chapter 4/5 test

adaptive trait

any heritable trait that improves the ability of an individual organism to survive and to reproduce at a higher rate than other individuals in a population can under prevailing environmental conditions. For natural selection to occur, individuals with adaptive traits must have differential reproduction, which enables individuals with the trait to leave more offspring than other members of the population leave.

competition

between species for food, sunlight, water, soil, space, nest sites, etc. is interspecific competition. With intense competition for limited resources, one species must migrate, shift its feeding habits/behavior, or face extinction. As humans take more and more space, other species are compromised

generalist species

broad ecological roles

Stability

capacity of an ecosystem to withstand external stress and disturbance, is maintained by constant change in response to changing environmental conditions.

Five types of species interactions

competition, predation, parasitism, mutualism, and commensalism—affect the resource use and population sizes of the species in an ecosystem

Secondary ecological succession

defines a series of communities with different species developing in places with soil or bottom sediment.

Inertia

or persistence, is the ability of a system to survive moderate disturbances.

population size governed by:

population change (births + immigration) - (deaths + emigration) Age structure: - Pre-reproductive age - Reproductive age - Post-reproductive age

Four general types of population fluctuations

stable, irruptive, cyclic, and irregular Humans are not exempt from population crashes. Examples include the Irish potato famine, the bubonic plague, and the current AIDS epidemic

limiting factor principle

states that too much or too little of a physical or chemical factor can limit population growth even if all other factors are optimal

Prey can avoid predation by . . .

Camouflage Chemical warfare Warning coloration Mimicry Behavioral strategies

interspecific competition

Compete to use the same limited resources

indicator species

Indicator species provide early warning of ecosystem damage because they have a narrow range of tolerance

Carrying capacity

Maximum population of a given species that a particular habitat can sustain indefinitely can fluctuate seasonally or from year to year

mutualism

Mutualism is a relationship that benefits both species; these benefits can be in dispersing pollen and seeds for reproduction, in receiving food, or in receiving protection. Mutualism is not cooperation; each species exploits the other.

natural selection and artificial selection

NS: can lead to development of an entirely new species; occurs when members of a population have genetic traits that improve their ability to survive and produce offspring with those specific traits AS: crossbreeding between genetic varieties of the same species to give rise to populations with desirable traits. Now, scientists can use genetic engineering to produce desirable traits or eliminate undesirable ones

Environmental resistance

factors that limit population growth

American alligator case study

Alligators act as a keystone species, yet their numbers were seriously compromised by over-hunting. Their activities provide important habitat for fish and avian species. They also control populations by their feeding behaviors. In 1967 the alligator was placed on the endangered species list and has made a dramatic recovery.

reserouce partitioning

Species may use only parts of resource At different times In different ways

Logistic growth

Population faces environmental resistance

species diversity

number and abundance of species present in different communities

Endemic species

(those found in only one place) are especially vulnerable

How do geological processes and climate change affect evolution?

A. Processes such as the shifting of tectonic plates, volcanic eruptions, and earthquakes influence earth's climate and in turn affect evolution by removing and/or isolating habitats and species. B. Long-term climate changes relocate ecosystems, thus determining where certain species can live. C. Asteroids and meteorites have caused environmental stress and mass extinctions.

What is species diversity and why is it important?

A. Species diversity is the number of species (richness) combined with their relative abundance (evenness). B. Species rich communities tend to be more stable and more productive.

Exponential growth

At a fixed percentage per year

functional diversity

Biological and chemical processes or functions such as energy flow and matter recycling needed for the survival of species, communities, and ecosystems

Threats to Kelp Forests

Giant kelp forests are very productive and biologically diverse ecosystems. Sea urchins are a major threat to kelp, but sea otters keep their populations in check. Polluted water and the warming of the world's oceans also threaten kelp forests. If kelp forests decline significantly, many other species could be affected.

How Did Humans Become Such a Powerful Species?

Humans have thrived so well as a species because of their strong opposable thumbs, ability to walk upright and complex brain. These adaptations may not prove as beneficial as the environment continues to change, though our powerful brain may allow us to live more sustainably in the future.

5 basic types of interactions

Interspecific Competition Predation Parasitism Mutualism Commensalism

what limits the growth of populations?

No population can grow indefinitely because of limitations on resources and because of competition among species for those resources

Mutualism

Nutrition and protective relationship Gut inhabitant mutualism Not cooperation - mutual exploitation

predator/prey relationships

Predators have a variety of ways to capture prey. Herbivores feed on immobile plant species; carnivores use pursuit of prey or ambush to capture prey. Some predators use camouflage, and others use chemical warfare (venom) to capture prey or deter predators. 4. Prey species escape predators in a number of different ways such as swift movement, protective shells, camouflage, or use of chemicals to repel or poison.

When a Population Exceeds Its Carrying Capacity

Reproductive time lag may lead to overshoot; can produce a dieback/crash of organisms unless the organisms can find new resources or move to an area with more resources. Damage may reduce area's carrying capacity

List six factors that contribute to the threats of extinction for frogs and other amphibians. What are three reasons for protecting amphibians?

Six factors: o Habitat loss o Drought o Increases in UV radiation o Parasites o Viral and fungal diseases o Pollution Three reasons: o They are indicator species. o They control insect populations. o They are a storehouse of pharmaceutical chemicals.

commensalism

Some species interactions help one species but does nothing for the other; this is commensalism Benefits one species and has little affect on the other Epiphytes Birds nesting in trees

species reproductive patterns

Some species: - Have many small offspring - Little parental involvement - spiders Other species: - Reproduce later in life - Have small number of offspring - pandas

How do communities and ecosystems respond to changing environmental conditions?

The structure and species composition of communities and ecosystems change in response to changing environmental conditions through a process called ecological succession The classic view of ecological succession is that it is an orderly sequence, each stage leading to the next, more stable stage until a climax community is reached. Such a community would represent the balance of nature, one dominated by a few long-lived plant species that is in balance with its environment. C. Changes in environmental conditions that disrupt a community can set back succession. D. Living systems are sustained through change.

Range of tolerance

Variations in physical and chemical environment Individuals may have different tolerance ranges

extinction

When population members cannot adapt to changing environmental conditions When local environmental conditions change, some species will disappear at a low rate; this is called background extinction. Mass extinction is a significant rise in extinction rates above the background extinction level. Usually, 25-95% of species are lost. There appear to have been at least three and perhaps five mass extinctions on the earth.

Exploding White-Tailed Deer Populations in the United States

White tailed deer populations were in decline 100 years ago, due to habitat loss and hunting. Subsequent protection and decline in their natural predators led to a drastic increase in their numbers to the extent that they have become a nuisance and even a danger on the urban edge. Efforts to control their populations are very complicated, and in many cases expensive.

predatation

a member of one species (the predator) feeds directly on all or part of a member of another species (the prey). An example is lion to deer. In predation, a member of one species (the predator) feeds directly on all or part of a living organism of another plant or animal species (the prey) as part of a food web. Together, the two different species—such as lions (the predator, or hunter) and zebras (the prey, or hunted)—form a predator-prey relationship keeps prey population sizes smaller

Three common misconceptions about evolution

a. Fitness is a measure of strength. b. Organisms develop certain traits because they need them. c. Evolution works according to some grand plan.

Resilience

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

ecological succession

gradual change in species composition of a given area an orderly sequence, each stage leading to the next, more stable stage until a climax community is reached. Such a community would represent the balance of nature, one dominated by a few long-lived plant species that is in balance with its environment. C. Changes in environmental conditions that disrupt a community can set back succession.

Primary ecological succession

gradual establishment of biotic communities on lifeless ground. in lifeless areas

keystone species

have a large affect on maintaining balance within an ecosystem

importance of sea otters

help to generate millions of dollars a year in tourism income in coastal areas where they are found biologists classify them as a keystone species. Without southern sea otters, scientists hypothesize that sea urchins and other kelp-eating species would probably destroy the kelp forests and much of the rich biodiversity associated with them

Parasitism

live on or in another species. The host of this arrangement is obviously harmed by it, but the parasite can contribute to biodiversity by controlling the size of specific species populations. Parasite is usually much smaller than the host Parasite rarely kills the host Parasite-host interaction may lead to coevolution

specialist species

narrow ecological roles

species

set of individuals who can mate and produce fertile offspring 8 million to 100 million species About 2 million identified Unidentified species are mostly in rain forests and oceans

evolutionary adaptions

some species evolve adaptations that reduce/avoid competition for resources. 1. Over a long time, species evolve more specialized traits that allow them to use shared resources at different times, in different ways, or in different places; this is termed resource partitioning.

Ecological niche

species' way of life in an ecosystem - everything that affects its survival and reproduction; can be occupied by native or non-native species

speciation

two species arise from one when some members of a population cannot breed with other members to produce fertile offspring. Speciation occurs in two phases: 1. Geographic isolation: physical separation for long time periods 2. Reproductive isolation

genetic diversity

variety of genetic material within a species or population

biodiversity

variety of species, genes, ecosystems, and ecosystem processes

ecological diversity

variety of terresterial and aquatic ecosystems found in an area or on the earth

coevolution

when predator and prey can exert intense natural selection pressures on one another. Interact over a long period of time Changes in the gene pool of one species can cause changes in the gene pool of the other Bats and moths Echolocation of bats and sensitive hearing of moths