APES-Chap. 5-2 of 2-

What are the 2 aspects to stability in living systems?

- inertia, persistence -resilience

Logistic growth graph

- involves rapid exponential population growth followed by a steady decrease in population growth until the population size levels off- slowdown occurs as population encounters environmental resistance from declining resources and other environmental factors-approaches carrying capacity. After leveling off- fluctuates slightly above and below carrying capacity. ** Graph yields a sigmoid, or S-Shaped

In most large population, genetic diversity is fairly constant and the loss or addition of some individuals has little effect on the total gene pool. However, name the genetic factors that can play play a role in the loss of genetic diversity and the survival of SMALL isolated populations

1. founder effect 2. demographic bottleneck 3. genetic drift 4. inbreeding (remember these phenomena affect SMALL populations!!!

What is a limiting factor? Name the types of limiting factors.

Factors that limit the size of populations. Light Water Space Nutrients Exposure to too many competitors, predators or infectious diseases

What are Density-Independent population controls?

Factors- mostly abiotic- that can kill members of a population but are not dependent on the density of the population. Weather Hurricanes Flood Pollution Fire Habitat destruction

What might happen to a population if they exceed K?

May lead to a population crash and die off- example: reindeer on small Bering island

resilience

the ability of a living system to be restored through secondary succession after a moderate disturbance.

inertia (persistence)

the ability of a living system, such as a grassland or a forest, to survive moderate disturbances.

Define Natural ecological restoration and name two types of succession.

the gradual change in species composition in a given area over time. - Primary and Secondary succession

carrying capacity (K)

the maximum population of a given species that a particular habitat can sustain indefinitely without being degraded. (Together, biotic potential and environmental resistance determine the carrying capacity (K))

Population density

the number of individuals in a population found in a particular area.

Explain cyclic population changes and give examples(s)

- Boom and bust cycles in population -Top down population regulation(through predation) vs. bottom-up population regulation (Size of predator and prey population controlled by scarcity of one or more resources) - lemmings, whose populations rise and fall every 3-4 years

exponential or geometric growth graph

- a population with few, if any limitations on its resource supplies can grow exponentially at a fixed rate -starts slowly but then accelerates as the population increases, because the base size of the population increasing * J Shaped growth curve

Environmental Resistance

combination of all factors that act to limit the growth of a population

3 factors that affect the rate of succession

facilitation inhibition tolerance

genetic drift

random change in gene pool leads to unequal reproductive success, will change the frequencies of genes in the gene pool.

Primary and secondary succession can be interrupted by

Fires Hurricanes Clear-cutting of forests Plowing of grasslands Invasion by nonnative species

Type I survivorship curve characteristics

Type I survivorship curves depict a species with high survival rate through most of its lifetime, and a high mortality rate at the end. Animals (typically vertebrates) that have few offspring and invest heavily in their young fall in this category. Humans who have access to medical care and preventative medicine also follow these patterns of survivorship.

Type II survivorship curve characteristics

Type II organisms have a steady rate of mortality throughout their life span. Small animals such as squirrels, hydra, and migrating songbirds often follow this trend.

Type III survivorship curve characteristics

Type III organisms suffer tremendously high rates of mortality at an early age. Once individuals get through the bottleneck, however, they can live for a long time. Barnacles, for example, produce millions of young and release them into the sea. Most of the young drift along ocean currents and are eaten by predators. A few manage to settle in the rocky intertidal zone where they can find food and shelter. Those few individuals that make it there have an excellent chance of survival. Trees, insects, weeds and many aquatic species like clams would also be examples of type lll organisms. They make hundreds, even thousands of offspring but invest little energy in each. As a result many offspring do not find a favorable environment and die at an early age.

Explain irruptive population changes and give examples(s)

When a species' population growth occasionally explodes (irrupt) to a high peak and then crash to a more stable lower level or in some cases to a very low level. -many short-lived, rapidly reproducing species such as algae and many insects have irruptive population cycles linked to season changes in weather or nutrient availability.

Explain irregular population changes and give examples(s)

When a species' population has no recurring pattern regarding changes in population size. -Some scientist attribute to chaos in such systems/ other scientist contend may represent fluctuations in response to periodic catastrophic population crashes due to severe weather.

Describe stable population changes and give example(s)

When a species' population size fluctuates slightly above and below its carrying capacity. -characteristic of many species found in undisturbed tropical rain forests, where average temperature and rainfall vary little from year to year.

founder effect

when a few individuals in a population colonize new habitat that is geographically isolated from other members. Now face lower genetic diversity and may endanger population's stability

inbreeding

when individuals in a small population mate with each other, usually a demographic bottleneck has occurred.

What Population change pattern do predator/prey populations generally exhibit?

??- Cyclic (only thinking because of top-down and bottom up differentiation within definition)

What are density-dependent population controls?

Factors that limit population growth that have a greater effect as a population's density increases. Predation Parasitism Infectious disease Competition for resources

biotic potential

Species vary in their biotic potential or capacity for population growth under ideal conditions.

Species use different reproductive patterns to ensure their survival. Explain and give example of r-selected species.

Species with a capacity for a high rate of population increase (r). -have many, usually small, offspring and give them little or no parental care or protection. Examples: algae, bacteria, rodents, frogs, turtles, annual plants (dandelions) and most insects

Secondary succession

The other more common type of ecological succession is called secondary succession, in which a series of communities or ecosystems with different species develop in places containing soil or bottom sediment.

Survivorship curve

The way to represent the age structure of a population

Why do r-selected species tend to be opportunists?

They reproduce and disperse rapidly when conditions are favorable or when disturbance opens up and a new habitat or niche for invasion. - unfavorable changes in environment conditions or invasion by more competitive species may cause crash explaining why go through irregular and unstable boom and bust cycles in population sizes.

Species have different reproductive patterns that can help enhance their survival. What are K-selected or competitor species?

They tend to reproduce later in life and have a small number of offspring with fairly long life spans. -few big and strong individuals that can compete for resources -name related to tendency to do well in competitive conditions when their population size is near the carrying capacity (K) of their environment. -Examples: large mammals (elephants,, whales and humans), birds of prey, and large and long-lived plants (cactus and rain forest trees), orange roughy and sword fish

Conservation biologists use what concepts to estimate the minimum population size of rare and endangered species (ie. The number of individuals a population needs for long-term survival)

concepts of founder effects, demographic bottlenefk, genetic drift, inbreeding and island biogeography

inhibition

early species hinder establishment and growth of other species. Plants release toxic chemicals that reduce competition from other plants. Pine needles fall and make soil very acidic, so other species can't grow until fire comes along and removes the inhibiting species.

demographic bottle neck

hen a catastrophe (fire, hurricane) occurs and only a few individuals survive. These may not be the most fit individuals. The new population will have lower genetic diversity, and an increase in the frequency of harmful diseases.

Tipping point

here are limits to the stresses that ecosystems and global systems such as climate can take. As a result, such systems can reach a tipping point, where any additional stress can cause the system to change in an abrupt and usually irreversible way that often involves collapse.

Primary and secondary succession tend to increase biodiversity by

increasing species richness and interactions among species

Primary succession

involves the gradual establishment of biotic communities in lifeless areas where there is no soil in a terrestrial ecosystem or no bottom sediment in an aquatic ecosystem.

tolerance

late successional species are unaffected by plants at earlier stages of succession because they aren't in direct competition with them for resources. (Ie. They may be shade tolerant)

You will be given organisms present and need to predict the stage of succession

look over pages 115-117

facilitation

one set of species makes an area suitable for species with a different niche requirement, but less suitable for itself (lichens and mosses)