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: All of the physical, chemical, and biological factors that a species needs to survive, stay healthy, and reproduce (i.e. type of food species eats, temperature it can tolerate, time of day it is active)  Habitat is where a species lives (“address”), niche is how it lives there (“job”)

Living things need food, water, and shelter to be successful  Competitive exclusion principle: when two species are competing for the same resources, one species will be better suited to the niche, pushing the other species to another niche or extinction.  Other outcomes  Evolutionary response  Example: selection for different tooth size in different squirrel species, allowing each to eat different food in the same area.  Niche partitioning (next slide)

 Ecological equivalents are species that occupy similar niches but live in different geographical regions.

STOP & REVIEW  What is the difference between a habitat & a niche?  A habitat is where a species lives, a niche is how it lives there/what it needs to survive  What are the possible outcomes when two species are competing for the same resources?  One species moves to another niche, one species becomes extinct, an evolutionary response, or niche partitioning.

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

Competition and predation are two important ways in which species interact.  Competition: Two organisms fight for the same limited resources.  Intraspecific: members of the same species  Interspecific: Two different species  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 

STOP & REVIEW  What is the name for a close ecological relationship between two or more organisms of different species that live in direct contact with one another?  Symbiosis  What type of relationship exists between two organisms when one is benefiting from the relationship and the other is neither helped nor harmed?  Commensalism

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

Population Size Changes  Increased Population  Immigration: Movement of individuals into a population from another population  Births  Decreased Population  Emigration: Movement of individuals out of a population and into another population  Deaths  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

STOP & REVIEW  In a logistic growth model, the population grows exponentially until it reaches the ______________, then the growth will level off.  Carrying capacity  The carrying capacity refers to the maximum number of individuals of a particular species that the environment can:  Normally and consistently support.

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 (population density)  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.

STOP & REVIEW  This aspect of the environment will limit population size regardless of the initial population size.  Density-Independent Limiting Factors  Examples of density-dependent limiting factors include:  Competition, predation, parasitism, disease.

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.  s s

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

STOP & REVIEW  This type of succession can happen again and again in the same ecosystem.  Secondary