Ecology Day Two

Ecology

Gout-all the things that are wrong with people.

· As density goes up so does limiting factors. Disease is not a limiting factor yet. Flu shots- dead virus, how to predict that it’s the one we use. They don’t know for sure. It comes from China. The population is so dense they get the flu first. We make a flu shot for the Northern hemisphere. Their summer is our winter.

· Ecologists look at the limiting factor.

· Delta N/delta t =rN(K-N/K) logistic growth. S curves start as exponential, stable off then, if it dips then limiting factors have taken affect.

Types of growth- exponential, logistic,

Population cycles are fluctuations in populations size in response to varying effects of limiting factors. Since many limiting factors are density dependent they will have a greater affect when the population size is greater compared to when it is small.

Instead of limiting the cockroaches, whipping them all out then allowing them to thrive.

K-selected species- is one whose population size remains constant at the carrying capacity, K. Species of this type such as humans, produces a small number umber of relatively large offspring that require parental care until they nature. Reproduction occurs repeatedly during their lifetime.

S curve characters, K-selected species are not the ones to come in stabilize they come in second, they come in to an established community. They have small clutch sizes. They need time to mature and parental care. They hover at the carrying capacity. They stabilize the population. A lot older reproductive maturity, takes them years to reproduce. Old reproductive age, small clutch size, years in frequency reproduction, old reproductive lifetime, long survivorship of offspring to reproduce maturity.

R curve- Rapid reproductive maturity set the exponential curve. Large clutch size. They have young reproductive age, large clutch size, short in frequency reproduction, young reproductive lifetime, short survivorship of offspring to reproduce maturity.

Reduction in disease, Advances in medicine, such as the discoveries of antibiotics, vaccines, proper hygiene, reduced the death rate and increased the birth rate.

Reduction of wastes water purification and sewage systems, health hazards from human wastes were reduced. Increased waste collected more exponential population growth. Expansion of habitat- better housing warmer clothing, easy access to energy for heating, cooling, and cooking, for example, allowed humans to occupy environments that were previously unsuitable.

Community Ecology- is concerned with the interaction of populations. Interspecific competitions (between different species), the following concepts are how the competition is resolved: Intra- same species.

The competitive exclusion principle (Gause’s Principle), When two species compete for exactly the same resource or they occupy the same niche and they both need the smaller seed, one is more likely to be successful, One species outcompetes the other and eventually the second species is eliminated.

The other goes and finds another niche. If they are smart enough tto do that.

Resource partitioning: Some species cexist in spite of the apparent competiton for the same resources. They occupy different niches. By pursuing slightly differently resources or securing their resources in slightly diffecrnt ways, individuals, minimize competions and maximize success. Dividing up the resources in this manner is called resource partioning.

Harter displacement (niche shift) As a result of resource partitioning , certain characteristics may enable individuals to obtain resources in their partitions more successfully. Selection for these characteristics or characters reduces competition with individuals in other partitions and leads to a divergence of features, or character displacement.