Environmental Science Lesson 4 Biodiversity & Evolution PDF

Lesson 4: Biodiversity and Evolution Environmental Science 1  Day 1 Bell Ringer Give 3 examples of biodiversity: ○ _______________________ ○ _______________________ ○ _______________________  Lesson 4.1 What is Biodiversity and Why is...

Lesson 4: Biodiversity and Evolution Environmental Science 1  Day 1 Bell Ringer Give 3 examples of biodiversity: ○ _______________________ ○ _______________________ ○ _______________________  Lesson 4.1 What is Biodiversity and Why is it Important?  What you will learn… How to describe the four components of biodiversity. How to explain biodiversity leading to more resilient ecosystems. Understand how biodiversity relates to natural capital.  Key terms Biodiversity Species diversity Genetic diversity Ecosystem diversity Biome Functional diversity Insurance hypothesis  Biodiversity and the Variety of Life Biodiversity, or biological diversity, is the variety of life on Earth. This includes all of Earth’s species, the genetic material those species contain, the ecosystems they live in, and the ecosystem processes such as energy flow and nutrient cycling.  Species Diversity Species diversity is the most common way to study biodiversity. ○Species Diversity is the component of biodiversity that describes both the variety of species present in an ecosystem and their abundance within their ecosystem. To date, scientists have discovered about 2 million species of organisms on Earth, with an estimated actual number of 7-10 million, and could even be as high as 100 million different species. Genetic Diversity Genetic diversity is the variety of genes found in a population or a species. ○ Species have a greater chance of survival if there is greater genetic diversity within a species. There is a greater chance of individuals possessing favorable traits needed to survive, such as resistance to disease.  Ecosystem Diversity Ecosystem diversity is the Earth’s diversity of biological communities such as deserts, grasslands, forests, lakes, rivers, and wetlands. Several ecosystems are represented through larger geographic regions called biomes. ○ A biome is characterized by a distinct climate and certain species (especially vegetation) that could survive there.  Functional Diversity Functional diversity is the variety of processes such as energy flow and matter cycling that occurs within ecosystems. ○ More than one species may share the same function, such as two species of animal are both grazers and share the same feeding strategy. A concept called the insurance hypothesis states that “biodiversity ensures ecosystems against a decline in their functioning because many species provide greater guarantees of functioning even if others fail.  Biodiversity Builds Natural Capital Biodiversity is key to maintaining the natural capital. This keeps humans alive and helps support the economy. With the help of technology, humans tap into Earth’s biodiversity to develop resources such as food, medicine, building materials, and fuel. Day 1 Exit Ticket Watch the video and then answer the question. Why is biodiversity so important? - Kim Preshoff Video Link: https://tinyurl.com/35xpb33e  Day 2 Bell Ringer How does biodiversity help sustain life on Earth? How might a reduction in species diversity affect the other three components of biodiversity?  Lesson 4.2 What Roles Do Species Play in Ecosystems?  What you will learn.... How to describe a species’ ecological niche within an ecosystem. How ecologists classify native, nonnative, keystone, and indicator species. How threats to keystone species and indicator species in turn threaten the ecosystems they inhabit.  Key Terms Ecological niche Habitat Generalist species Specialist species Native species Nonnative species Keystone species Indicator species  Each Species Plays a Role in its Ecosystem Species and Niche ○Each species has a role that is very specific to the ecosystem. Each role is determined by the ecological niche or simply niche. A niche is a species' way of life in its community and includes everything that affects the survival and reproduction of that species. Includes the amount of water and sunlight that is needed, the amount of space required, what it eats and what eats it, and the temperature as well as other conditions it can tolerate.  Species and Niche (cont..) A species' niche is not the same thing as a species habitat. A habitat is the place, or type of ecosystem, in which a species lives and obtains what it needs to survive. Ecologists use a species' ecological niche to classify a species as being either generalist or specialist.  Generalist Species A generalist species has a very broad niche. A generalist can live in several different places, eat a variety of foods, and can often tolerate a wide range of environmental conditions. ○Examples Raccoon American crows Coyotes House sparrows White-tailed deer  Specialist Species A specialist species occupies only a narrow niche. Specialists are only able to live in one type of habitat, eat only select foods, and can only tolerate a narrow range of environmental conditions. ○Examples Giant panda American avocet  Species and Ecosystem Ecologists further classify organisms by their history in an ecosystem. These are native and non-native species. The impact a species’ behavior has on an ecosystem determines whether that species is a keystone species or an indicator species.  Native Species Native Species are species that naturally originated in each ecosystem and have become suited to the environmental conditions of that ecosystem. Native species will live in an ecosystem, though can be considered native in several ecosystems due to migration, without human intervention. ○Examples Koalas in Australia European Red Squirrel in Europe Nonnative Species Nonnative species were introduced into an ecosystem through either natural causes, such as migration, or through human actions, either accidental or deliberate. Nonnative species are also referred to as alien species, exotic species, or invasive species. Invasive species are those that disrupt an ecosystem or replace a native species. ○Examples Chickens Tomatoes Cattle Some fish  Keystone Species A keystone species is an organism that has a unique role in an ecosystem. Without keystone species, ecosystems would be dramatically different or cease to exist. Keystone species play several critical roles in helping to sustain an ecosystem. The loss of a keystone species could lead to other species’ populations having a population crash or even going extinct.  Mountain Lions and wolves help control the distribution and population of prey animals such as deer and rabbits by influencing where these species feed and raise their young. Sea otters help sustain kelp forests by Keystone feeding on sea urchins, which destroy kelp plants as they graze on them. Species Examples  Keystone Species – American Alligator American Alligators are keystone to the subtropic wetland ecosystems in the southeastern United States. They dig deep holes to hold water during the dry season, these depressions hold aquatic life as refugees during that time. They also help protect game fish by eating predatory gar. They have many other parts that make them a keystone species.  Keystone Species - Sharks Certain sharks play a crucial role in keeping ecosystems functioning. Sharks feeding at or near the top of their food web removes sick or injured animals. This ecosystem service keeps dead or dying fish and marine mammals from building up. They also influence the feeding habits of other animals.  Indicator Species Indicator Species are the species whose presence or absence indicates the quality of characteristics of certain environmental conditions. ○Example Certain species are indicators of water level or air pollution. Indicator species are highly sensitive to environmental changes and are affected almost immediately by ecosystem change.  Indicator Species - Frogs Frogs and other amphibians are very susceptible to parasites and diseases, viral and fungal. They are also good indicators for chemical pollution, high levels of UV radiation, and even slight changes in temperature or moisture.  Day 3 Bell Ringer What is meant by the statement "A niche is a species' way of life?”  Lesson 4.3 How Does Life on Earth Change Over Time?  What you will learn.... How to explain the scientific theory of biological evolution. How to describe genetic variability and natural selection as mechanisms for evolution. Understanding that natural selection has limits.  Key Terms Biological evolution Natural selection Fossil Genetic variability Mutation Adaptation Genetic Resistance  Evolution Explains How Organisms Change Over Time Biological evolution, or evolution, is the process by which species genetically change over time. These changes happen within the genes of populations of organisms from one generation to the next. Natural Selection According to scientific theory, species have evolved from earlier, ancestral species through natural selection. This process allows individuals to pass on certain genetic traits that are more likely to allow them to survive and reproduce under certain environmental conditions. BioBlitz Finds 2,300+ Species in Golden Gate Parks | National Geographic Day 4 Bell Ringer Identify three objects that can be fossilized. ______________________________ ______________________________ ______________________________ Fossils What we know about the history of life on Earth comes from fossils. Fossils are preserved remains or traces of prehistoric organisms. Fossils are petrified remains of skeletons, bones, teeth, shells, leaves, and seeds.  Where are Fossils found? There may even be impressions in rock that such structures left behind. They can even be impressions left behind from animal tracks, trails, and burrows. Scientists have even found fossils evidence in layers of sedimentary rock such as limestone and sandstone. Scientists have also found samples in ice core samples found from drilling glacial ice at Earth's Poles and mountaintops. Evolutionary Scientists In 1858, Charles Darwin (1809-1882) and Alfred Russel Wallace (1823-1913) independently proposed the concept of natural selection as a mechanism for biological evolution. Darwin gathered the evidence by studying the Galapagos Islands as well as other locations around the world. In 1859, Darwin published his book On the Origin of Species using Natural Selection.  Genetic Variability One factor that is necessary for evolution to occur is genetic variability. Genetic Variability refers to the variety in the genetic makeup of individuals in a population. This factor primarily results from mutation. A mutation is a permanent change in the DNA sequence in a gene of any inherited cell.  How mutations lead to genetic variability.... Most mutations occur from random changes in the DNA's coded genetic instructions and occur in only a tiny fraction of the million divisions of cells. Some mutations result from exposure to external sources such as radioactivity, UV radiation, and certain natural and human-made chemicals called mutagens.  Natural Selection The scientific concept of natural selection explains how populations have evolved in response to environmental condition changes by way of changing the overall genetic makeup. Natural selection allows for increased survival and reproduction for individuals who are better suited to the environmental conditions.  Adaptation Adaptation, or adaptive trait, is any heritable trait that gives an advantage to an individual over the other individuals in each population.  Genetic Resistance Genetic resistance is the result of one or more organisms in a population being predisposed to tolerate exposure to some condition that normally would be fatal. Genetic resistance can develop quickly in populations of organisms such as bacteria and insects that produce large numbers of offspring in a short amount of time.  Limits to Natural Selection First, a change in environmental conditions can lead to such an adaptation only if genetic traits are already present in a population's gene pool or if they come from random mutations. Second, if a heritable trait is present in a population, the pace at which the population can adapt may be limited by reproductive capacity. ○ Examples Mosquitos Dandelions Rats Bacteria  Day 5 Bell Ringer How does evolution explain the diversity of life on Earth? What are the two limits of natural selection?  Lesson 4.4 What Factors Affect Biodiversity? What you will learn.... Be able to explain how speciation and extinction determine Earth's biodiversity. An understanding of how artificial selection and genetic engineering allow humans to select species' traits.  Key Terms Speciation Biological extinction Geographic isolation Endemic species Reproductive isolation Background extinction Artificial selection rate Genetic engineering Mass extinction Synthetic biology  Speciation Give Rise to New Species Speciation is when natural selection gives way to a completely new species over some time. Speciation typically happens in species that migrate great distances or a physical barrier separates two or more populations of a given species. ○This separation is called isolation. There are two kinds of isolation, geographic isolation, and reproductive isolation.  Geographic Isolation Geographic isolation is when two different groups of the same species become physically separated from one another. ○An example is when part of a population migrates in search of food and start living in an area with different environmental condition. ○Another example is when animals are separated due to natural forces, such as hurricanes, earthquakes, or volcanic eruptions. Human activity that causes Geographic isolation Human activities are major key players in geographic isolation. ○Activities such as the building of hydroelectric dams or clearing of forests will cause physical barriers for certain species. Day 6 Bell Ringer Identify and explain an example of geographic isolation that is NOT caused by humans.  Reproductive Isolation Reproductive isolation is caused once the geographically separated populations stop having genes shared between the populations. ○ Random mutations as well as other changes in response to natural selection will begin to operate independently as gene pools of the separated populations begin to change to fit the new environment. Some of these species may no longer be able to interbreed and still produce live, fertile offspring if the populations were able to come back together.  Extinction Eliminates Species Biological extinction, or extinction, is when an entire species ceases to exist. This can happen through environmental condition changes, if a species cannot adapt to survive those changes, or move to another region, these species will become extinct.  Endemic Species Endemic species are extremely vulnerable to extinction. These organisms may be found on islands or other isolated areas. They may also only live in tropical rainforests and have very specialized roles in that ecosystem.  Extinction Fossils and other scientific evidence indicate that all species will eventually become extinct. ○Evidence shows that 99.8% of all species that have existed on Earth are already extinct. Over the life of Earth, most species have slowly disappeared at a naturally low rate. This is called the background extinction rate. Mass Extinction There have been periods where life on Earth has been greatly reduced due to an event. This is called a mass extinction. Scientists have found evidence of 5 major mass extinctions where 50-90% or more of all life on Earth has been eradicated. Mass extinctions give way to new species to emerge that can fill unoccupied ecological niches or newly created ones.  Humans Select Species' Traits Humans have developed methods to manipulate and combine genes of species to get a desired trait to fulfill a human need. The two ways that humans can do this manipulation are through artificial selection and genetic engineering.  Artificial Selection Artificial selection is when humans change the genetic characteristics of populations with similar genes. This is done by first selecting one or more desirable genetic traits that already exist in a population, whether it is plant or animal. ○This can be done by crossbreeding. Most grains, fruits, and vegetables we have today are a product of crossbreeding. ○These foods produce more crops and cows who have been crossbred produce more milk or meat. Artificial Selection Examples Wild mustard plant ○ Vegetables that came from the mustard plant. Brussel sprouts Cabbage Cauliflower Broccoli Kale Animal ○ Cows bred to produce more milk ○ Original chickens were hybridized from 2 different junglefowl. Day 7 Bell Ringer In 1809, Charles Darwin said: “It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.” Consider Darwin’s quote and explain it by citing at least one specific example.  Genetic Engineering Scientists use genetic engineering to speed up evolutionary steps. This is done by manipulating genes to select desirable trait or traits or eliminate undesirable ones. Genetic engineering allows scientists to alter an organism's DNA by adding, deleting, or changing segments through gene splicing. Scientists can also transfer genes from one species to another that would not breed in nature. These organisms are considered GMOs, genetically modified organisms. Examples of Genetic Engineering GMO, genetically modified organisms ○ Plant Grains, rice, corn, wheat, barley, soy Peanuts Vegetables ○ Animal Pigs Cattle Chickens Fish Mice  Synthetic Biology A new and rapid form of genetic engineering is synthetic biology. While most GMO items contain only one gene that is modified, synthetic biology allows for large-scale gene production. This allows the creation of new cells, tissues, organisms, and devices. Synthetic biology is used primarily in pharmaceuticals, diagnostic tools, chemistry, and biofuel production.