Evolution, Selection and Extinction

Environmental Science: Biodiversity and Evolution

Lesson 4: Biodiversity and Evolution

• Environmental Science covers Lesson 4: Biodiversity and Evolution

Day 1 Bell Ringer

• Three examples of biodiversity are required.

Lesson 4.1: Biodiversity and Importance

• This lesson introduces the definition of biodiversity and its significance.
• The lesson aims to describe biodiversity's four components.
• Biodiversity leading to more resilient ecosystems will be explained.
• How biodiversity relates to natural capital will be understood.

Key Terms

• Terms discussed include:
• Biodiversity
• Species diversity
• Genetic diversity
• Ecosystem diversity
• Biome
• Functional diversity
• Insurance hypothesis

Biodiversity and Variety of Life

• Biodiversity, or biological diversity, refers to the variety of life on Earth.
• It encompasses Earth's species.
• Genetic material contained within those species.
• Ecosystems species inhabit.
• Ecosystem processes like energy flow and nutrient cycling.

Species Diversity

• Species diversity is the most common method to study biodiversity.
• It describes the variety of species in an ecosystem and the abundance of each species within it.
• Approximately 2 million species of Earth's organisms have been discovered to date.
• The estimated actual number of species is 7-10 million.
• The total could potentially reach as high as 100 million different species.

Genetic Diversity

• Genetic diversity refers to the variety of genes found in a population or species.
• Greater genetic diversity within a species increases its chances of survival.
• Individuals with favorable traits, such as resistance to disease, have a better chance of survival due to genetic diversity.

Ecosystem Diversity

• Ecosystem diversity refers to the diversity of biological communities on Earth, including deserts, grasslands, forests, lakes, rivers, and wetlands.
• Biomes represent larger geographic regions encompassing several ecosystems.
• Distinct climate and species characterize a biome.

Functional Diversity

• Functional diversity refers to the variety of processes within ecosystems, such as energy flow and matter cycling.
• Multiple species can share the same function within an ecosystem, such as different animal species grazing and sharing the same feeding strategy.
• The insurance hypothesis states that biodiversity ensures ecosystems against a decline in their functioning.
• Several species offer greater guarantees of functioning should others fail.

Biodiversity Builds Natural Capital

• Biodiversity maintains the natural capital that keeps humans alive and supports the economy.
• Humans tap into Earth's biodiversity, with the help of technology, to develop resources like food, medicine, fuel, and building materials.

Day 1 Exit Ticket

• A video about the importance of biodiversity is to be reviewed following which questions will need answering.

Day 2 Bell Ringer

• Discuss how biodiversity helps sustain life on Earth.
• Discuss how a reduction in species diversity might affect the other three components of biodiversity.

Lesson 4.2: Species Roles in Ecosystems

• This lesson explores species' ecological roles within ecosystems.
• Species' ecological niche within an ecosystem will be described.
• Ecologists classify native, nonnative, keystone, and indicator species.
• Threats to keystone species and indicator species and ecosystems they inhabit discussed.

Key Terms - Species Roles

• The lesson will touch on terms like:
• Ecological niche
• Habitat
• Generalist species
• Specialist species
• Native species
• Nonnative species
• Keystone species
• Indicator species

Each Species' Role

• Each species has a unique role determined by the ecological niche or simply niche.
• A species' niche includes everything affecting survival and reproduction in its community.
• The niche covers required water and sunlight, space requirements, food sources, and the temperature tolerance and conditions.

Species and Niche

• A species' niche is distinguished from the species habitat.
• A species habitat is the place or type of ecosystem where it survives and gets the resources it needs.
• Ecologists classify species as either generalist or specialist based on their niche.

Generalist Species

• Generalist species have broad niches.
• They inhabit a variety of places.
• They eat a variety of foods.
• They tolerate a wide range of environmental conditions.
• Examples include:
• Raccoons
• American crows
• Coyotes
• House sparrows
• White-tailed deer

Specialist Species

• Specialist species occupy narrow niches.
• They can only live in one type of habitat.
• They eat only select foods.
• They only tolerate a narrow range of environmental conditions. – Giant pandas and American avocets are good examples.

Relationship Type

• Organisms are classified based on their history in an ecosystem as native and non-native species
• The determination on species being keystone or as indicator is based on the impact a species' behavior has on an ecosystem.

Native Species

• Native species originated in each ecosystem and have adapted to its environmental conditions
• Native species can inhabit multiple ecosystems through migration, without human intervention.
• Australia's koala
• The European Red Squirrel are examples.

Nonnative Species

• Nonnative species were introduced to an ecosystem through natural causes, such as migration, or through human actions
• They are also called alien, exotic, or invasive species.
• Invasive species disrupt ecosystems and replace native species. -Chickens, tomatoes, cattle, and some fish are examples.

Keystone Species

• Keystone species are organisms with a unique role in an ecosystem.
• Ecosystems would dramatically differ or cease to exist without them.
• Keystone species play critical roles in helping to sustain an ecosystem.
• The loss of a keystone species leads to population crashes or extinction of other species.

Keystone Examples

• Mountain lions and wolves control the distribution and population of prey animals, like deer and rabbits.
• They influence the areas the prey animals feed and raise their young.
• Sea otters maintain kelp forests by consuming the sea urchins that destroy them.

Keystone - Alligator

• American Alligators are keystone to the subtropic wetland ecosystems in the southeastern United States.
• They dig holes to hold water during the dry season, which act as refuge for aquatic life.
• They protect game fish through eating predatory.

Keystone - Sharks

• Sharks are crucial in keeping ecosystems functioning.
• Sharks at or near the top of the food web remove sick or injured animals.
• This keeps dead or dying fish and marine mammals from building up.
• They also influence the feeding habits of other animals.

Indicator Species

• Indicator species presence or absence indicates certain environmental conditions.
• Certain species indicate water level issues or air pollution.
• Indicator species are highly sensitive to environmental changes, affected almost immediately by ecosystem change.

Indicator Species

• Frogs and other amphibians are indicators of water and environmental issues.
• Parasites.
• Diseases. -Chemical pollution. –High levels of UV radiation. -Fluctuations in moisture and temperature.

Day 3 Bell Ringer

• Requires explanation about what is meant by the phrase "a niche is a species' way of life"

Lesson 4.3: Life on Earth Over Time

• Explores how life on Earth changes over time through biological evolution.
• The scientific theory of biological evolution explained.
• Genetic variability and natural selection will be described as mechanisms for evolution.
• Limits that natural selection has explored.

Key Terms - Changing Life

• Includes examining:
• Biological evolution
• Natural selection
• Fossil
• Genetic variability
• Mutation
• Adaptation
• Genetic Resistance

Evolution Explains Change

• Biological evolution (or evolution) is the process by which species genetically change over time.
• These changes happen within populations' genes from one generation to the next.

Natural Selection

• Species have evolved from earlier, ancestral species through natural selection.
• Genetic traits allow individuals to survive and reproduce under certain environmental conditions.

Fossils

• Fossils gives insight into life on Earth.
• Fossils are petrified remains or traces of skeletons, bones, teeth, shells, leaves, and seeds.

Finding Fossils

• Fossils can consist of impressions left behind in rock after an animal dies, including its tracks, trails or burrows.
• Fossil evidence is found in sedimentary rock like limestone and sandstone.
• Ice core samples from drilling glacial ice at Earth's Poles and mountaintops sometimes contain fossil evidence.

Evolutionary Scientists

• Charles Darwin (1809-1882) and Alfred Russel Wallace (1823-1913) independently proposed natural selection as a biological evolution mechanism.
• Darwin gathered his evidence by studying the Galapagos Islands and other locations around the world.
• Darwin in 1859 published On the Origin of Species using Natural Selection.

Genetic Variability

• Genetic variability refers to the variety in the genetic makeup of individuals in a population.
• Mutation primarily results in this factor.
• A mutation refers to a permanent change in the DNA sequence in a gene of any inherited cell.

Mutations Lead to Variability

• Most mutations are random changes in a coded gene.
• Some mutations are exposure to external courses like radioactivity, UV radiation, and certain natural and man-made chemicals called mutagens.

Natural Selection

• Natural selection explains how populations have evolved in response to environmental condition changes by genetically changing the overall population.
• It allows increased survival and reproduction for well suited individuals.

Adaptation

• Is any heritable trait that gives individuals an advantage compared to other individuals in each population.

Genetic Resistance

• Genetic resistance results from one or more organisms in a population being predisposed to tolerate exposure to a condition that would normally be fatal.
• Genetic resistance can develop fast in bacteria and insects that produce large numbers of offspring.

Limits to Natural Selection

• 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 originate from random mutations.
• Even if a heritable trait is present, the adaptation may be limited by the population's reproductive capacity.

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: Factors Affecting Biodiversity

• Exploring factors that impact biodiversity, including:
• Speciation and extinction determining Earth's biodiversity.
• Artificial selection and genetic engineering allow humans to select species' traits.

Key Terms - Biodiversity Factors

• Will examine these terms:
• Speciation
• Geographic isolation
• Reproductive isolation
• Artificial selection
• Genetic engineering
• Biological extinction
• Endemic species
• Background extinction rate
• Mass extinction
• Synthetic biology

Speciation

• Speciation causes completely new species over time.
• It happens in species that migrate great distances or are separated by a physical barrier.
• The separation is called isolation.
• Isolation can be:
• geographic isolation
• reproductive isolation.

Geographic Isolation

• Geographic isolation - two groups physically separated from each other.
• An example - part of a population migrates in search of food.
• Other examples - natural forces separate animals from their environment.
• hurricanes.
• earthquakes.
• volcanic eruptions.

Human Activity and Geography

• Activities key players in geographic isolation include:
  • the building of hydroelectric dams.
  • clearing of forests.
• Human species are being prevented from evolving due to physical barriers erected.

Day 6 Bell Ringer

• To identify and explain geographic isolation not caused by humans.

Reproductive Isolation

• Reproductive isolation stops genes from sharing with one another between populations.
• Random and natural selections can lead to a specific population trait.
• Live fertile offspring, these species can integrate and evolve to become independent again.

Eliminating species

• If a life species can not live or move from environmental changes the species will face extinction.

Endemic Species

• Endemic species are extremely vulnerable to extinction.
• Generally found on islands or in isolated areas.
• They live in the tropical rainforest and have specialized roles in that ecosystem

Extinction

• All species will become extinct.
• Shows only 99.8% is extinct, background extinction rate. Slow decline, low-rate.

Mass Extinction

• Some species will face great danger due to:
• Mass extinction is a called life reducing life reducing event.
• Species will evolve to recover from it. - Mass Extinction
• Scientists have found evidence of 50-90% extinction from new habitats

Traits humans select species

– Humans manipulate to produce the type of food they want.

• Food with high nutrition, meat production

Artificial Selection

• The action of humans genetically producing certain plants. By existing and cross breeding.
• Most grains, fruits, crossbred produced.
• Cows produce more, food becomes more available

Artifical Selection

• Comes from the mustard family.
• Broccoli, cabbage, kale.
• Cows, chickens, animals become hybridized from jungle fowl for food.

Day 7 Bell Ringer

• Charles Darwin - The strongest of species do not survive the most, but the most responsive to change.

Gene Engineering

• Scientists can use gene engineering - evolutionary speed.
• Scientist transfer from one species and alter and manipulate organism.
• Genetically Modified Genetically Modified.

Genetic Engineering -Examples

GMO - genetically modified - grains, rice, corn, wheat, barley, soy.peanuts. vegetables. Animal - Pigs Cattle

• Chickens Fish
• Mice

###Synthetic Biology

• A rapid form.
• Large scale production for more creation of synthetic chemicals.

Explore Darwin's survival factors, genetic engineering vs. breeding, and synthetic biology applications. Learn about pest-resistant corn, GMOs, species extinction, and the impact of mass extinctions on new species. Understand the key differences between artificial and natural selection.