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In the previous chapters, we looked at individual organisms and how they solve life's many problems.
Let's discuss how organisms deal with their environments.
Organisms interact with their environments.
The behavior of the organisms is affected by the environmental stimuli.
This is important for reproducing as efficiently as possible while using the least energy.
Smaller animals have a slower metabolism per unit mass than larger animals.
The tissue from a small animal would have a higher rate of metabolism than the tissue from a large animal.
Excess energy can be used to grow and store energy.
When they are deficient, they use up their stores and die.
Animals respond to their environment by their body temperature.
Animals that generate their own heat through metabolism are called endotherms.
There is no internal mechanism to control body temperature.
They look for cool or warm places to regulate their temperature.
A lizard is on a rock.
Communication is a big part of behavior.
It's important that members of the same species coordinate their behavior.
Animals use a variety of signals to find food, establish territory, and reproduce successfully.
Communication is important between different species.
Some animals behave in a certain way, while others do not.
Humans can do both.
To pass the AP Biology Exam, you'll need to know how organisms cope with their environments.
Instinct is a learned behavior.
Environmental signals called releasers can cause instinctive behavior.
A small part of the environment is perceived as the releaser.
The sight of a tuft of red feathers on the male is a releaser that causes fighting behavior.
Instinct can be thought of as the circuitry that guides behavior.
Hive insects, such as bees and termites, are born knowing their roles.
The honey bee dances to communicate location of food to other members of the hive.
Natural selection favors certain behaviors.
Some of the behaviors are instincts.
Many learned behaviors are essential for survival, indicating that the ability to learn might be a trait that is naturally selected for.
There are other types of instincts that are gradually replaced by "learned" behavior.
Human infants have an ability to suck from a nipple.
The infant would starve if it weren't for this behavior.
The infant will learn to feed itself once it moves beyond this instinct.
The "circuitry" that directs and guides behavior is Instinct.
Learning is another form of behavior.
Learning is a change in a behavior brought about by an experience.
There are a number of ways animals learn.
The goslings recognize the call the mother gives them.
The goslings hear the call and follow their mother around until they are big enough to head out on their own.
Imagine the same goslings.
They will accept the first moving object they see as their mother if the mother isn't there.
This process is called imprinting.
Within a few days after birth, animals are able to recognize their own species.
A window of time when the animal is sensitive to certain aspects of the environment is when different types of imprinting occur.
Imprinting is a form of learning that takes place during a brief period of time.
Habituation is a form of learning.
An animal learns not to respond.
If an animal encounters a stimuli over and over again without consequences, the response will gradually diminish and disappear.
If a certain hallway always smells weird, you will notice at first but eventually learn not to notice it.
Learning has modified the basic response.
You will notice it if you walk down a new hallway.
Both animals and plants have other instinctual behaviors.
The first thought that comes to mind is that they've seen the sun.
Many people crow before the sun rises.
The roosters have internal alarm clocks.
Plants have them as well.
The internal clock, or cycles, are known as circadian rhythms.
The word circle is similar to the rhythms that have a circular nature.
Seasonal changes, like the loss of leaves by trees, are not examples of the rhythms of the body.
Think about how bad jet lag would be if you traveled around the world.
circling the globe messes with your rhythm.
If you've traveled overseas, you know about the rhythms of the sun and moon.
Jet lag is caused by them.
Our watches tell us it's one time, while our bodies tell us it's another.
You don't need to know how to tell time in order to feel jet lag.
Some animals use signals to communicate.
These signals are often used to influence social behavior.
Chemical signals are used for communication among animals.
Pheromones are chemical signals between members of the same species that affect behavior.
Female insects attract males from great distances when they give off their pheromones.
The behavior observed among members of a species is influenced by visual signals.
Firefly produce flashes that can be seen far away.
The flashes help male and female fireflies locate each other in the dark.
Animals use electrical channels to communicate.
Other people use signals from their skin to detect prey.
Cave-dwelling fishes use their skin for communicating and detecting prey.
Many animals interact with each other in complex ways.
Social behaviors can help members of the species.
Competition for food or other resources can lead to aggressive behavior.
Animals show aggression towards other members that use the same resources.
A fight among competitors is an example of agonistic behavior.
pecking orders are when a group establishes which members are the most dominant.
The leader of the group will usually be a male who has the best pickings of food and females.
Competition and tension within the group are reduced once the dominance hierarchy is established.
Territoriality is common when there is a shortage of food.
In order to protect important resources, the male of the species usually establishes a home range within a group.
This behavior is found in birds.
Altruistic behavior is a type of behavior that benefits another group at the expense of the individual.
When a ground squirrel gives a warning call, it puts itself at risk of being found by a predator.
These include remoras, which attach themselves to the backs of sharks, and lichen, which grows on rocks.
Lichen appears to be one organisms, when in fact it is two organisms--a fungus and a alga--living in a complex symbiotic relationship.
Thebacteria can perform photosynthesis.
They do not have the organelles.
There are protists that can perform photosynthesis.
There are many different types of relationships between multicellular organisms and unicellular organisms.
Many mammals have organisms living inside of them.
There is a mutualistic relationship between us.
Humans and other mammals help us in many ways by giving us a nice home and helping us make things.
It's good that we have goodbacteria because otherwise we might get sick from them.
Most interactions are done to get more energy.
This can be done by gaining resources or by doing something that is more efficient.
Plants have evolved ways to respond to their environment.
The plant behaviors covered on the exam are called photoperiodism and tropisms.
Plants flower when there is more daylight and less darkness.
This is called photoperiodism.
Plants flower according to the amount of darkness and not the amount of sunlight.
Plants need light.
The movement of plants toward the light is known as phototropism.
Plants grow up and down, with the branches growing upward and the roots falling into the soil for water.
The tendency to grow away from the earth is called gravitropism.
All of the tropisms are examples of plant behavior.
A turning in response to aStimulus is called a tropism.
Plants have three basic tropisms.
Plants bending toward light is referred to as phototropism.
Plants respond to gravity in different ways.
Stems grow away from the pull of gravity, whereas roots grow downward into the earth.
The way plants respond to touch is referred to as Thigmotropism.
The responses are initiated by hormones.
The major plant hormones are in a class called auxins.
Plants have auxins that serve many functions.
Growth can be promoted on one side of the plant.
In phototropism, the side of the plant that faces away from the sunlight grows faster because of the plant's auxins.
The tip of the plant is where most growth occurs.
Auxins are involved in fruit development.
The hormones that regulate the growth and development of plants are gibberellins.
Plants are an example of how important cell communication is to organisms.
Plants are able to grow, develop, survive, and adapt to environmental cues through the use of hormones.
They function using signal transduction.
Similar to what happens in animal cells, these cell communication pathways are similar.
The study of interactions between living things and their environments is known as ecology.
We've spent most of our time talking about individual organisms.
In the real world, organisms are interacting with other organisms and the environment.
The best way to understand the various levels of ecology is to progress from the big picture, the biosphere, down to the smallest ecological unit, the population.
The world of ecology has a hierarchy.
There is a part of the earth where living things exist.
Light, water, and air are included.
The total mass of the earth is larger than the biosphere.
The biosphere can be divided into large regions.
Biomes are massive areas that are classified on the basis of their climates and plant life.
tundra, taiga, deciduous forest, grassland, deserts, and tropical rainforests are some of the major biomes.
It's important to remember that the biomes tend to be arranged along certain latitudes.
If you hiked from Alaska to Kansas, you would pass through tundra, taiga, deciduous forests, and grassland.
Both living and non living factors are included in the ecosystems.
A lake, its surrounding forest, the atmosphere above it, and all the organisms that live in or feed off the lake would be considered an environment.
Living factors and non living factors are called abiotic factors.
Abiotic factors include water, humidity, temperature, soil/atmosphere composition, light, and radiation.
You probably know that there is an exchange of materials.
On the next page, you can see the flow of carbon through an environment.
The carbon cycle is how carbon is recycled.
In other words, carbon moves through the environment.
Nitrogen and water have cycles.
Balance of the environment is dependent on the interactions between the biotic and abiotic factors.
The community is the next level.
A group of interacting plants and animals are referred to as a community.
You, your dog, and the fleas on your dog are all part of the same community.
There is a niche for each organisms position or function in the community.
Two organisms will compete for resources in the same niche.
A species will usually thrive without competition if it can occupy an empty niche.
The food chain shows these connections.
Different organisms depend on one another for food.
The food chain has four levels: producers, primary consumers, secondary consumers, and tertiary consumers.
All of the raw building blocks are used by autotrophs to make their own food.
From water and the gases that abound in the atmosphere and with the aid of the sun's energy, photosynthetic autotrophs convert light energy to chemical energy.
This is accomplished through the use of photosynthesis.
The rate at which autotrophs convert light energy into chemical energy is called primary productivity.
The gross productivity can't be measured because cell respiration is happening at the same time.
Net productivity only takes into account organic materials that are left over after organisms take care of their own energy needs.
Oxygen production in the light is used to calculate this.
The equation for this relationship is listed on the sheet.
There is a group of autotrophs that are chemosynthetic and can take up resources from their surroundings and make their own energy.
All of the food is produced by autotrophs.
The first trophic level is made up by them.
They have the highest number of organisms and the highest total weight.
Heterotrophs are forced to find their energy sources outside of the world.
Heterotrophs digest their prey into carbon, hydrogen, oxygen, and nucleic acids.
Heterotrophs get their energy from the things they consume.
Primary consumers feed on producers.
A cow is a good example.
The organisms are also known as herbivores.
The second trophic level is made up by them.
The organisms that feed on primary consumers are the next level.
The third trophic level is made up of the secondary consumers.
tertiary consumers are above these.
All organisms have to give up at some point.
The organisms that break down organic matter are called decomposers.
They are the decomposers.
They collect garbage in our environment.
A food chain has a linear network of links.
A food web shows many paths that connect plants and animals.
Producers make their own food.
Primary consumers and producers are eaten by secondary consumers.
All of the above are eaten by tertiary consumers.
Composers break things down.
Sometimes a single organisms is important.
Maybe it is the only thing that keeps a predator in check.
keystone species are important species.
The entire balance can be undone very quickly if a keystone species is removed.
The 10% rule refers to the amount of energy transferred from one level to the next in a food chain.
This energy is turned into heat.
Primary consumers have less energy than producers, secondary consumers have less energy than producers, and tertiary consumers have less energy than producers.
The idea about energy is not applicable to individuals.
If you add up all the members at that level, the level has less energy.
In an ecological pyramid, the energy flow, biomass, and number of members are represented.
Organisms that are higher up on the pyramid are less efficient.
When consumers at the top eat something beneath them, it is like they are eating the same thing over and over again.
If there is a toxin in the environment, the consumers at the top are getting the most of it because it becomes more concentrated at each level.
Animals further up the pyramid are more likely to be killed by toxins in the environment.
The animals at the top of the pyramid are most likely to be affected by a toxin.
The concentration of toxins is increasing.
The classic example of this phenomenon is the use of pesticides to kill mosquitoes.
The large-scale spraying of DDT resulted in a decrease in the mosquito population, but it also resulted in the death of ospreys.
Dichlorodiphenyltrichloroethane is also known as DDT.
The birds of prey are mostly fish.
The fish that ospreys consumed had been contaminated with insects.
The toxins grew more concentrated because fish eat thousands of insects.
The near extinction of certain osprey populations was caused by the insecticide.
The eggshells of ospreys were weakened by sufficient concentrations of DDT.
Eggs broke before they could hatch, killing unborn ospreys.
A disruption in one level due to environmental changes affects all other levels of the system.
There are environmental tragedies that still occur.
Major changes at all the other levels are invariably the result of a change in one level.
There is a precarious balance to the ecosystems.
There are many things that can disrupt the balance.
The surrounding levels will be affected if the level changes.
There are many things that can disrupt the balance.
The balance of the environment can be disrupted by invasive species.
They have no natural predator or competition and soon take resources from other species.
Extreme events are more likely to be resistant to a diverse community.
Simpson's Diversity Index is a measure of the community's diversity.
Population ecology studies how populations change.
Whether these changes are long-term or short-term, predictable or unpredictable, we're talking about the growth and distribution of a population.
To study a population, you need to look at four things: the total number of individuals, the density, the distribution patterns, and the age structure.
The graph below shows that young oysters have a high death rate, but those that survive do well.
There is a low death rate among the young of humans, but after 60 the death rate is high.
The number of births minus the number of deaths is called population growth.
The carrying capacity is the maximum number of individuals that a habitat can support.
Most populations don't reach their carrying capacity because they're exposed to limiting factors.
Population density is an important factor.
Density-independent or density- dependent are the factors that limit a population.
The density of the population does not affect the population.
Extreme climates and severe storms are examples.
Density- dependent factors have effects that depend on population density.
Resource loss, competition, and predator are all examples of density dependent factors.
As the population density increases, the effects become even more intense.
Population growth rates vary greatly.
Logistic growth and exponential growth are the two types of growth.
The AP Biology Equations and Formulas sheet has equations for both.
When a population is in an ideal environment,ential growth occurs.
There are lots of resources, space and no disease in the area.
This is an example of rapid growth.
The curve arches upward.
A J-shaped curve is created by rapidential growth.
The initial growth ofbacteria in a culture is an example of exponential growth.
They multiply quickly because there's plenty of room and food.
As the population increases, the individualbacteria begin to compete with each other for resources.
The curve levels off when the population reaches its carrying capacity.
When the population size approaches the carrying capacity, the growth rate approaches zero.
The population is restricted because of limited resources.
Logistic growth is what this is referred to as.
On the previous page, you can see that the growth forms an S-shaped curve.
There are two types of life-history strategies: r-selected species and k-selected species.
R-strategists thrive in areas that are barren.
They reproduce as quickly as possible once they colonize an area.
Producing lots of offspring is the best way to ensure survival.
Common weeds, dandelions, andbacteria are examples.
The k-strategists are at the other end of the spectrum.
Stable environments are best suited for these organisms.
Elephants are large animals with long lifespans.
Unlike r-strategists, they don't produce many offspring.
Competition from other organisms is usually not a problem for k-strategists.
Communities of organisms don't just come up on their own, they develop over time.
If you look at the enormous stretches of time over which evolution occurs, hundreds of thousands or even millions of years, you'll see that it is pretty short.
Primary succession is the process of ecological succession in which no previous organisms have existed.
The community of lichens is where the first stage of the job usually begins.
Lichens are hardy.
Over time, they can erode the rock surface and turn it into soil.
Lichens are considered pioneers.
The stage has been set for other organisms to settle in when the area has been made more hospitable by lichens.
In an orderly fashion, communities are established.
Lichens are replaced by mosses and ferns, which in turn are replaced by tough grasses, low shrubs, evergreen trees, and, finally, deciduous trees.
They can't compete with the new plants for sunlight and minerals.
The entire sequence is called a sere.
The climax community is the final community.
The climax community is stable.
Deficiency trees are part of the climax community.
The events occur much more quickly than the principles apply.
The first invaders are usually grasses, shrubs, saplings, and weeds.
Secondary succession occurs when a new community develops where another community has been destroyed or disrupted.
Events such as fire, tornado, or human impact can clear the existing community.
The impacts leave the soil intact.
The results are far-reaching because humans have disturbed the existing ecological balance.
Various forms of pollution have increased.
There are potential consequences on the environment.
Burning fossil fuels and forests have contributed to the warming of the earth.
Warming may cause polar ice caps to melt.
Changes in precipitation patterns, plant and animal populations, and changes in agriculture are possible effects of global warming.
Ozone depletion is caused by pollution and the use of chlorofluorocarbons, which are used in aerosol cans.
Ozone protects the earth's surface.
It could increase the incidence of cancer.
Burning fossil fuels causes pollution such as sulfur dioxide and nitrogen dioxide.
These compounds form sulfuric and nitric acids when they react with clouds.
Acid rain is the rain that falls from these clouds.
Acid rain damages water systems, plants, and soil.
Changing soil pH can damage plant roots and stunt their growth.
Useful microorganisms that release nitrogen from decaying organic matter into the soil are also killed.
Low pH kills fish that have just hatched.
Desertification occurs when the land is overgrazed by animals.
Changes in weather patterns and erosion can occur when forests are cleared.
Toxic chemicals are a concern in the environment.
The pesticide is used to control insects.
After it was found to damage plants and animals, the pesticide was stopped.
Even though it resists chemical breakdown, it can still be found in living organisms.
As each trophic level consumes DDT, the substance becomes more concentrated by the process of biomagnification.
Many plants and animals have become extinct due to the destruction of habitats.
Some of the plants could have provided us with some beneficial products.
Humans spread diseases when they travel and disrupt habitats.
All living things can be devastated by these diseases, which act as immediate pressures on the landscape.
Acid rain, pollution, soil erosion, and depletion of the ozone layer are just a few of the problems afflicting the environment today.
A response to the environment is called behavior.
Social behaviors include agonistic behavior, dominance hierarchies, territoriality, and altruistic behavior.
tropisms are plant-specific behaviors.
There are three basic tropisms.
There are several major biomes that make up the biosphere.
The ecosystems are contained in each biosphere.
One of the main roles of the organisms within the community is to convert light energy to chemical energy via photosynthesis.
The 10% rule says that only 10% of the energy consumed from one level will be retained by the higher level.
Normal daily activities will be performed with the other energy.
The population is the smallest unit of ecology.
The carrying capacity is the maximum number of individuals that can be supported by a habitat.
Density-independent factors and density- dependent factors are factors that affect carrying capacity.
When a population is in an ideal environment, exponential growth occurs.
Logistic growth occurs when there are limited resources in an environment.
R-strategists and k-strategists are the two main types of organs.
R-strategists produce lots of offspring.
K-strategists, which are usually large animals, produce few offspring but have longer life spans and less competition for resources.
Succession describes the way in which a community recovers after a disruption.
Chapter 15 contains answers and explanations.
A primate is trying to reach a bunch of bananas suspended from the ceiling by stacking boxes on top of each other.
Viruses require their host cells to replicate.
Viruses try to reproduce as quickly as possible in a host.
There is a graph depicting the growth pattern of a bug.
In a pond, spring rains can cause an expansion of species in the food chain.
Runoff from nearby hills causes an algae bloom when combined with warming temperatures.
plankton's population expands by eating the algae.
These plankton are eaten by small crustaceans, which then become prey for fish.
The table, chart, and paragraph are referred to in questions 3-6.
The average pH in Richard Creek changed from 1980 to 2000.
An ecological survey was performed to evaluate the effect of decreases in pH on the aquatic life of the creek.
Four times a year, ecological surveys were performed to identify the number of snails, crayfish, and brook trout present at different locations.
The percent change is shown in a chart.
Many aquatic organisms can't live in low pH environments.
Table 1 shows the minimum pH necessary for common aquatic organisms to survive.
When you touch the leaves of the plant, they immediately close up.
The purpose of this type of movement is one theory.
The vegan diet is the only way to reduce your carbon footprint, with respect to food, because it cuts your carbon footprint in half, according to a post written by a proponent of the diet.
Costa Rica has a lot of beautiful tropical rainforests.
Cattle farmers used to clear the forests for their animals.
In recent decades, the government has placed more emphasis on the environment.
The fields are being reclaimed.
There is a dense shrubbery along the edge of the field.
In humans and livestock, yeast or beneficialbacteria are applied to maintain health.
These organisms help in the digestion of food.
These organisms have protective effects.
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