harmed. Ex.: Tapeworms  Endoparasite: Live in the tissues and organs of the host  Ectoparasite: Lives on the exterior of the host

14.4: Population Growth Patterns  Key concept: Populations grow in predictable patterns.

Population Size Changes  Increased Population 1.Immigration: Movement of individuals into a population from another population Ex: fruit flies and banana 2. Births: increases the number of individuals in a population. Ex; additional flies born  Decreased Population 3. Emigration: Movement of individuals out of a population and into another population Ex: some flies get out 4. Death: the size of the population decreases when individuals die. Ex; fruit flies get squashed.  The rate of growth for a population is directly determined by the amount of resources available.

Types of Population Growth  Exponential Growth – occurs when individuals reproduce at a constant rate under ideal conditions; population size increases dramatically over a period of time.  Examples: J-curve, human population

Types of Population Growth  Logi s tic Growth – population rises exponentially and then growth slows when it reaches its carrying capacity.  Carrying capacity: The maximum number of individuals of a particular species that the environment can normally and consistently support.  S-shaped Curve

What affects the carrying capacity of a population?  Factors that have the greatest effect at keeping down the size of a population are called limiting factors.  They can be density-dependent or density- independent.

Density-dependent limiting factors  Affected by the number of individuals in a given area  Examples: Competition, predation, parasitism, disease

Density-Independent Limiting Factors  Aspects of the environment that limit population growth regardless of population size.  Examples: Unusual weather, natural disasters, human activities.

14.5 Ecological Succession  Key concept: Ecological succession is a process of change in the species that make up a community.

Succession occurs following a disturbance in an ecosystem.  Succession : the sequence of biotic changes that regenerate a damaged community or create a community in a previously uninhabited area.

Primary Succession  The establishment and development of an ecosystem in an area that was previously uninhabited.  Can begin due to melting glaciers, volcanic eruptions, or landslides.  First organisms to live in a previously uninhabited area are called pioneer species.  Examples: lichens and mosses that can break rock down into smaller pieces.

Secondary Succession  The reestablishment of a damaged ecosystem in an area where the soil was left intact.  Plants and other organisms that remain start the process of regrowth.  Small disturbances start the process again and again.  Example: forest fire, tree falling