SCI Section 2 Flashcards
What is evolution and biodiversity?
genetic variation resulting in environmentally adaptive traits has resulted in a diverse number and types of species
What is community ecology?
how populations of species grow, disperse, and interact with other populations
What are ecosystems?
the integration of living and nonliving system components in specific geographic areas
What are biomes?
variation in global patterns of temperature, sunlight, and rainfall create geographic regions distinguished by different dominant forms of plants and animals
What are global energy and matter cycles?
global biogeochemical cycles on which all ecosystems depend on
What is the most common measure of biological diversity?
the number of different species in a certain area
What is Earth’s large number of species a result of?
a large amount of genetic diversity in species
What is genetic diversity?
the variety of genes
What are genes?
the chemical building blocks that provide the blueprint for how every individual organism grows
About how many different genes do all humans have combined? (referring to types of genes)
30,000
What is the exception to the fact that no 2 people will have the exact same combination of genes?
identical twins
What are species distinguished by at the most basic level?
how different their genes are
What is the ultimate source of biodiversity on Earth?
genetic diversity
The genetic differences between individuals in the same species can lead to what?
physical variety, such as in eye color, lead arrangement, or beak size
What are changes in the blueprint of a species over time?
evolution
Why do bears today have little resemblance to their ultimate ancestor?
evolution
What do you need to understand to learn how genetic diversity leads to species diversity?
the basic principles of genetic diversity
Where do all organisms inherit their genes from?
their parent(s)
Genes contain most/all of the instructions for which types of traits?
relatively simple traits
What do more complex traits require to produce?
the interaction of more than one gene
What is a phenotype?
the trait that is the result of a genotype
What is a genotype?
the genetic code for an organism
What is an organism’s genotype comprised of?
all of an organism’s genes
What are genes chemically made up of?
DNA
Genes are arranged within an organism’s cells on structures called ________________.
chromosomes
Genes have alternate forms that have different instructions for what the phenotype will be, the alternate forms are called _________.
alleles
If a gene in a population has 2 alleles, how many potential combinations are there for the genotype?
3
If an individual has 2 copies of a gene (B and b) what are the potential gene combinations?
BB, Bb, and bb
What is the dominant allele for Bb?
B is the dominant allele
What is the dominant allele for BB?
both are dominant
What is the dominant allele for bb?
there is no dominant allele
Is it possible to measure all the different alleles for a particular trait that occurs in a population?
No, it is impossible
What is Canis familliaris?
the domestic dog
Why do people breed certain breeds of the domestic dog?
to produce desired traits
What causes variations in size, shape, coat texture, color, and more in the domestic dog?
different combinations of alleles in different dog breeds
What is the only way a new allele can be produced?
through a mutation
What is a genetic mutation?
an error when genetic material is copied, and can permanently alter the genotype of an organism and its descendants
When do mutations occur?
randomly and spontaneously
When are mutations more likely to occur?
when an organism is exposed to anthropogenic chemicals, ex: those in tobacco smoke or radiation
Where does the mutation have to occur to be passed down to an organism’s offspring?
its reproductive cells
If there are many different alleles for a particular trait, will there be a small or large amount of genetic variation in the population?
a large amount
Do large or small populations usually have more genetic variation?
large populations usually have more
Why do larger populations have more genetic variation?
because there is a higher likelihood that the population has more alleles due to its size
In simple cases, what is a phenotype?
an expression of the genotype
In complex cases, what is a phenotype?
the result of the interaction between the genotype and its environment
What is the formula for phenotype? (complex)
Phenotype = Genotype + Environment
What 2 types of processes does species diversity result from?
adaptive and nonadaptive processes
How do most new species arise?
when the genotypes and phenotypes of two or more populations diverge through processes at the population level
How will a frog with longer legs compare with a frog with normal legs?
the frog with longer legs will be able to jump farther, allowing it to catch food more easily, thus increasing its fitness
What is fitness?
a measure of the relative viability and fertility of an organism
What is viability?
the ability to survive
What is fertility?
reproductive success
Harmful alleles tend to what?
die out with the individuals that carry them
Sickle–cell disease is an example of what?
harmful alleles
What is sickle–cell disease?
a disease that reduces the oxygen capacity of blood
What effects does sickle–cell disease have on humans?
it results in many severe mental and physical impairments, usually death
Sickle–cell disease occurs in people of __________ descent.
African
What is a benefit of sickle–cell disease?
it provides resistance to malaria
In Africa, there are many deadly diseases, but the most deadly disease is __________.
malaria
How many copies of the allele are necessary to produce sickle–cell disease?
2
What will happen if an organism has one allele for sickle–cell disease?
it will not develop the disease but will have some natural resistance against malaria
Who synthesized the concept of evolution through natural selection into a unifying theory?
Charles Darwin
Darwin made his observations about natural selection when aboard which ship?
the HMS Beagle
What was the name of Darwin’s natural selection theory when he published it?
“The Origin of Species by Means of Natural Selection”
When did Darwin publish his natural selection theory?
1859
What are the key ideas of Darwin’s theory of natural selection?
- Organisms produce more offspring than needed to replace parents
- Individuals will express a range of phenotypes
- Some phenotypes will allow an organism to be more fit than others in their environment
- The more fit individuals will have a better chance of reproducing, they will be selected and well–established
What does Darwin’s theory mainly explain?
why do individuals with certain traits survive and reproduce
What is an adaptation?
a trait that helps an organism become more fit for a particular environment
Will a species with more genetic variation adapt faster or slower than one with little genetic variation?
it will be able to adapt faster
What are the fastest ways to adapt to an environment?
changes in behavioral or physiological responses
Panting of a dog or a human sweating are adaptations that allow the organism to do what?
cool off
Plants dropping their leaves at the beginning of a dry season allows them to do what?
conserve water
When do short–term responses fail?
when an environment changes too much
As environments undergo major changes, what will happen to the species?
they will either die out or adapt through natural selection
Thick, fleshy leaves with thick, waxy surfaces allow a plant to do what?
conserve more water
The ability of a species to adapt to environmental changes depends on what?
how much and how fast that change occurs
Much of the current environmental change caused by humans is ____________ and _____________.
dramatic and sudden
What occurs when organisms from one population migrate to and mate with another population?
gene flow
In which species do high rates of gene flow occur?
species with much dispersal of individuals
Most populations are relatively ____________.
isolated
Genetic isolation in most species is an issue in what?
the maintenance of biodiversity
What type of adaptive process is genetic drift?
a nonadaptive process
What is genetic drift?
random changes in genotypes among small populations
The bottleneck effect is a type of __________ ________.
genetic drift
What is the bottleneck effect?
when a population is drastically decreased
What are the causes of the bottleneck effect?
hunting, habitat loss, a natural disaster, or changes in the environment
Increased disease and low fertility are problems linked with what?
low genetic variation
Why have cheetah populations decreased so much?
because of hunting and habitat loss
The cheetah population is so small, all cheetahs are basically what?
identical twins
Cheetahs tend to have _____ fertility and _____ rates of disease.
low, high
What percent of male cheetahs have abnormal sperm cells?
70%.
The only reliable studies have been conducted with which cheetahs?
zoo cheetahs
Do we know if cheetahs in the wild have reduced fitness?
No, because there haven’t been any reliable studies on them
How long can a significant change in a species genotype take?
hundreds to thousands of years
Smaller scale evolutionary changes can occur over a much ___________ time scale.
shorter
How many factors are important influences on the pace of evolution by natural selection?
3
What is the first factor that influences the pace of evolution by natural selection?
the rate of environmental change to which a species must adapt
What is the second factor that influences the pace of evolution by natural selection?
the genetic variation of a population, more genetic variation usually results in less time but the accumulation of mutations takes a lot longer
What is the third factor that influences the pace of evolution by natural selection?
adaptive traits can spread faster in small populations than in larger ones
Small populations are likely to undergo rapid evolution by which processes?
nonadaptive processes, such as genetic drift and bottlenecks
Do we know the actual number of species on Earth?
No
What does the total number of species in the world today equal?
the species that evolved over time minus the species that no longer exist
What happens when the environment changes so that a population is no longer adapted to it?
its growth rate becomes negative and will eventually reach zero
How can a population save itself when the environment changes?
it can either adapt or migrate to an environment it can succeed in
Is there always a favorable environment for a population?
No
Organisms that can’t adapt to environmental change will eventually go __________.
extinct
What is most of what we know about the evolution of life, based on?
fossils
What are fossils?
the remains of dead plants and animals that have been preserved in rock
What parts of an organism are usually fossilized?
typically the hard parts of an organism, and sometimes softer organic material
How can soft organic material get fossilized?
it is buried and protected by mud and sediment, over time it will harden
Where are the oldest fossils found?
at the deepest layers of Earth and the fossil record
What is the basis of the geologic time scale?
the fossil record
What does the geologic time scale divide time into?
various intervals from the formation of the Earth to the present
What characterizes the intervals in the geologic time scale?
distinctive events
When did bacteria appear in the fossil record?
3.5 billion years ago
When did multicellular and shelled organisms appear in the fossil record?
540 million years ago
From when can we trace identifiable species?
1–10 million years of the fossil record
When were mammalian species found in the fossil record?
1 million years ago
When were clams and marine species found in the fossil record?
10 million years ago
Do organisms found in the fossil records usually exist today?
No
What is the example given in the book for a species that was found in the fossil record and still exists today?
the ginkgo tree
Where is the ginkgo tree found?
in China and some parts of the US (in the US it is commonly used as an ornamental tree)
When did the ginkgo tree appear in the fossil record?
roughly 60 million years ago
How did the Dodo become extinct?
through overexploitation by European settlers and invasive species competing with them for food
Why were the Dodo hunted so much?
because they were large, flightless birds, basically an easy source of meat
What are Dodo birds?
large, flightless birds
When did European settlers start overhunting the Dodo bird?
during the 17th century or 1600s
Where was the Dodo bird hunted?
the Indian Ocean Island of Mauritius
What is habitat fragmentation?
the splitting up of habitats into smaller pieces
The construction of roads housing development, or shopping/industrial centers is an example of what?
habitat fragmentation caused by humans
Habitat fragmentation reduces the area of what?
contiguous habitat
What are the effects of reducing the area of contiguous habitat?
it creates barriers to the normal movement of a species
The mountain lion, wolf, and tiger all require what type of land?
large tracts of relatively uninhabited undisturbed land
Fragmentation creates more habitat that is along a(n) ________.
edge
What does increased edge habitat cause?
a change in the species composition of the habitat overall
Since there is more edge created, the inner portions of something like a forest are now closer to the outside, causing what?
causing organisms to penetrate into the forest more easily, resulting in them eating organisms that would have been safer without the edge
How does habitat fragmentation affect the size of the population?
it can divide the population into several smaller populations
How will the gene flow of the smaller populations caused by habitat fragmentation be affected?
it will be greatly reduced as the population will become genetically isolated and may lose genetic variation through genetic drift
What are exotic species?
organisms that are introduced by people to an area they are not native to
While moving things from place to place, what have humans brought to new continents and areas?
diseases and new species
The zebra mussel is an example of what?
an exotic species
Where is the zebra mussel native?
the Caspian Sea in Asia
Where did the zebra mussel first enter the US?
through the Great Lakes
How was the zebra mussel brought to the US?
through a ship
When was the zebra mussel brought to the US?
the 1980s
Does the zebra mussel have any known predators in North America?
no
How has the zebra mussel population grown in North America?
exponentially
Where in North America has the zebra mussel population grown?
the Eastern US and Canada
What has the zebra mussel done to its environment?
depleted food supplies, clogged water intake valves, and caused many other problems
When an exotic species enters a new area, what might it encounter?
an unexploited resource they can rapidly utilize
What happens to the populations of exotic species due to the fact that they have no natural predators in this new environment?
they grow rapidly and there is usually nothing to stop it
What do we need to know to fully explore the patterns of biodiversity?
how species distribution and abundance is limited by its environmental conditions
What is ecology?
the study of the relationship between organisms and their environment
What do relationships include in this context?
the adaptation of an individual’s physiology to environmental extremes, the killing and eating of prey, and the flow of carbon through an environment
To study such a diversity of natural phenomena, ecologists have divided the science into what?
a hierarchy from individuals to large–scale ecological systems
Different processes have what kind of effects on biodiversity?
different effects
What 3 things are critical to an organism’s survival in an environment?
its abiotic environmental conditions. the availability of resources, and a habitat for it to live in
What are conditions?
the chemical or physical factors in the environment that influence survival and growth
What do conditions determine?
which species and communities flourish in some habitats compared to others
For terrestrial systems, what determines the absence or presence of certain species?
the availability of light from solar radiation, temperature of air and soil, soil type, and amount of nutrients
Conditions for terrestrial systems vary depending on what?
location, or latitude and elevation
In aquatic systems, what determines the absence or presence of certain species?
temperature, available light from solar radiation, gradients in the amount of oxygen dissolved in the water, salinity, acidity
Conditions for aquatic systems vary depending on what?
depth of the water, the location in a stream, latitude, elevation, and more
What are the main locations in a stream?
upstream, midstream, and downstream
Under optimal environmental conditions, how will the species live?
they will thrive, or survive, grow, and reproduce
What happens as conditions become less optimal?
they will grow and survive, but might not reproduce
What happens when conditions become so bad they can barely live?
they will barely survive and will not reproduce but might grow
What is the range at which a species can exist?
its range of tolerance
Food, water, light, and oxygen are all examples of __________.
resources
What are resources?
aspects of the environment used to stay alive
The amount of available resources is important to which levels of ecology?
all levels of ecology
Can a habitat with a large amount of resources support a lot of species or just a few?
they can support a lot of species
What is the direct correlation between the amount of resources and the number of species?
suprisingly, there is very little correlation between the two
Where does the explanation of the little correlation between the amount of resources and the number of species lie?
the varied abilities of individual organisms to use resources under various abiotic environmental conditions
If a habitat has a large amount of resources but very extreme abiotic environmental conditions, will there be a lot of organisms that live there?
No, only the ones that are adapted to withstand these conditions can survive there
The large salt marshes that extend along the easter coast of the US from Georgia to Cape Cod are an example of what?
areas with a large amount of resources but very harsh environmental conditions
Salt marshes act like a ____________ _______ for large amounts of nutrients caught from the flow of rivers.
storage tanks
Do salt marshes produce high or low levels of biomass?
high levels
Is the vegetation within salt marshes diverse?
No
Is the vegetation within salt marshes abundant?
Yes
A few grass species make up what percent of salt marsh biomass?
over 95%
Why do only certain grasses dominate salt marshes?
because of only those species can process the nutrient–rich resources under the extreme environmental conditions
What causes the extreme environmental conditions in salt marshes?
fluctuation in salt concentrations throughout the year, low oxygen levels in the soil, and large amounts of toxins
How do salt concentrations increase in salt marshes?
through rapid evaporation
How do salt concentrations decrease in salt marshes?
through rapid flooding and heavy rains
What causes the low oxygen levels in the soil of salt marshes?
a high level of microbial decomposition that takes place, which uses lots of oxygen
What is another side effect of high microbial decomposition in salt marshes? (other than low oxygen)
it also produces large amounts of toxins
What adaptations allow salt marsh grasses to survive in salt marshes?
special tissues that allow them to concentrate and excrete water, air chambers in their roots, and the way they allocate their energy
How do air chambers in the roots of salt marsh grasses allow them to adapt to a salt marsh?
it allows them to create their own oxygen–rich microhabitats in the soil surrounding them
Populations in different species interact with each other in which 3 ways?
interspecific competition, predation, and mutualism
What is interspecific competition?
different species competing for a limiting resources in the same location
What is a limiting resource?
a resource that the population needs but is low and decreasing
What happens to the population that depends on the limiting resource when it decreases?
it goes down as well
If the resource limits the growth and reproduction of a resource, can it be shared?
No
If a resource cannot be shared, what happens to the species that can’t receive it?
it will go extinct
What is competitive exclusion?
a principle that states when a limiting resource can’t be shared, one species will succeed and the other will go extinct
Does competition for resources occur with plants?
yes
What is Avena fatua?
the wild oat
Where is the wild oat most abundant?
the Great Plains of North America
What type of plants does the wild oat compete with for resources?
agricultural crops, such as wheat, barley, and flax
Why do wild oats outcompete crop plants?
because their seeds ripen earlier, allowing them to start growing before the other species
What allows the crop plants to survive against the wild oats?
human intervention
Niche is closely related to which principle?
the competitive exclusion principle
What word is niche confused with?
habitat
What is niche?
The role of an organism within a community, what it does and how it lives
What phrase do many ecologists rephrase the competitive exclusion principle as?
two populations that fill the same niche, such as by feeding on the same limited resource, cannot coexist
What is the exception to the competitive exclusion principle?
if they 2 populations partition the resources so that their niches don’t overlap completely, they can coexist
What is predation?
the use of one species as a resource by another
This definition of predation allows us to include which other species interactions?
herbivory and parasitism
What is herbivory?
where animals eat plants, seeds, or fruits
What is parasitism?
where animals, plants, fungi, or bacteria feed on another organism or use it as a habitat
Does parasitism cause death?
Most of the time it doesn’t, it just causes injury
What establishes how energy flows in an ecosystem?
predation
How do predators limit the population of prey?
by eating them and changing their behavior
How do most predator–prey cycles in laboratory systems end?
by the prey population going extinct, and the predator population going extinct soon after
What is the third major type of population interaction?
mutualism
Do mutualistic interactions increase or decrease the survival probability or reproduction of the species?
increase
Mutualism isn’t species helping each other cooperatively, but __________ ____________.
reciprocal exploitation
What happens with mutualism when a population’s self–benefit becomes too low?
they will most likely stop the interaction as it will no longer be of value
What is the most common type of mutualism?
the interaction between plants and animals
What is the most important type of mutualistic interaction?
the interaction between plants and their pollinators
Is the mutualistic interaction weak or strong when pollinators pollinate many different plants and many plant species are pollinated by different pollinators?
it is weak
What do many plant species depend on pollinators for?
their reproduction and survival
Mutualistic interaction is strong with what type of mutualism?
symbiotic mutualism
What mutualism type occurs when one animal species pollinates only one plant species, and vice versa?
symbiotic mutualism, or strong mutualistic interaction
What is symbiotic mutualism most likely a result of?
resource partitioning in the evolutionary past
Where do most of the important ecological processes occur?
at a level higher than the population level, the ecological community
What is a community?
any assemblage of populations in a particular area or habitat
What is a food web?
a summary of the species that make up a community, and how they are linked by energy flow
How do food webs compare to food chains?
food webs are more complex
What are usually the producers in an aquatic food web?
algae and phytoplankton
Is phytoplankton single–celled or multicellular?
single–celled (unicellular)
Are zooplankton unicellular or multicellular?
unicellular
Are algae unicellular or multicellular?
multicellular most of the time
In most aquatic systems, what usually consumes phytoplankton?
zooplankton and other carnivorous, microscopic animals
In most aquatic systems, what usually consumes algae?
herbivorous fish
In most aquatic systems, what usually consumes zooplankton?
carnivorous fish
In most aquatic systems, what usually consumes insects?
carnivorous fish
In most aquatic systems, what usually consumes herbivorous fish?
carnivorous fish
In most aquatic systems, what usually consumes carnivorous fish?
the secondary consumers, including tarpons and several bird species
Tarpons are usually the __________ fish species in an aquatic system.
largest
What are the levels in a food chain/web called?
trophic levels
The word trophic” comes from which Greek word?”
trophe”
Trophe is Greek for _______________.
nourishment
What is the lowest trophic level?
the primary producers
Plants and algae are at which trophic level?
the lowest trophic level, the primary producers
Do primary producers rely on other organisms for energy?
No
How do primary producers receive their energy?
through the food they make through photosynthesis
What does photosynthesis require?
CO2 (carbon dioxide), sunlight and water
Do consumers rely on other organisms for food?
Yes
All the organisms with a higher trophic level than the primary producers are ______________.
consumers
Grasshoppers, caterpillars, and termites are usually examples of which trophic level?
primary consumers
Which trophic level do primary consumers feed directly on?
primary producers
Robins and frogs are usually examples of organisms in which trophic level?
secondary consumers
What trophic level do secondary consumers feed on?
primary consumers
What is the trophic level after secondary consumer?
tertiary consumers
Tertiary consumers feed on organisms from which trophic level?
secondary consumers
What is the trophic level after tertiary consumers?
quaternary consumers
Quaternary consumers feed on organisms from which trophic level?
tertiary consumers
What is used to show the energy transfer between trophic levels?
ecological pyramids
What percent of energy is transferred from the Sun to the primary producer?
1%.
What percent of energy is transferred from one trophic level to the next?
10%.
Why does only 10% of energy get passed on from one trophic level to the next?
because the rest is lost as heat
Why is the biomass for trophic levels get lower as you go up the ecological pyramid?
because of the lack of energy that is transferred
As you go up the ecological pyramid what decreases?
amount of available energy and biomass
Are keystone species the most abundant species in a food web?
No
What is a keystone species?
a species that plays a vital role in the community that is more important than its relative abundance would suggest because of its position in the food web
Why was the keystone species concept developed?
to explain the effect of removing a relatively rare species from the food web
What are the 3 types of keystone species?
predators, ecosystem engineers, and mutualists
How are predators a keystone species?
through their controlling of their prey
What population do sea otters keep in check?
the sea urchin population
What would happen if the sea otter wasn’t in a community?
the sea urchins would overpopulate the sea floor and would consume kelp forests, which provide shelter and food for marine organisms
How are ecosystem engineers a keystone species?
they create and maintain habitats for other species
How is the North American beaver an ecosystem engineer?
they transform streams into ponds when they build their dams, creating a habitat for pond plants and animals
How are mutualists keystone species?
they interact with other species for each other’s benefit, kind of like mutualism
Mycorrhizal fungi are an example of which type of keystone species?
mutualists
The mycorrhizal fungi on and in tree roots help trees do what?
extract nutrients from the soil and help them grow
What are the 3 most important aspects of an ecosystem?
- its boundary
- its biotic component
- its abiotic component
What is an ecosystem boundary?
Where an ecosystem starts and ends
What is the biotic component of an ecosystem?
the living things in an ecosystem
What is the abiotic component of an ecosystem?
the physical and chemical parts that are nonliving, including temperature, water, salinity, soil structure, and nutrients
What is salinity?
the dissolved salt content of water
The ecosystem is which level in the hierarchy of biodiversity?
the first level
An ecosystem is not just the components within it and the boundary, what else is it?
the processes occurring within it
What is usually the boundary in most aquatic ecosystems, such as lakes, ponds, and streams?
the boundary between the land and water
In most cases, determining the boundary of an ecosystem is ____________.
difficult
How do environmental scientists estimate the boundary of terrestrial ecosystems?
by the range of the populations that make up the biological community or by ecological processes
National parks and reserves are examples of ecosystem boundaries not set by scientific criteria but by what?
administrative criteria
Knowing the boundary of an ecosystem makes it easier to what?
identify the biotic and abiotic components that make up a system
What influences how energy flows in an ecosystem?
the types of species within it
How do energy pyramids from one ecosystem compare to others?
they stay relatively constant
How do biomass pyramids from one ecosystem compare to others?
they vary from ecosystem to ecosystem
What does the variation of biomass pyramids depend on?
the characteristics of the populations making up the trophic levels and the physical and chemical structure of the ecosystem itself
All ecosystem–level processes are subject to what?
change
What is a disturbance?
a change in an ecosystem, where physical, chemical, and some biological agents cause rapid injury or death of organisms, leading to damage or collapse of the biotic component
Hurricanes, ice storms, and natural forest fires are examples of which type of disturbance?
natural disturbances
Clearcutting of forests, agriculture, and air pollution are examples of which type of disturbance?
anthropogenic disturbances
What are natural disturbances?
disturbances that occur naturally and have no human involvement
What are anthropogenic disturbances?
disturbances caused by human activities
What is the slow invasion of a lake by an introduced species called?
a perturbation
What is a perturbation?
a broader version of a disturbance, it refers to any kind of change to the equilibrium in an ecosystem
What is an equilibrium in an ecosystem?
The balance in an ecosystem
The gradual increase in Earth’s temperature by 1 degree Celsius is an example of a(n) _____________.
perturbation
The rapid increase in Earth’s temperature by 2 degrees Celsius is an example of a(n) _____________.
disturbance, specifically an anthropogenic disturbance
What is resilience in an ecosystem?
the rate at which an ecosystem returns to its original state after a disturbance
How fast would a highly resilient ecosystem return to its original state?
very fast
How fast would a less resilient ecosystem return to its original state?
slowly
How fast would a highly resilient ecosystem recover from a drought that eliminated half the species?
the species would return the following year
How fast would a less resilient ecosystem recover from a drought that eliminated half the species?
it would take many years, maybe not ever
What are biomes?
regions with differing vegetation and wildlife
How many major terrestrial biomes are there?
10
What biome is the Amazon in?
the tropical rainforest
What is the warmest and wettest biome?
the tropical rainforest
In the tropical rainforest biome, is ecosystem productivity high or low?
high
How is diversity in the tropical rainforest biome?
plant and animal diversity is very high
Where is much of the energy and nutrients found in the tropical rainforest biome?
the vegetation
In the tropical rainforest biome, are soils rich or poor in mineral nutrients?
extremely poor
Is the tropical dry forest seasonal or year–round?
seasonal
What type of tree is common in the tropical dry forest biome?
deciduous trees
What do deciduous trees do with their leaves and flowers during the dry season?
they drop them
How do productivity and diversity in the tropical dry forest biome compare with the tropical rainforest biome?
plant and animal diversity and productivity are much lower in the tropical dry forest biome
The US Pacific Northwest is part of which biome?
the temperate rainforest biome
What tree is common in the temperate rainforest biome?
tall coniferous trees
How are winters in the temperate rainforest biome?
mild
How is rain in the temperate rainforest biome?
rain is frequent and heavy
How often does fog occur in the temperate rainforest biome?
very frequently
How tall are most trees in the temperate rainforest biome?
60–70 meters high
What factors in the temperate rainforest biome create optimal conditions for tall trees?
mild winters, heavy rain, and frequent fog
How does productivity in the temperate rainforest biome compare with the tropical rainforest biome?
productivity is about half of the tropical rainforest biome
Soils in the temperate rainforest biome tend to be rich in what?
organic matter
Where is the temperate broadleaf forest biome found?
the eastern US, southern Canada, Europe, and eastern Asia
What is the primary tree type in the temperate broadleaf forest biome?
deciduous trees
How are rainfall levels in the temperate broadleaf forest biome?
they are moderate
How is seasonal temperature variation in the temperate broadleaf forest biome?
there is a high seasonal temperature variation
How does the temperate broadleaf forest biome productivity compare to temperate forests?
they are similar
What causes the rich soil in the temperate broadleaf forest biome?
when plants and trees shed their leaves, the leaf litter decomposes into rich soil
How does the diversity in the temperate broadleaf forest biome compare to the tropics?
plant and animal diversity are much lower than in the tropics
What is the dominant plant species in the boreal coniferous forest biome?
conifers
What are the most common types of conifers in the boreal coniferous forest biome?
spruces and firs
How tall do the conifers usually get in the boreal coniferous forest biome?
10–20 meters high
What types of mammal species are common in the boreal coniferous forest biome?
large mammal species, such as moose, bears, wolves, and the Siberian tiger
How does productivity in the boreal coniferous forest biome compare to the tropical rainforest biome?
productivity is 1/3 of tropical rainforests
Is plant diversity high or low in the boreal coniferous forest biome?
plant diversity is low
In the boreal coniferous forest biome, yearly weather variation results in what?
dramatic variation in seed production
What does dramatic variation in seed production result in?
dramatic fluctuation in bird and other animal populations
What causes the poor soils and low leaf litter decomposition in the boreal coniferous forest biome?
low temperatures and chemicals in foliage
When do temperate grasslands occur?
when precipitation reaches a point so low that there is not enough water to support dense forests and the vegetation shifts to grasslands
What are grasslands called in the US?
prairies
What are grasslands called in Central Asia?
steppes
How does productivity in the temperature grassland biome compare to tropical rainforests?
productivity is about 1/3
What causes the accumulation of organic matter, resulting in the temperature grassland biome?
decomposition of dead vegetation is limited by low precipitation rates
What does the accumulation of organic matter in the temperature grassland biome result in?
rich agricultural land
Where is the savanna most common?
in dry tropical regions of Africa
How is the tropical scrub forest different from the savanna?
they occur at different times of the year and the tropical scrub forest does not have the same biomass level as the savanna
What is the rainfall range for the tropical scrub forest and savanna biome?
10–150 cm/year
About how much rainfall do the driest 3–4 months of the year in the tropical scrub forest and savanna biome get?
less than 5 cm/month
What vegetation is most common in the tropical scrub forest and savanna biome?
scrub vegetation
Why is scrub vegetation small and stunted?
because of the limited nutrients and short growing season
What do migrating herds of herbivores follow in the tropical scrub forest and savanna biome?
the rain and move across the biome
What is a wildebeest classified as? (carnivore, herbivore, or omnivore)
they are herbivores
What is responsible for generating and maintaining the savanna biome?
fires and grazing
How do productivity and diversity in the tropical scrub forest and savanna biome compare with tropical rainforests?
they are both significantly less than a tropical rainforest
Where is the Mediterranean biome found?
in countries bordering the Mediterranean Sea and California
What is the Mediterranean biome known as in California?
chaparral
When does the Mediterranean biome receive most of its rainfall?
during the winter
Is the Mediterranean biome dry or wet?
it is dry and receives most of its rain in the winter
What is vegetation mostly comprised of in the Mediterranean biome?
dense, woody shrubs and small trees
What qualities do the leaves have in the Mediterranean biome?
they tend to be small, leathery, and waxy to help them retain water
What adaptation has most vegetation in the Mediterranean biome evolved to help combat the frequent fires?
fire–resistant bark
Jackrabbits, kangaroo rats, chipmunks, mule deer, and many species of lizards are all commonly found in which biome?
the Mediterranean biome
What animal types mainly make up the Mediterranean biome?
several bird species, small mammals, mule deer, and several species of lizards
What is a desert?
Any area that receives less than 25 cm of precipitation per year
What biome are Mongolia and Montana considered to be?
the desert biome, though they are cold deserts
Where is the largest desert found?
Antarctica
What soil types does the desert biome usually have?
sandy or rocky soil
What vegetation is common in the desert biome?
sparsely spaced shrubs and grasses are common
Productivity in the desert biome is what percent of productivity in tropical rainforests?
0% to 5%
Many species in the desert biome have developed adaptations to combat what?
the lack of water
Where is the tundra biome?
the region beyond the tree line
What is the tree line?
the upper limit of tree growth at high latitude or elevation
What vegetation is common in the tundra biome?
grasses, grass–like sedges, lichens, and dwarf trees
Does the soil in the tundra biome melt completely?
No, it stays frozen year–round
What is the soil in the tundra biome called?
permafrost
How much does the soil in the tundra biome thaw during the summer?
1/2–1 meter
Productivity in the tundra biome is what percent of productivity in tropical rainforests?
5%–10%
What is the most common mammal species in the tundra biome?
rodents, such as lemmings
Rodent populations in the tundra biome fluctuate depending on what?
the amount of resources available
Bird populations in the tundra biome may be abundant in the summer, but what do they do during the winter?
migrate south
Why aren’t aquatic regions divided into biomes?
because they lack a large variety of plants used to divide terrestrial biomes
What are the 2 major types of aquatic systems?
freshwater and marine
Are saltwater concentrations in freshwater systems high or low?
salt concentrations are low
What 2 groups freshwater systems be divided into?
flowing rivers and standing waters
Rivers and streams are examples of which type of freshwater system?
flowing rivers
Ponds and lakes are examples of which type of freshwater system?
standing waters
What are plants and animals that live near the bottom of aquatic systems known as?
the benthic community
What other type of community do lakes and ponds have?
an open–water community
What organism dominates open–water communities?
phytoplankton (single–celled algae)
What are lake and pond ecosystems influenced by?
thermoclines
What are thermoclines?
abrupt changes in the temperature of the water with depth that prevents the mixing of layers of water
What percent of Earth is covered by ocean?
roughly 71%
The ocean is larger than which biomes?
all the biomes combined
At which depth is there not enough light for photosynthesis in oceans?
100–200 meters
How do most deep–water organisms get their food?
they either wait for it to descend to them or migrate toward the surface
The lack of nutrients in the water in marine ecosystems is what?
a major limiting factor, leading to low species diversity and abundance near the surface
In marine ecosystems, where does peak species diversity usually occur?
at depths of around 2,000–3,000 meters
Where are most of the world’s fisheries found? (in which waters?)
in waters near the surface and mixed with nutrients
Nutrient–rich water in fisheries allows for what?
high levels of productivity and vast species abundance and diversity
Are wetlands terrestrial or aquatic?
they are transitional areas between both
Salt marshes, bogs, swamps, and intertidal areas are examples of what?
wetlands
What are the 3 major types of wetlands?
marine (the intertidal region), estuarine, and freshwater
Freshwater wetlands make up what percent of all wetlands in the US?
91%.
What are estuarine wetlands?
where salt and fresh water mix at the mouths of rivers
Bogs, marshes, swamps, and peatlands are examples of which type of wetland?
freshwater wetlands
How are freshwater wetlands different than open waters?
freshwater wetlands have water at or near the soil surface for most of the year
Are salt marshes highly or less productive?
highly productive as they are important nesting and feeding sites for many animals and birds
Elements are constantly _________ within the biosphere?
cycled
What happens between the biosphere, soils, and water?
animals and plants grow, die, and decompose
What are the cycles that occur between biosphere, soils, and water known as?
biogeochemical cycles
Biogeochemical cycles have been altered by what?
human activities that release excess amount of an element into the atmosphere, soil, or water
What is the biosphere?
the sum of all the ecosystems on Earth
Changes in biogeochemical cycles have effects on what?
ecosystems, landscapes, and the global system
For example, the release of nitrogen and phosphorous from fertilizers can result in what?
the over–fertilization of natural ecosystems
What is the main agent responsible for dissolving and transporting necessary chemical elements?
water
What do we need to know before we can understand how individual elements cycle?
the framework of the water cycle
What is the driver of biogeochemical cycling on Earth?
the water cycle
Water in the atmosphere falls on Earth as what?
precipitation, usually rain or snow
How does water return to the atmosphere after being taken up by plant roots?
through transpiration
What is transpiration?
the loss of water from the stomates in leaves during photosynthesis
What are stomates in leaves?
the openings in the leaves
What is the combination of evaporation and transpiration called?
evapotranspiration
Where does water eventually end up when it penetrates the soil?
the groundwater system
What is the groundwater system?
the water that fills the species in rocks and sediments below the soil
What is runoff?
rainfall draining from the land into water bodies or sinking into the soil
Where do all streams and groundwater eventually reach?
the ocean
The ocean is the ultimate ____________ of water on Earth.
reservoir
What is the main energy source for the water cycle?
solar energy
Why is solar energy the main energy source for the water cycle?
because evaporation from the oceans is crucial to the water cycle, and the energy that causes this is energy from the Sun or solar energy
How many processes run the carbon cycle?
4
What are the processes that run the carbon cycle?
photosynthesis, respiration, decomposition, and combustion
How is photosynthesis one of the processes that run the carbon cycle?
when plants go through photosynthesis, they remove carbon dioxide and incorporate it into plant material, such as leaves, roots, and shoots
What is carbon fixation?
plants incorporating carbon into plant material
When is plant carbon returned to the atmosphere?
when plants respire at night
When organisms die, the carbon that was part of their biomass decomposes, resulting in what?
carbon and its other elements continuing the cycle
What happens to a small fraction of organic matter in the biosphere that gets buried in sediment before it can decompose?
it can be fossilized and may eventually turn into coal, oil, and natural gas
The compounds coal, oil, and natural gas are collectively referred to as fossil fuels due to what?
the fact that they are fossils and they contain carbon, which can be burned as CO2
What does combustion, such as forest fires or the burning of fossil fuels, do involving the carbon cycle?
they release carbon back into the environment
Where is the greatest amount of carbon on Earth tied up in?
carbonated rock, like limestone and organic matter, in sedimentary rocks
Does the abiotic pool of carbon stored in carbonate rocks cycle quickly?
No, they do not cycle very quickly
What type of rock is shale?
sedimentary rock
Oceans hold a large amount of _________. (answer is an element)
carbon
Is the carbon annual net gain in oceans large or small?
the net gain is very little
The chemistry of oceans is changing, they are becoming more acidic due to what?
higher levels of CO2 in the atmosphere
What is the most important path in the carbon cycle?
the movement of carbon between the atmospheric and biospheric pools because it cycles rapidly
Without human disturbance, is the carbon exchange between land plants and soils in equilibrium with the atmosphere or not?
Yes, there is no net flux of carbon between the pools
Without human activity, what state is the global carbon cycle in?
steady state
What is the largest and most significant human alteration of the carbon cycle?
the burning of fossil fuels
What is slash–and–burn agriculture?
when people cut down trees and vegetation for agriculture and space and the vegetation is then burned
In addition to destroying a large amount of biodiversity, what else does the destruction of forests add to the atmosphere?
significant amounts of carbon
What is nitrate susceptible to?
leaching
What is leaching in the context of elements?
where an element is washed out of the soil by moving water
If a site is disturbed, perhaps by human activities, what may happen to the nitrate in the soil?
it may leach substantially and can have a significant impact on rivers and streams
A high accumulation of nitrate in wet soils can lead to what?
denitrification
What is denitrification?
the natural conversion of nitrate into gas nitrous oxide or N2O
What is N2O?
nitrous oxide
What type of gas is N2O?
N2O is a greenhouse gas
Which element is often the limiting element in terrestrial systems?
nitrogen
What is the nitrogen cycle important in?
the regulation of net primary productivity and plant growth
The nitrogen cycle is a complex cycle with significant effects on which 2 things?
pollution and productivity
What is N2O commonly referred to as?
laughing gas
