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AP Biology Review (Part Four)
AP Daily 8.1 - Responses to Environment
How do organisms respond to changes in their environment?
Organisms respond to changes in their environment through __behavio__r and physiological mechanisms
What is a stimulus?
Stimulus: an external or internal signal or combination of signals that causes a response from an organism
What is a signaling behavior and what does it produce?
Information exchanged between organisms with one another in response to internal and external signals
Produce changes in behaviors of other organisms
Can result in differential reproductive success
List five types of communication mechanisms used in animals.
Visual
Audible
Tactile
Electrical
Chemical signals
List four uses of these communication mechanisms.
Indicate dominance
Find food
Establish territory
Ensure reproductive success
Natural selection favors the behaviors that increase survival and reproductive success.
Explain the difference between innate and learned behavior.
Innate behaviors are genetically controlled and can occur without prior experience or training
Learned behaviors are developed as a result of experience
What is a cooperative behavior? Why do organisms use cooperative behaviors?
Cooperative behavior: Involve teamwork between organisms of the same species
It i__ncreases the fitnes__s of the individual
Increases the survival of the population
What is aposematism? Give two examples.
Aposematism: Evolved warning traits used to discourage predation
Can be markings, behaviors, and/or chemicals
Coral snakes: have distinct red, yellow, black banding that indicates presence of venom to potential predators
Skunk arching their backs + raising tail + turning back + stomp feet before spraying
How do mammals establish territories?
Use scent markings to establish and identify territory
Urine, feces, secretions from scent glands
Can contain pheromones
Can communicate social status/ownership + warm off competitors
Can be used to attract females
Explain how behavior can influence species distribution.
Behavior can influence species distribution in the way organisms or a population respond to stimuli to increase fitness in an environment as they can now survive better in those conditions.
List and describe the different ways that organism exchange information with other organisms
Organisms can exchange information with other organisms in visual, audible, tactile, electrical, and chemical signals to increase the survival and reproductive success which is favored through the environment’s natural selection as well as indicating dominance, finding food, establishing territory, and ensuring reproductive success.
Explain how an organism's behavioral response affects its overall fitness
An organism’s behavioral response affects its overall fitness by allowing the organism to develop innate, learned, and cooperative behavior to overcome selective pressures from the environment such as the competition for food, indicating dominance, etc.
Compare and contrast Innate, Learned, and Cooperative behaviors.
Innate behaviors occur without experience, while learned behaviors develop as a result of the experience and the pressures from the environment, and lastly cooperative behaviors is teamwork between a population to increase fitness and survival
AP Daily 8.2 Energy Flow Through Ecosystems
How do endotherms maintain body temperature?
They use thermal energy generated by metabolism to maintain homeostatic body temperatures
Ex. change in heart rate, fat storage, muscular contractions (shivering)
How do ectotherms maintain body temperature?
They lack efficient internal mechanisms to regulate and maintain body temperatures
Rely on behaviors to regulate temperature
Ex. moving in or out of the sun
What is metabolic rate?
Metabolic rate: amount of energy expended by an animal over a specific amount of time
What is the relationship between metabolic rate and the size of the organism?
The smaller the organism, the higher the metabolic rate
A net gain in energy can result in energy storage or growth; a net loss in energy can result in loss of mass or death
Organisms that produce many offspring at a time (r-selected) are less energy-efficient and tend to be in unstable environments. (where resources not readily available/environment experiences frequent changes)
Organisms that produce few offspring at a time (K-selected) are more energy-efficient and tend to be in stable environments.
What is a trophic level?
Changes in energy availability can results in changes in population size and result in disruptions to an ecosystem
Change in producer level can affect the number and size of other trophic levels
Trophic level: position an organism occupies in a food chain
What do food chains show?
Food chain: The direction of nutrient and energy transfer from one organism to another
Each organism occupies a different trophic level and reflects how many energy transfers separate it from the producer
Ex. primary producer>primary consumer>secondary consumer>tertiary consumer>quaternary (apex) consumer>decomposer
What is a food web?
Food webs: consist of many interconnected food chains
The transfer of energy between trophic levels is inefficient
Typically around 10%
The energy inefficiency limits the length of food chains and the size of populations
Population size decreases as you go up trophic levels.
Explain the differences between the two types of autotrophs.
Autotrophs: organisms that capture energy from physical or chemical sources in the environment
Photosynthetic organism capture energy present in sunlight
Chemosynthetic organisms capture energy from small inorganic molecules present in their environment with/without oxygen
Where do heterotrophs get energy?
Heterotrophs capture energy present in carbon compounds produced by other organisms
Metabolize carbohydrates, lipids, proteins as sources of energy hydrolysis (adding water to break down)
Compare and Contrast endotherms and ectotherms in an ecosystem.
Endotherms use thermal energy generated by metabolism to maintain homeostatic body temperatures while ectotherms have to rely on behaviors to do the same
Describe how metabolic rate impacts an organism’s overall ability to live.
It is the amount of energy expended by an animal over a specific amount of time so when there is a net gain in energy, it is beneficial for the organism's ability to live as it results in energy storage or growth; on the other hand, the over expenditure can result in the loss of mass or death which decreases an organism’s overall ability to live
Construct a T-Chart between the two reproductive strategies in response to energy availability.
R-Selected | K-Selected |
|---|---|
Organisms produce many offspringLess energy efficientIn unstable environments | Organisms produce few offspringMore energy efficientTend to be in stable environments |
Explain why population size decreases as the trophic level increases
Because the transfer of energy between trophic levels is inefficient (10%) so it limits the length of food chains
Draw and Illustrate the difference between a food chain and a food web.
It is said that energy flows through ecosystems, while matter is recycled. Describe how the relationships demonstrated in food webs illustrate this idea.
10% of the energy travels up each trophic level and is at the end decomposed and “recycled” by decomposers who break down the organism and provide nutrients to the soil for the primary producer to use
Distinguish the difference between the two types of autotrophs
Photosynthetic organisms capture energy from sunlight while chemosynthetic organisms capture energy from small inorganic molecules
Explain why delayed implantation of eggs in the uterus of females Grizzly bears is a successful strategy
It is dependent on the conditions of the environment and if the bear was able to accumulate enough fat- so if the bear does not gather enough fat, it will not be able to reproduce and preserves energy to live (k selected species)
AP Daily 8.3 Population Ecology
What is a population?
Population: comprised of organisms of the same species in a particular area
Individuals interact with one another and with the environment in complex ways
Individuals within a population usually interbreed with one another more than interbreeding with individuals from other populations
The size of a population largely depends on availability of resources
How does food availability affect reproduction and survival rates?
When food is less available, the population size decreases
Less food energy is available to support individuals
Reproduction rates decrease
Offspring survivability decreases
When food is readily available, the population size increases
Reproduction rates increase
More food for offspring
Survival rates increase
What are some adaptations that aid in survival when energy availability decreases?
Storage of fat during winter months
Losing leaves or growing leaves when day length changes
Migrating in response to change in food availability
List some factors that affect population growth.
Age at reproductive maturity
Number of offspring produced
Frequency of reproduction
Survivorship of offspring to reproductivity maturity
Population Growth Equation 
dN= change in population size
dt= change in time
B= birth rate
D= death rate
If B > D the population growth rate will grow, if B < D the population growth rate will decrease
What conditions lead to exponential growth?
Exponential growth: refers to a sharp increase in the growth of a population
Occurs under ideal conditions, when resources are abundant
The number of organisms added in each generation increases as the population gets larger
More individuals are reproducing
How long it takes to produce an offspring stays the same
What would a graph of the population size in a population experiencing exponential growth look like? 
J-shaped curve
dN= change in population size
dt= change in time
N= population size
R max = maximum per capital growth rate of population
What would a graph of the population size in a population experiencing logistic growth look like?
Stop the video at 3:04. What is the growth rate of the population in the question? Show your work.
dN/1=500-75> dN=425
425/1=rmax (2500)
0.17=rmax
Describe the relationship between energy availability and population size.
When there is more energy available, the population size with increase with more energy used for reproduction and other organism processes
Explain how limiting factors in a population lead to natural selection.
Limiting factors will cause a population to stop growing after the environment’s carrying capacity, and once that is reached natural selection will act upon the population with an increase in competition for resources required for the population to survive
Describe exponential growth of a population
Exponential growth occurs when the growth rate the entire time so the population grows faster and faster until it reaches the carrying capacity that will limit resources with the pressure from the extra amount of organisms
Draw and Illustrate in a graphical manner the exponential growth of a population.
Distinguish the parts of the exponential growth equation
dN/dt= rmax * N
dN= change in population size
dt= change in time
N= population size
R max = maximum per capital growth rate of population
Practice the exponential growth equation using the mice population from the video. Show your work.
dN/1=500-75> dN=425
425/1=rmax (2500)
0.17=rmax
AP Daily 8.4 Effect of Density of Populations
What is population density?
Population density: refers to how close individuals within a population live near one another
How does food availability affect population density?
When an abundance of food is available, the population can become dense
Higher reproductive rate
Space is limited
When food is limited, the density of a population may decrease
Lower reproductive rate
Individuals can spread out in the limited space
What are density dependent factors. Give two examples.
Density-dependent factors: abiotic or biotic factors whose effect on population size relies on a population’s density
Competition; Territoriality; Disease; Predation
What are density independent factors. Give two examples.
Density-independent factors: abiotic or biotic factors that affect population size regardless of population density
Natural disasters: floods; forest fires; volcanic eruptions
pollution
What are the three stages of growth shown in the logistic growth curve?
Logistic-growth model: describes population growth that initially starts slowly, immediately followed by exponential growth, and ends with a relatively stable maximum growth
What would a graph of population size in a population experiencing logistic growth look like?
Illustrated as an S-shaped curve
What is carrying capacity?
Carrying capacity: maximum number of individuals an environment can sustain
What causes a population to reach carrying capacity?
Both density-independent and density-dependent limiting factors can cause a population to reach carrying capacity
Limiting factors will always bring population size back down
Fluctuations in population size can naturally occur at or near carrying capacity
Write the equation for logistic growth here. How does dN/dt change as N gets closer to K?
dN= change in population size 
dt= change in time
N= population size
K= carrying capacity
Rmax = maximum per capita growth rate of population
Stop the video at 3:18. What is rmax? Show your work.
75=rmax(150)(275-150/275)
75/68.1818= rmax
rmax= 1.10
Explain the difference between density-dependent and density-independent limiting factors. Discuss which of the two have the greatest immediate impact on a population
Density-dependent is when a population size is dependent on the population density while density-independent is when a population not affected by the denn\sity and can have the greatest immediate impact such as a natural disaster
The Allen High School campus is a small ecosystem. Describe 3 biotic factors that exist here, and 3 abiotic factors that exist. Explain how the abiotic factors influence the biotic factors. NOTE: For purposes of this question, students do not count as biotic factors since you do not reside on campus. ☺. and why.
3 biotic factors that exist in Allen High School include bacteria, plants on the outside of the school, . Abiotic factors such as temperature, sunlight, and air circulation affects the growth of plants and bacteria so when they are abundant, the biotic factors will be able to survive better
Draw a non-verbal representation of how changes in abiotic and biotic factors affect various populations.
Explain how exponential growth of a population in a logistic-growth model is halted by the carrying capacity of an ecosystem.
It is halted by the carrying capacity of an ecosystem as the increased population will place pressure on the resources and cause intraspecific competition to decrease the population around the carrying capacity
Distinguish the parts of the logistic growth equation
dN= change in population size
dt= change in time
N= population size
K= carrying capacity
Rmax = maximum per capita growth rate of population
Practice the logistic growth equation using the bird population from the video. Show your work.
75=rmax(150)(275-150/275)
75/68.1818= rmax
rmax= 1.10
Describe the limiting factors that prevent many populations from reaching their carrying capacities.
If there is less food available, it decreases the population because there will be a lower reproductive rate more pressure on other resources
AP Daily 8.5 Community Ecology
What is a community?
Community: a group of different species living together in the same location and interaction with one another
How do we describe communities?
Based on species diversity and species composition
How is species diversity different from species composition?
Species diversity: variety of species and quantity of individuals in each species within a given community
Species composition: identify of each species in a community
The Simpson’s Diversity Index measures the biodiversity of a habitat. Higher SDI values mean the community is more diverse.
Based on random samples of the environment
(# of each of the individual species/total)^2 and continue for each species and add up to get sum and subtract value from 1
Closer to 1= more diverse
Competition can occur within or between species
Can result in change in community structure
Competition for food and habitats
Interactions between organisms can be positive*,* negative or neutral
Describe two examples of positive interactions between species.
Mutualism: both species benefit (+/+)
ox/bird: bird gets food source from parasites, ox is getting cleaned
Commensalism: one species benefits but the other is not harmed or helped (+/0)
Describe two examples of negative interactions between species.
Predator-prey: one species uses another for a f__ood source__
Pride of lions eating giraffe
Parasitism: one species benefits at the harm of another (+/-)
Describe one example of a neutral interaction between species.
Deer and rabbits in same forest, do interact but not competing
Why is the interaction between shelf fungi and trees considered negative? What positive effects on the community could it have?
They are tree parasites
They produce flirting bodies that grow on the bark of the tree
They absorb nutrients from the outer bark of the tree
Leads to weakening of the external structure of the ree
Reduces canopy, foliage density, leaves, photosynthetic ability
Frees up resources
Can infect the interior parts of the tree
branches/entire tree may rot and fall
Provides new available niches and habitats (positive)
Provides microhabitats for insects and other organisms
Insects can live in holes the dungi make in the tree bark
Provides a food source for insects and other organism
How are increases in prey and predator populations related? 
An increase in predator pop occurs slightly after increase in prey pop
An increase in predatory pop will cause a decrease in prey pop
Predator population is in response to the fluctuation of the prey population
What is a trophic cascade?
Trophic cascade: The negative effect the removal or decrease in a key species has on other trophic levels
Populations can experience exponential growth, death
Interruption of the flow of energy through the ecosystem/resource availability
What is niche partitioning?
Niche partitioning: decrease in comp over limited resources between 2 similar species because each species is accessing the resource in different ways
STOP the video at 13:10. Which stream types had a statistically lower macroscopic invertebrate species diversity than the seasonal streams? Intermittent streams
Explain how the Simpson’s Diversity Index is used to measure species diversity. Define each component of the equation.
It takes into account the species diversity and biodiversity based on random samples of a given environment
(# of each of the individual species/total)^2 and continue for each species and add up to get sum and subtract value from 1
Explain how species composition and species diversity affect the makeup of an ecological community
Species composition describes each type of species in a community so if there are more types or more organisms identifies, it says something about the species diversity or the variety
Discuss why two organisms that are in direct competition with one another cannot occupy the same niche.
Two organisms that are in direct competition with one another cannot occupy the same niche because eventually one organisms will outcompete the other because one will be better at accessing the resource therefore excluding and decreasing the other population
Explain how the relationship between the clownfish and anemone demonstrates that ecological interactions between organisms are often quite complex.
The clownfish and anemone demonstrate a mutualistic symbiotic relationship because the clownfish provides the anemone with nutrients while the anemone provides the clownfish with protection and shelter.
Create a graphic organizer that illustrates the differences between the various types of interspecies interactions. Describe how these interactions affect population densities of the species involved.
Species 1 | Species 2 | |
|---|---|---|
Predation | + | - |
Competition | - | - |
Parasitism | + | - |
Mutualism | + | + |
Commensalism | + | 0 |
The interactions can either keep the population of a certain species in a symbiotic relationship in check or harm/decrease the population density which decreases the overall species variety of biodiversity of an environment
Describe how a trophic cascade works and state an example.
When a keystone species is removed, it has a negative impact on other trophic levels as the populations are not in check and may either increase or decrease drastically; the wolves in yellowstone national park created this effect when the moose population grew exponentially without any predator which decreased its food source
Explain how niche partitioning works to decrease competition.
Niche partitioning is when 2 species access the resource in different ways such as temporal, spatial, morphological that creates less competition as they are not directly competing
Explain how a predator-prey interaction acts as an example of a negative feedback loop.
A negative feedback loop is regulating so when there is a decrease in the predator species, the prey will increase in size. But as this occurs, the increase in food will result in the increase in the predator population.
Describe how cooperation or coordination between organisms can result in enhanced movement of or access to matter and energy.
The increased coordination or cooperation will create an increase in the food supply or other limited resources that are fought after such as resource partitioning in which both organism face a win-win situation (such as temporal where species use the resource at different times, spatial where they use different habitats, morphological where there’s an evolution of different body shapes or sizes or more
AP Daily 8.6 Biodiversity
More diverse ecosystems are more adaptable to changes in the environment.
natural/artificial ecosystems with fewer component parts and with little diversity are less resilient to changes in the environment
Diversity of species in ecosystems may influence the organization of the ecosystem
Ecosystems can be stabilized with more diversity
Less vulnerable to drastic structural changes with env changes or when organisms are added/removed
Abiotic factors help maintain diversity*. Give two examples.*
Climate
Water and nutrient availability (with more water, more animals species and plants species can be supported)
Light availability (with more sunlight, more sunlights will grow)
Give two examples of how biotic factors help maintain diversity.
Producers help maintain ecosystem diversity
Consumers depend on producers for food/habitats
Reduce erosion
Dominant predators keep prey populations under control
Have diversified diets (don't put too much pressure on any one population
What is a keystone species? Give an example.
Keystone species: species the community structure depends on
Smaller populations compared to other populations in the community
When removed, the ecosystem often collapse
Often control the size of multiple predators
Overpopulation of prey species can deplete resources
Yellowstone national park- wolves
How is the African elephant a keystone species?
Tusks used to dig up riverbed= creates water holes for animals
Dung= provides habitats for insects and helps distribute seeds
Feeding behaviors influence landscape
Removal of trees/shrubs provide pathways for other animals
STOP the video at 8:08 Predict the change in ground flora of canopy trees if they were artificially planted immediately after the field was abandoned.
There would be less ground flora diversity as the canopy trees that are fully grown block sunlight needed for the population to grow and use for cellular processes
Explain how diversity influences the resilience of an ecosystem.
When an ecosystem has more variety and number of species, the more resilient it is to outside disturbances that are likely to wipe it out; if it did not have as much variety or number of species/organisms, it would not be able to repopulate after disturbances such as natural disasters, bottleneck effects, founder effect, etc.
Compare and contrast how abiotic and biotic factors contribute to the diversity of an ecosystem.
Both abiotic and biotic factors contribute to how resources are used in a resource and the carrying capacity of the species in an ecosystem. Plants or producers are often the base of the food webs of an organism and if they do not have certain abiotic factors such as sunlight in its range of tolerance, it will not be able to provide energy to organisms higher in the food chain.
In a marine ecosystem, the sea otter is a keystone species where it resides. The sea otter feeds on sea urchins, which in turn feed on kelp (seaweed). What would happen to the ecosystem if the sea otter were to be over hunted by orcas.
If the sea otters were over-hunted by orcas then there would be an increase in the food source, the kelp/seaweed which would overpopulate in the marine ecosystem, decreasing the amount of sunlight available for other producers to slowly destroy the food chain.
AP Daily 8.7 Disruptions to Ecosystems
Evolution is characterized by change in the egentic make-up in a population over time.
What is an adaptation? What causes adaptations to arise?
Adaptation: genetic variation that is favored by selection
A trait that provides an advantage to an organism in a particular environment
Can arise through mutations
List three possible results of increases in the frequency of adaptations.
Increases biodiversity
Populations evolve
Speciation can occur
What is an invasive species? Why do they often outcompete other native organisms?
Invasive species: is one that is not native to a specific area and harms the community it is introduced to
The introduction of an invasive species can be intentional/unintentional
Invasion species exploit new niches
Niche is free of predators or competitors
Outcompete other organism to resources
Population increases unchecked
Domesticated cats are an invasive species
They do not occur naturally in the wild
Feral cats are unsocialized cats and are invasive species in north america
First brought to US in the 17th c by european settlement
Kill billions of birds and small animals each year
Contribute to major reductions in bird populations
Have been suspected of causing extinction of many small animal species
Outcompete other predators
Human activity accelerated change on local and global levels.
Urbanization, deforestation, erosion, extinction, pollution, climate change
The introduction of new diseases can devastate native species
Human migration and overpopulation can accelerate spread of disease
What are some geological or meteorological events that can change ecosystems?
Large human disruptions
Chemical disruptions
Meteors, volcanoes
How do these events accelerate evolution?
By wiping out organism and leaves the ones left behind to occur the niches can cause changes in the impact
Reproduce isolation
Change in selective advantage
New niches
Changes