Ecology Introduction Student Guided Notes What is Ecology? Ecology is __________________________________________________________ _____________________________________________________________________________. In other words, ecology has to do with the _________________________________________ and with how the __________________________ _________________________________________ _________ parts of an environment fit together and how one affects the other. Ecologists often study _______________________ ________________________________________. An ecosystem is ____________________________ ____________________________________________ ____________________________________________ ___________________________________________.

Ecosystems can cover large areas, such as the brush grasslands of the Cental Okanagan Valley or the coastal Douglas Fir ecosystems on Vancouver Island. Ecosystems can also be small, such as a single tidepool or a rotting log. Ecosystems are made up of ______________________________________________________ _______________________________. The biotic and abiotic components of an ecosystem are closely tied. __________________________________________________________________ __________________________________________________________________ _______________________________________________________. Different kinds of organisms play different roles in the environment. Plants make usable energy from sunlight and basic nutrients, animals consume the plants, other animals may consume those animals, and if any of these organisms die, bacteria and fungi are largely responsible for breaking down and using the nutrients that were once used by the organism and returning them to the earth. These nutrients can then again be used by the plants. ____________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________

__________________________________________________________________ When studying ecosystems we must look at all of the interactions of all of the components of that ecosystem. Ecologists seek to explain: life _______________________________________________ _________________________________________________ of organisms the movement of materials and energy through living communities the

______________________________________________________________, and the __________________________________________________________ in

context of the environment. Levels of Organization Where does the ecosystem fit within the various levels of organization? The Biosphere The biosphere is the _________________________________________________ of organization. The biosphere is a thin layer around the earth that includes ______ _______________________________________________________. This thin layer includes the ___________________________________________________ ________________________________________________________. Most organisms live within the first few meters of the surface of land and oceans. The biosphere has been divided into distinct regions based on the dominant forms of plant life and prevailing climate. These regions are referred to as Earth's biomes. The Ecosystem There are many ecosystems within each biome. Ecosystems include the ____________________ ____________________ in a particular place. Example: A pond.

The pond contains a variety _____________________________________________ ____________________________________________________________ These

organisms interact in ways that affect their survival. They are all a part of the pond food web. __________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ __________________________________________________________________ Communities Communities are defined as ____________________ __________________________________________ __________________________________________ Populations __________________________________________ __________________________________________ __________________________________________ Organism This is the simplest level of ecological organization. Organism refers only to the ______________________ __________________________________________ _____________________________. Research at this level involves things like adaptations. This is what the levels of organization look like: Note the location of the ecosystem in this hierarchy.

Niche Although not part of the level of organization _______________________________ _____________________________________________ is extremely important and _________________________________________________________________. A way of life. The organisms JOB in its habitat!

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________) all contribute to its niche. Here are a few important definitions. ___________________________________: The range of conditions a species can potentially tolerate and the range of resources it can potentially use. ___________________________________: The range of resources the species actually uses. Any differences between the fundamental and realized niches are due to ______________________________________________. __________________________________: tend to have broad niches as they can tolerate a wide range of conditions and use a variety of resources. __________________________________: have a narrower niche as they tend to operate in more specific conditions and use specific resources. Human Impact Human presence has _________________________________________________. Humans change existing ecosystems. The human increase in population threatens the stability and diversity of the planet. It is ironic that this instability threatens the human population itself. For

example, the destruction of the rain forest may lead to an increase in carbon dioxide which raises the world temperature. ______________________________________ __________________________________________________________________. Many of these organisms are needed for humans to survive. It is estimated that there are over _______________________________________ ____________________________________. Only 2 million have been identified. _______________________________________________________________________________________________________________, developing and over harvesting natural resources. Extinction occurs naturally but ___________________ _____________________________________________. The extinction of species reduces valuable resources available to humans.

Flow of Energy in Ecosystems

Food Chain vs Food Web There are many relationships within a given ecosystem. Perhaps the most obvious type of relationship is a ____________________________________. We can use _________________________________________________________________ __________________________________________. A food chain is a _________ __________________________________________________________________. Food chains simply describe _____________________________. They _________ ____________________________________________________ in an ecosystem, ______________________________________________________________. They are useful for looking at simple relationships between specific members of an ecosystem. In reality, _________________________________________________________ ________________________________________. This network is ____________ ______________________. Food webs more clearly ________________________ _____________________________________________________. The more organisms that are included, the more complex the food web becomes. You should note that the arrows in a food chain or web _______________________ ______________________________________________________. In other words, you could replace the arrow with the words “________________________.” Feeding relationships are only a small portion of the many types of relationships that exist in ecosystems. The components of ecosystems interact with each other in many complex ways. ______________________________________________________ __________________________________________. Some organisms work together to achieve common goals. Climatic variations, natural disasters, and human activities all affect the organisms in an ecosystem.

__________________________________________________________________ _________________________________________________________________________________________________________________________. This energy originates from the sun.

Organism Trophic Type Prey/Food Predators/Grazers algae primary producer --- krill, fish, blue

whales birds carnivorous

consumer krill, fish seals, killer whales

blue whales planktivorous consumer

algae, krill killer whales

fish omnivorous consumer

algae, krill birds, seals, killer whales

killer whales top consumer blue whales, fish, birds, seals

---

krill herbivorous consumer

algae fish, blue whales, birds

seals carnivorous consumer

fish, birds killer whales

Flow of Energy _________________ is the ultimate source of energy for all living things. How does energy flow through an ecosystem? Producers are __________________________ ______________________________________ ______________________________________ ______________________________________. These organisms are_______________________ because they make their own food. Examples of autotrophs are plants, photosynthetic bacteria, and algae.

Consumers are _________________ _____________________________ _____________________________ _____________________________. These organisms that eat other things are called __________________. Following is an explanation of the various levels of consumers.

Primary consumers, called __________________________ _________________________________. A cow eating grass would be an example. Secondary consumers can be ______________ ______________________________________ ______________________________________. A bear would be a good example for the omnivore as they can eat various berries or fish. Tertiary consumers at the top of the food chain _________________________________. A cougar is only one example of a tertiary consumer. Decomposers _____________________________________ ______________________________________ _________________________________ are examples of decomposers. It is estimated that each acre of soil

Energy Pyramids Energy Flow The idea of a food web is fairly simple. Most students are familiar with the idea that plants produce energy from the sun by photosynthesis, animals eat plants, other animals eat those animals, and the dead organisms are decomposed by detritus (bacteria and fungi). The different viewpoint here is that ______________________ ______________________________________________ in the food web. In a food web the direction of the ____________________________________________ __________________________________________. Because ____________________ _________________________________________ (the transfer is not 100% efficient) __________________________________________________________ _________________________________________________________________. This is the concept of a _______________________________. Each level of the pyramid is referred to as a _______________________ and ____ _______________________________ _______________________________ _______________________________ ___. There is generally a __________________ of the food chain This energy loss can be depicted using an _______________________________. Notice the pyramid is ______________ _______________________________ ________________________________ _______________________________. The mass (weight) and numbers of organisms ______________________________ _______________________________________. In an Ocean Energy Pyramid it takes about 1000 kilograms of phytoplankton to support 0.2 kilograms of tuna (1 can). The Role of Photosynthesis and Respiration If the sum is the unltimate source of energy for all organisms then how is that energy captured? The suns energy is captured by producers in a process called photosynthesis. Photosynthesis is the _____________________________________ _____________________________________________________________________________________________________________________________________. In plants, this process occurs in specialized cell organelles called _____________. Photosynthesis is the process that ________________________________________ ___________________________________________ that is the base of the energy pyramid.

The chemical reaction that takes place in chloroplasts (say inside a tree leaf) uses the light energy from the sun to convert __________________________ _________________________________________________________________ ____________________________________. Cellular respiration is the ______________________________________________ ________________________________________________________________________________________ (adenosine triphosphate) that can do work inside cells. This process occurs in specialized cell organelles called _______________________. The chemical reaction that takes place in mitochondria (say inside a muscle cell) uses _______________________________________________________________________________________________________________ the energy currency of cells. It is important to note that ____________________________________________ ___________________________________________________________________________________________________________________________________. As well as being transferred as an energy source, carbon transfers between organisms through photosynthesis and respiration. ___________________________________ __________________________________________________________________ __________________________________________________________________. When an organism dies and is broken down this carbon is again released in its simple form of carbon dioxide. Respiration also gives off carbon dioxide. The carbon cycle is of environmental concern because the destruction of forests and the burning of fossil fuels is increasing the amount of carbon in the atmosphere________________________________________________________________________________________________________________________________________________________________________________________________ _____________________

Bioaccumulation and Biomagnification Bioaccumulation _____________________________________________ _____________________________________________, such as petroleum-based pesticides, and other toxins, ___ __________________________. When a consumer eats these toxins, ___________________________________ _____________________________________________ Bioaccumulation then is the increase in concentration of a substance in living organisms as they take in contaminated air, water, or food. Bioaccumulation is a problem in the north because of higher concentrations of toxic pollution. Also, northern animals have a lot of fat to keep them warm, toxins accumulate mostly in fat.

Biomagnification When such a _____________________________ _______________________________________ _______________________________________, depositing in the fatty tissues. The higher the trophic level the greater the risk of fat-soluble toxin acquisition and concentration in the tissues.

Symbiosis What is Symbiosis? The word symbiosis comes from the Greek roots "sym" meaning ________ and "biosis"

meaning_________________. Symbiosis describes situations in which animals live with each other. Whenever two organisms of different species ______________________________ _______________________, often but not always to the benefit of both organisms, that's symbiosis. Symbiosis can occur between _____________________________ ________________________________________________________. Some symbiotes are so closely intertwined that it's difficult to tell where one organism ends and the other begins. And in the case of plant/animal symbiotes, it can be difficult to tell whether the organisms are plants, animals, or a little bit of both.

There are three main types of symbiosis; __________________________________ ____________________________ Parasitism In parasitism the ____________________________________________________. Parasitism does not often result in immediate death of the host organism. There are two types of parasites. Ectoparasites: ___________________– ticks, fleas, leeches. Endoparasites: __________________ – bacteria, protists, worms.

Commensalism In biology, commensalism is a relation between individuals of two species in which one species obtains either nutrients, shelter, support, or locomotion from the ______ species, which ____________________________________________. The commensal relation is often between a larger host and a smaller commensal; the host organism is unmodified, whereas the commensal species may show great structural adaptations.

A commensal relation based on shelter is seen in ____________________________

____________________________________________, where they are protected from predators. In another example ____________________ often follow cattle and _________________________________________________________________________________________________ from the cow without injuring the cow. However, _________________________________________________________ from the egret. Mutualism Mutualisms are ecological interactions between two species ____________________________ ____________________________________ _____________________________. A species may be so dependent that it cannot _________ _________________________________. In other cases, a species can interact mutualistically with more than one partner or even live without its partner(s) under certain conditions. Although _____________________________________ _____________________________________ ______________________, we still expect each species to be "selfish" and to evolve traits that provide the maximum possible fitness benefit while minimizing cost. An example of mutualism takes place between Ants and Bull’s horn. Ants get food from the shrub and in return protects the shrub from herbivores. ___________________________________________________________________________________________________________________________________. The pollinators obtain nutrients from the flowering plants and in turn, carry the pollen from one plant to another for plant fertilization. Flowers lure pollinators with __________________________________________________.

Properties of Populations

What is a population? A population is ______________________________________________________ _______________________________________________________. A population can be defined by any boundary. For example we could talk about the population of humans at your school, the population of your city, the population of your province etc. When scientists study populations they focus on the population as a whole, and look at characteristics such as _____________________________________________

________________________________________________. These characteristics help determine the size of the population. Recent consensus for the worlds human population is that humans have now reached 7 billion!!!

Sometimes population size is easy to measure. Example: Trees and plants. In other situations it is difficult to measure the population size. This would occur when an animal is _________________________________________ _________________________________________ ____________________________________. In these situations, estimates of population size are made.

Population Density Population density is _________________________________________________ __________________________________________________________________ ___________________________________. It is expressed as the number of individuals per unit area or volume. Example: the population density of humans in the US is about __________________ __________________________________ Example: the population density of humans in Japan is about __________________ ___________________________________ When considering population density the populations _________________________ needs to be considered. Dispersion describes the ____________________________ __________________________________________________________________ ____________________________. Dispersion patterns will depend on the scale at which you observe the population and there are three basic types of dispersion patterns. 1. Clumped Distribution. _____________________________________________ ________________________________________. Can also occur due to ___________________________________________. Examples: Zebras in herds, birds in flocks.

2. Even Distribution (uniform). ________________________________________ ________________________________________. Usually individuals try to get as far away as possible from each other ___________________________ ________________________________________. 3. Random Distribution. ________________________________________ ________________________________________. Random dispersal of organisms ________________ ________________________________________ _________________________. Example: seed dispersal is by the wind and birds. Population Dynamics __________________________ is the amount by which a population’s size changes in a given time. All populations are __________________________ _______________________________. Whether a population grows, shrinks, or remains the same size depends on four processes: ___________________ ________________________________________. The dynamics of a population are also determined by other factors such as Life Expectancy (________________________________________________________) and Age Structure (___________________________________________________ _____________________________). For example, important population processes vary with age. Very old individuals ______________________________________. Populations with a ___________________________________________________ __________________________________________________. This scenario changes for different species as their rate of survival at different stages in life varies. A ____________________________________ is used to illustrate the likelihood of the survival of different species at different ages.

Type I survivorship curve. Humans & elephants - ______________________ _______________________________ _______________________________ ______________________________. Type II survivorship curve. Some birds - _______________________________ _______________________________ _______________________________ ______________________________. Type III survivorship curve. Oysters, salmon, & insects - ___________________________________________________ __________________________________________________________________ _____________________________ Population Growth Rate Populations of organisms change in number over time. _______________________ __________________________________________________________________ ____________________________________. This may result in the complete elimination of a population of organisms or possibly the ______________________ _______________________________________. As previously stated, whether a population grows, shrinks, or remains the same size depends on four processes: ____________________________________________.

Births (b) _____________________________________________________. Deaths (d) ____________________________________________________ ____________________________________________________________. Emigration(e) _________________________________________________ _____________________________________________________________ Immigration(i) _________________________________________________ ___________________________________________________________

When a population changes in number we can calculate its ____________________ using the following equation: r = (( b + i ) - (e + d)) / n In order to figure out the growth rate(r) of a certain population, ________________ __________________________________________________________________ must be added together first. These are the immigrants(i) and the births(b). Next, __________________________________________________________________ are subtracted. These are the emigrants(e) and the deaths(d). This number is then divided by the total number of organisms in the initial population(n).

A _____________________________________ from the formula means __________________________________________, while a _____________________ ______________________ means that __________________________________ __________________________. Solve the following problems: 1) If a population of 5000 plants is on an isolated island (no immigration or emigration), and 400 new plants are sprouting in the population for every 200 that are dying, what is the growth rate of the population? How many plants would there be after 3 years at this growth rate? 2) If a population of 10 000 mice are on the island, and 40 swim off the island while 50 swim on, and 5000 mice are born in the population for every 6000 that are dying, what is the growth rate of the population How many mice would there be after a period of 2 years?

Models of Population Growth When studying how populations grow scientists have developed two basic models to describe how a population might change over time as it grows.

1. The Exponential Model (J curve)

The Exponential Model _________________________ ___________________________________________ __________________________________________. The larger the population gets the faster it grows. It is assumed that the birth rate and death rates remain constant and that _____________________________

___________________________________________________________________________________________________ Predictions Based on Exponential Model. The graph of exponential growth shown below has a characteristic J-shaped curve. Something is said to increase or decrease exponentially if its rate of change must be expressed using exponents. A graph of such a rate would appear not as a straight line, but as ____________________________________________________________ ________________________________. As this model indicates, _______________________________________________ _______________, but, __________________________________. We can use this model to predict that the population will grow indefinitely and at an increasingly rapid rate. Limitations of the Exponential Model. How well does it match the growth pattern of real populations? Real populations ____ grow like this, but under rare conditions and for only _________________________ _____________________. In reality, the population will _____________________ _________________________________. There will be a ____________________ _________________________________________________________________. 2. The Logistic Model (S curve) The Logistic Model builds on the exponential growth model and _________________ _____________________________________ _____________________________________ _____________________________________ _____________________________________ This model incorporates some new terms: Carrying capacity (K) - ___________________ ______________________________________ ______________________________________ ______________________________________ _______________. Steady State _______________________________________________________ ___________________________________________________________________________________________________________________________________. When the population size is small and resources are abundant, the birth rates are high and death rates are low. As the population grows it hits a period of ______________ ___________________. As the population reaches the ecosystems _____________ ________________, the growth rate slows resulting from ____________________

_____________________________________________. For all populations at carrying capacity the birth rate equals the death rate. This population is said to be at a ___________________________ where the ____________________________ _________________________________________________________________________________________________________. This may be the result of reaching the carrying capacity of the environment or in response to other limiting factors. Limitations of the Logistic Model: The logistic model assumes the carrying capacity remains constant. _____________ _________________________________________________________________________________________________________________________________________________________________. In response population sizes will also fluctuate. Population Regulation There are many factors that affect immigration, emigration, births and deaths and consequently the population growth rate. These factors can be categorized into two groups of limiting factors: 1. ________________________________________ or 2. ________________________________________________ 1. Density-independent factors. It has been observed that when there are _________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________. Therefore, abiotic factors are density-independent. Examples: Weather, floods, fires, cold-snap. These factors reduce the population size by the same proportion _______________________________________________ _______________________________________. 2. Density-dependent factors. ___________________________________________________________________________________________________________________________________________________________________________________. Therefore, they are termed density-dependent factors. When populations become crowded organisms have to compete with one another for resources such as food, water, space, mates etc. Competition among members of the same species is a density-dependent limiting factor. The more individuals there are the faster resources become limited. Competition between members of different species is a major force behind evolutionary change. In this case competition results from ____________________

__________________________________________. This is when two or more species ____________________________________________________________ and ______________________________________________________________. When two species compete, both find themselves under pressure from natural selection to change in ways that reduces their competition. Example: Darwin's finches - Several species of birds eat a different size seed. Example: Resource limitations - lack of food. _________________________________________________________________. Density dependent factors will __________________________________________ _________________________________.

Cyclic Population Fluctuations All populations _____________________________________________________. Some of these fluctuations are _________ _________________________________ _________________________________ linked to fluctuations of preditor/prey populations within a given ecosystem. Example: _________________________. Population numbers fluctuate due to the predator-prey interactions. ___________ ________________________________ ___________________________________ ___________________________________ _______________. However, there will soon be ______________________ and as a result of the increased predation, the hare population will decrease ____________________________________________________________________________________________________________________________________________________________________________________. This decrease in lynx population is good for the hare and hare numbers will increase again. This increase will be followed, with a ______________________________________________, leading to a decrease in hare, then a decrease in lynx, and so on. This growth pattern will continue with all populations even if fluctuations are slight. ________________ __________________________________________________________________

Adaptaitons in Preditor-Prey Relationships Natural selection favours adaptations that _________________________________ ________________________ and the ___________________________________

_________________________________. This concept explains many of the interesting features seen amongst organisms. Some examples are: a rattlesnake's keen sense of smell, a spider's webs, sharp teeth in wolves as well as ________________ _____________________________________, sharp thorns in plants and chemical deterrents found in poison oak.

Perils of small populations It is important to note that ____________________________________________ _________________________________________________________________. Environmental disturbances such as storms, fires, floods, or disease can have dramatic effects on small populations. Disease outbreaks can wipe out the entire population. In small populations inbreeding is more likely to occur. When this occurs the offspring of related parents often have fewer offspring, are more susceptible to disease, and have a shorter life span. Inbreeding will also often lead to diseased genetic variability and may reduce the populations ability to adapt. Be sure that you understand that a species ability to survive is based on its biotic potential. Biotic potential is ___________________________________________ ________________________________________________________. Full expression of the biotic potential of an organism is restricted by ________________ __________________________________________________________________. It is generally only reached when environmental conditions are very favorable. A species reaching its biotic potential would exhibit ___________________________ ____________________________________________________________, that is, how many offspring are produced per mother.

Succession

What is Succession? Just as the people living in your neighborhood can come and go, _______________ _____________________________________________________________. One way a community can change is if external conditions shift. If the weather in a certain geographical area suddenly gets colder, certain populations will be better off and will thrive, while others will shrink and disappear.

However, change in communities is not always caused by external factors: _____________________________________________________________________________________________________. The success of a particular population in a particular area will change the environment to the advantage of other populations. In fact, the originally successful population often changes the environment to its own detriment. In this way, the populations within a community change over time, often in predictable ways. ______________________________ ________________________________________________________________________________________________________________. Successional change in a community is the ____________________________________________________ _____________________________________________. Succession can either begin with Primary Succession, which is _________________ ________________________________________________________________________________________________________________________________________________________________________________________, or Secondary Succession, which is the _______________________________________________ __________________________________________________________________ (natural disaster like a forest fire or human activities such as logging). Primary Succession takes much longer (centuries) than Secondary succession (decades). Succession begins when populations move into geographic areas. ________________ __________________________________________________________________ is referred to as a pioneer species. If this pioneer population is successful in its new location, it will change the environment in such a way that new populations can move in (Intermediate species). This will continue until eventually, the community reaches a point where the mixture of populations creates no new changes in the environment. At this point, _______________________________________________________ ________________________________________ are said to make up a climax community. While individuals within a climax community will come and go, _______ ___________________________________________________________________________________________________________________________________.

Succession In Action Imagine a catastrophic event: a forest fire rages through the Okanagan Mountain Park of British Columbia. The fires burn everything and leave behind a barren, rocky expanse. The population of trees that once lived in this area can’t grow back because the fire has changed the ground composition. This rocky ground, however, proves ideal to lichens, the ______________________________________. The lichens colonize the rocks and thrive. As part of their life process, lichens produce acids that ________________________________________________________________ _____________________________. As lichens need solid places to survive: they become victims of their own success. Mosses and herbs are well suited to living in the shallow soil environment created by the lichen, and they ______________________ __________________________________________________________. The mosses and herbs continue to build up the soil. _________________________ _________________________________________________________________. Eventually the land becomes suitable for shrubs and then for trees. The early dominant trees in the community will be species like poplar, which thrive in bright, sunlit conditions. As more trees grow in the area, however, there is less sunlight, and maples, which grow in shade, supplant the sun-starved poplars. The maples eventually dominate the community, because they don’t change the soil composition and thrive in their own shade. __________________________________________ ________________________________________, with maple as the dominant species. ___________________________________________________________ _____________________________________________________________. A term that you should also be familiar with is _____________________________. Keystone Species is __________________________________________________ __________________________________________________________________

_________________________________________________________________.

Keystone species help to support the ecosystem (entire community of life) of which

they are a part. A classic keystone species is a small predator that prevents a

particular herbivorous species from eliminating dominant plant species. Since the

prey numbers are low, the keystone predator numbers can be even lower and still be

effective. Yet without the predators, the herbivorous prey would explode in numbers,

wipe out the dominant plants, and dramatically alter the character of the ecosystem.