Ecology The Living World Pages 32-33, 686-735.
Succession • The series of stages that plants go through from pioneer community to climax community. • Primary vs. Secondary • Pioneer • Seral • Climax
Reasons for Succession • Tolerance – plants that are able to survive in barren areas with harsh abiotic conditions. Not good competitors. • Facilitation – early succession stages modify the environment to allow more favorable conditions for growth. • Inhibition – environmental changes by one species may negatively impact other species thus causing them to perish.
Niches • A pattern of life. • The sum total of all the ways and organism uses the resources of the environment – the biological role
Competition • Food, water, shelter, and mates. • Interspecific – • Intraspecific – • Competitive exclusion – If two species are competing for a resource, the species that uses the resource more efficiently will eventually eliminate the other species.
Resource Partitioning • Persistent competition between species is rare, instead species subdivide the niche or resource and use different parts. • Sympatric species – occupy the same area but use different parts of the ecosystem to avoid competition. • Allopatric species – no shared niche due to geographic separation; use the same food and resources because there is no competition.
Allopatric Species – No Competition http://www.zo.utexas.edu/faculty/sjasper/images/24.7.jpg
Symbiosis • Mutualism – both benefit • Commensalism – one benefits, one not impacted • Parasitism – one benefits, one negatively impacted, endo and exo parasites
Plant Defenses • Chemical • Structural • Behavioral
Animal Defenses • Defensive Coloration • Chemical Defenses • Behavioral • Structural
Predator Prey Relationships • Predator • Prey
Mimicry • Mimicry – When an organism has evolved to look like another organism for protection. • Mullerian Mimicry – Animals that resemble each other and are all protected. Ex. Yellow and black of stinging insects.
Mimicry Batesian Mimicry – one unprotected species has evolved to look like another species that is protected
Population • What is the world population? • How do populations increase or decrease? • What problems are associated with too much growth?
Factors that Increase Population • Natality – birthing, hatching, germination, cloning • Fecundity – physical ability to reproduce • Fertility – actual number of offspring an organism has • Immigration • Survivorship/Life Span/Life expectancy
Factors that Decrease Population Growth • Mortality • Emigration • War • Disease
Regulatory Factors • Density Independent Factors – Impact birth rate or death rate regardless of the number of individuals in the population. • Ex. Lightning Strike or Tornado
Factors that Regulate Population Size • Density Dependent Factors –Reduce birth or death rate because of the size (number of individuals) in a population. • Ex. Competition, predator-prey cycles, stress and crowding.
R- Selected Rapid growth Early reproduction High numbers of young Early maturity Little parental care Shorter life span Ex. Mice, roaches, lice K-Selected Limited resources Slower Growth Intense Parental Care Fewer young Later maturation Longer life span Ex. Humans, cats, cows Life History Adaptations
Conclusion Biomes Biogeochemical cycles Food Webs Energy Pyramids Succession Population Relationships Plant and Animal Defenses Mimicry All lecture notes, readings and labs