BIOLOGY

POWERPOINT SLIDESHOWGrade 9 Science

BIOLOGICALBIOLOGICALDIVERSITYDIVERSITY

Supporting Science Textbook Content while enriching the Learning Process in Junior High/Middle SchoolSupporting Science Textbook Content while enriching the Learning Process in Junior High/Middle School

BIOLOGYConcept MapConcept Map

Shows the conceptsShows the conceptscovered covered

within the framework within the framework of this unitof this unit

BiologicalBiologicalDiversityDiversity

Grade 9Grade 9

BIOLOGICAL DIVERSITY - Outline

Slides Key Concept Categories

4 - 12 BIODIVERSITY - Types & Classification

13 - 15 ADAPTATIONS - Structures & Functions

16 - 18 NICHE

19 - 23 SURVIVAL

24 - 27 VARIATION

28 - 35 REPRODUCTION

36 - 39 DNA

40 - 46 GENETICS

47 - 54 BIODIVERSITY - REDUCTION

55 - 56 ARTIFICIAL SELECTION

57 - 59 BIODIVERSITY - PRESERVATION

BIODIVERSITY - Ecosystem Diversity

“Biodiversity is the variety of species and ecosystems on the Earth and the ecological processes of they are a part of.”

Living things interact with non-living (abiotic) and living (biotic) parts of the ecosystems they share. As these abiotic and biotic factors vary from

one ecosystem to another, ecosystem diversity refers to these differences.

Variations between and within ecosystems around the world affect the types and numbers of species that can live in each of these ecosystems.

To determine the biological diversity of an area, biologists use a measurement called a diversity index. This compares the diversity of species in a certain area with the total number of organisms in that same area, or ecosystem. It is primarily used to check on the health of an ecosystem – a healthy ecosystem has a high diversity index.

Mountain Pine Beetle

Destroys pine trees by spreading a blue-stain fungal disease as it bores through

the tree. The tree eventually dies.

BIODIVERSITY - Ecosystem Value

Having variation in an ecosystem enables some of the organisms in that ecosystem to survive because of their higher level of resistance and survival adaptations, when certain species die off. This is important in order to maintain the ecosystem. Sacrificing one part of the ecosystem to save the main parts is also necessary sometimes.

This is why foresters might decide to burn one part of a forest to save the part of the forest that they know will be able to survive other factors that are threatening to destroy the entire forest.

A species is a group of organisms that have the same structures and can reproduce with one another.

Species Diversity is the number of different species in a particular area (also referred to as species richness ) weighted by some measure of abundance such as number of individuals, or biomass. However, it is common for biologists to speak of species diversity even when they are actually referring to species richness.

Another measure of species diversity is the species evenness, which is the relative abundance with which each species is represented in an area.

bacteria cowbird red fox tiger salamander

BIODIVERSITY - Species Diversity

An ecosystem where all the species are represented by the same number of individuals has high species evenness. An ecosystem where some species are represented by many individuals, and other species are represented by very few individuals has a low species evenness.

The most successful life form seems to be the insect. There are many different species that can potentially help other species, like the Pacific Yew Tree, by producing medicines.

Biological diversity is important for the health and survival of natural communities.

BIODIVERSITY - Species Diversity

Taxol, found to be effective in controlling different types of

cancers, is extracted from the bark of the

Pacific Yew Tree.

BIODIVERSITY - Genetic Diversity

Genetic diversity, a form of biodiversity, is the variety of different types of genes in a species or population. Genetic diversity refers to certain variations between members of a population.

Genetic diversity is variation of individual genes, which provides an opportunity for populations of organisms to adapt to their ever-changing environment.

The more variation, the better the chance that at least some of the individuals will have a variation that is suited for the new environment, and will produce offspring with that variation, so that they can, in turn, reproduce and continue the population into subsequent generations.

With the interdependence between biological and genetic diversity; changes in biodiversity result in changes in the environment, requiring subsequent adaptation of the remaining species. Changes in genetic diversity, particularly loss of diversity through loss of species, results in a loss of biological diversity.

the banded snail

BIODIVERSITY - Community Diversity

Community Diversity occurs within populations of organisms living within a particular ecosystem.

Distribution - When individuals of the same species live within the same area and share the same resources, a population of exists. When a number of different populations share a common ecosystem, a community exists. Populations and communities are not distributed evenly on the Earth. The pattern of distribution is much the same as the overall biodiversity of our planet. More variety and numbers of populations and communities near places where it is warm (tropical rainforests and coral reefs) and less variety and numbers where it is cold (Arctic and Antarctic).

BIODIVERSITY - Community Diversity

In northern Canada there are large populations of those species found there, but there are not as many different plant and animal species as there are in other parts of Canada. Large herds of caribou, polar bears, wolves and millions of arctic hare make up the majority of the animals you will find.

The species of wolf, and polar bear are also found in Russia and northern Europe.,

Canis lupus, Ursus maritimus

,

In contrast, hundreds of thousands of species (in small populations) can be found in the rainforests of Central and South America. The reason that Canada supports large populations, with less diversity is the extreme environment and seasonal variations, which restrict their food supply. Organisms living in this ecosystem have a broad niche with adaptations that enable them to survive the extreme changes occurring there. These species are considered to be generalists – able to spread over large areas.

Linnaean Taxonomy was developed by Carolus Linnaeus and is used as the scientific name of the organism. The greatest innovation of Linnaeus, and still the most important aspect of this system, is the general use of binomial nomenclature, the combination of a genus name and a single specific epithet to uniquely identify each species of organism. For example, the human species is uniquely identified by the binomial ‘Homo sapiens’. No other species of animal can have this binomial. The naming of each organism uses the genera (genus) and species (species) to identify each organism and how they are related to each other organism.

This classification system was much more reliable than previous systems, because it used structural characteristics of the organism. Before Linnaean taxonomy, animals were classified according to the way they moved, and their habitat.

All species are classified in a ranked hierarchy, originally starting with kingdoms although domains have since been added as a rank above the kingdoms. Kingdoms are divided into phyla (singular: phylum) — for animals; the term division, used for plants and fungi, is equivalent to the rank of phylum. Phyla (or divisions) are divided into classes, and they, in turn, into orders, families, genera (singular: genus), and species (singular: species).

BIODIVERSITY - Classification System

All organisms have been classified into 5 Kingdoms based on their structural differences.

Animalia (animals)Plantae (plants)Fungi (yeasts, moulds and

mushrooms)Protista ( mostly single-celled

organisms)Monera (bacteria)

Each of these 5 Kingdoms are then further classified as …Kingdom

phylumclass

orderfamily

genusspecies

A species is a particular group of organisms that have the same structure and can reproduce with each other

BIODIVERSITY - Classification System

The special characteristics that enable plants and animals to be successful in a particular environment are called adaptations. 

Camouflage, as in a toad's ability to blend in with its surroundings, is a common example of an adaptation.

The combination of bright orange and black on a monarch butterfly is an adaptation to warn potential predators that the butterfly is poisonous and prevent it from being eaten.

Adaptations afford the organism a better chance to survive in its surroundings. These special features have evolved over long periods of time, through the process of natural selection.

ADAPTATION - Structures and Functions

All animals live in habitats. Habitats provide food, water, and shelter which animals need to survive, but there is more to survival than just the habitat.

Animals depend on their physical features to help them obtain food, keep safe, build homes, withstand weather, and attract mates.

These physical features are called called physical adaptations.

Physical adaptations do not develop during an animal's life but over many generations. The shape of a bird's beak, the number of fingers, color of the fur, the thickness or thinness of the fur, the shape of the nose or ears are all examples of physical adaptations which help different animals to survive.

An example of this are the finches Darwin discovered and studied on the Galapagos Islands

ADAPTATION - Structures and Functions

ADAPTATION - Structures and Functions

NICHE

A niche describes the interrelationships of a species or population in an ecosystem. It includes how a population responds to the abundance of its resources and enemies (e. g., by growing when resources are abundant, and predators, parasites and pathogens are scarce) and how it affects those same factors (e. g., by reducing the abundance of resources through consumption and contributing to the population growth of enemies by falling prey to them).

The abiotic or physical environment is also part of the niche because it influences how populations affect, and are affected by, resources and enemies.

The description of a niche includes descriptions of the organism's life

history, habitat, and place in the food chain. No two species can occupy the same niche in the same environment for a long time.

Sort of like, each piece of a puzzle can only fit in one spot, in the overall picture.

NICHE - Relationships of organisms

Each and every species depends on many other species within an environment in order to survive and prosper.

Food Chain Food Web Food Pyramid

These represent different types of ongoing relationships between and among all organisms, within a particular environment.

Resource Partitioning,

Differentiation

or Separation

is the action which enables competing species to share resources by accessing these resources in different ways.

This natural selection process drives competing species into different patterns of resource use or different niches. The process allows two species to partition certain resources so that one species does not out-compete the other as dictated by the competitive exclusion principle; thus, coexistence is obtained through the differentiation of their realized ecological niches.

NICHE - Distribution of Ecosystem Resources

SURVIVAL - Interdependence of Species

Interdependence is about or when a species depends on other species to perform different roles. All living organisms are included.

Species interdependence is self-evident - the subsystems in a system constitute the ecology and the balance it maintains, while the population-groups and the symbiotic relations existing and evolving within the system demonstrate the 'interdependence'.

A different type of interdependence is an association, within a certain population, between members of different species. There are different types of symbiotic relationships:

Commensalism – in which one of the participating members benefits, but the other does not, and there is no harm done to that organism.

(barnacles on a whale)

Mutualism – both organisms benefit from the relationship. (lichen growing in the Arctic Tundra - algae and fungi - benefit each other)

Parasitism – one organism benefits while the other organism (the victim) is harmed. (the parasite usually doesn’t kill the host, because the host represents the parasite’s food supply.

(tapeworm in a human host)

SURVIVAL - Interdependent Relationships - Symbiosis

Interspecies competition happens when two or more species need the same resource. This type of relationship helps to limit the size of populations, of the competing species.

Species PopulationLimiting Factors

Survival Factors

Resource partitioning is the action, which enables competing species to share the resources by accessing these resources in different ways, involving less direct competition.

SURVIVAL - Interdependence Of Species

SURVIVAL - Natural Selection

Natural selection happens when factors in the environment determines, or ‘selects’ which individuals, within a species, will be able to survive. Many organism have adaptations that defy our understanding of life. Scientists therefore hypothesize that life may exist in the harsh environments on other planets. Living in an environment at 110oC or -35o C is rare, but possible because of adaptations organisms have to live in these extremes.

If they are able to live long enough to reproduce, then those individuals with their ‘survival adaptations’ (characteristics) will have offspring with similar survival characteristics.

Tube worms live on the ocean floor, near black smokers, where volcanic vents make the temperature extremely hot.

Antarctic springtail are arthropods that live in extreme cold, by producing a kind of antifreeze in its tissues.

Snow algae have cell membranes adapted to cold temperature, making their own food by photosynthesis. The red color protects them from the intensity of the sun on the snow.

SURVIVAL - Environmental Change

Some of the most immediate effects of recent climate change are becoming apparent through impacts on biodiversity.

The life cycles of many wild plants and animals are closely linked to the passing of the seasons; climatic changes can lead to interdependent pairs of species (e.g. a wild flower and its pollinating insect) losing synchronization, if, for example, one has a cycle dependent on day length and the other on temperature or precipitation.

The Life Cycle of the Butterfly

In principle, this could lead to extinctions or changes in the distribution and abundance of species

VARIATION

Variation within a population, of a single species, is called variability. Variability is important if there is a sudden or drastic change in the environment, in which the species lives.

When a species has a great deal of variation, then, some of the individuals within that species will likely survive when there is change.

Examples of variability include:

Red fox (color of coat) Antibiotic resistance (bacteria)

Banded snail (color of shell)

VARIATION - Inherited or Non-Inherited

Variation is one of the most critical aspects of species survival. This variation may not always be as easy to find as color usually is, because it may be a behavioral tendency or a genetic (cellular code) modification that enables some individuals within a species to survive, while others, of the same species, will perish.

Inherited (heritable) characteristics are those traits which are passed on to offspring directly from their parents. These traits are passed on by way of the genetic material that is combined from the parents during the process of sexual reproduction.

Heritable traits include, structural and distinguishing characteristics, such as eye color, hair type, skin color and earlobes.

Not all characteristics are inherited. Some depend entirely on the environment. Non-inherited characteristics are acquired and not necessarily passed on from generation to generation. Athleticism, artistic ability, leadership qualities are all learned during the early years of life.

Some variations may be influenced by interactions with the environment. These variations are also non-inherited. Examples include: change in the pigmentation of skin color throughout the seasons due to the sun, height and weight can be influenced by diet. Scars, injuries, clothing, hairstyle, make-up, and cosmetic surgery may change a person’s characteristics, but they are not caused by genetics.

One way that scientists study the relationship between genetics and the environment is to observe the similarities and differences between identical twins that have been separated at birth and raised in different environments.

The interactions between a person’s genetics and the environment are very complex and are constantly being debated.

VARIATION - Inherited or Non-Inherited

VARIATION - Discrete or Continuous

Discrete variations are differences in characteristics that have a definite form. This includes those individuals, within a species, that have either one characteristic, or the single, other variation, of the characteristic. Examples of discrete variation include: tongue rolling ability, blood groups, earlobe attachment, hairline, etc.

Continuous variations are differences in characteristics that have a range of possible variations. The multitude of variations may include such traits as: height, shoe size, hand span, skin color, hair color, etc.

Asexual reproduction involves only one parent. All of the offspring are identical to the parent. There are different types of asexual reproduction:

Binary Fission - only single-celled organisms reproduce in this way. The cell splits into two cells and each one is identical. (bacteria, amoeba, algae)

Budding - the parent organism produces a bud (a smaller version of itself), which eventually detaches itself from the parent and becomes a self-sufficient individual - identical to the parent. Coral also reproduces in this way, but do not detach themselves (hydra, yeast, coral)

Spore Production - spores are similar to seeds, but are produced by the division of cells on the parent, not by the union of two cells. One parent may produce many spores, each of which will grow into a new individual, identical to its parent. (fungi, green algae, moulds, ferns)

Vegetative Reproduction - is the reproduction of a plant not involving a seed, including; cuttings, runners, suckers, tubers. (coleus plant, spider plants, strawberries, aspen, potatoes)

REPRODUCTION - Asexual Reproduction

Sexual reproduction in animals involves gametes (reproductive cells that have only one role - to join with another gamete during reproduction).

The male gametes are called sperm cells, and the female gametes are called egg cells (ova). During mating, the sperm cell and the egg cell unite to form a fertilized combination of cells called a zygote. This zygote is the first of many cells of a new individual. This zygote will begin to divide into two cells and this continues to be repeated over and over resulting in the development of an embryo. This embryo develops into a multi-cellular organism inside the female (in most mammals) or, outside (in an egg shell) in other animals.

REPRODUCTION - Sexual Reproduction - Animals

Sexual reproduction in plants involves gametes as well, male gametes and female gametes joining, during fertilization, to produce a zygote and then an embryo. Most plants produce both male and female gametes, while some produce one or the other only.

Pollen contains the male gametes and is found on the stamen. Ovules contain the female gametes and are found in the pistil. Pollination occurs when pollen is transferred from the anther of the stamen to the stigma of the pistil.

Cross-pollination occurs when pollen from one plant is carried to the stigma of another plant by wind, water or animals (bees or butterflies).

Cross-fertilization occurs when a grain of the pollen forms a long tube, which grows down the style into the ovary. Gametes unite to produce a zygote, which then develops into an embryo. This usually happens inside a seed, protecting the embryo and providing food (cotyledon) for the embryo when growing conditions are right. Plants which are produced, as a result of cross-fertilization, are not identical to either plant.

REPRODUCTION - Sexual Reproduction - Plants

Organisms That Reproduce Sexually & Asexually Most plants that produce seeds can also reproduce asexually (cuttings, runners). Depending on the environmental conditions the amount of energy varies, enabling the plant organism to control its population.

Sponges and Hydra are organisms that can reproduce both sexually and asexually.

Most plants that produce seeds can also reproduce asexually (cuttings, runners). Depending on the environmental conditions the amount of energy varies, enabling the plant organism to control its population.

Mosses produce asexual spores in the early part of their life cycle and then egg and sperm cells are produced in a later part of the same cycle.

REPRODUCTION - Asexual and Sexual Reproduction

Advantages and Disadvantages of Asexual and Sexual Reproduction

Variation usually helps a species survive when the environment changes.

Asexual reproduction does not require any specialized cells to produce a new plant. It can therefore produce many plants very quickly. This is an advantage in places where the environment doesn't change very much (bacteria). By building a large population of organisms very quickly the species is able to thrive. The great disadvantage is that when the environment changes, all of the organisms will die, if they do not have the ability to adapt to the change.

Sexual reproduction has the advantage of providing lots of variation within a species, helping it to survive when the environment changes. The main disadvantage is that this process takes a lot of energy. This means that they can only produce small populations.

REPRODUCTION - Asexual and Sexual Reproduction

Asexual reproduction involves only one parent. All of the offspring are genetically identical to the parent. In single celled organisms, binary fission enables the parent cell to split its contents equally between the two new cells. Prior to this division, the parent cell duplicates its DNA and when the split takes place each new cell receives a complete exact copy of the DNA, of the parent.

In multi-cellular organisms the process that produces two new cells with the same

number of chromosomes is called Mitosis.

REPRODUCTION - Cell Division and Asexual Reproduction

Sexual reproduction usually involves two individual organisms. The offspring that are produced from this union have genetically different characteristics, half from one parent and the other half from the other parent - making a unique offspring. During sexual reproduction, the specialized sex cells (gametes) unite to form a zygote, which develops into the new organism. When a male gamete and a female gamete unite, meiosis takes place.

Meiosis is a type of cell division that produces cells with only half

the DNA of a normal cell. This process involves two cell divisions, not one.

REPRODUCTION - Cell Division in Plants and Animals

REPRODUCTION - Comparison of Meiosis & Mitosis

DNA is the blueprint that is passed on from the parents to the offspring - is found in a molecule of the cell nuclei. This

molecule, desoxyribonucleic acid, (DNA) is the inherited material responsible for variation. All living organisms contain DNA in their cells.

DNA is the inherited material responsible for variation. Characteristics are passed on from one generation to

another within a species through the genetic code of the parents. This genetic code is called DNA.

Captive breeding programs enable scientists to control populations of species at risk of extinction. Using modern

technology, geneticists and staff from zoos around the world can analyze the genetic code of the species they are trying to save and use it to introduce variation that will help the species survive when the environment changes.

DNA

3 scientists won the 19621962 Nobel Prize in MedicineNobel Prize in Medicine for their work in modeling the structure of DNA.

The scientist who died before she could also be

recognized was …

James Watson Francis Crick Maurice Wilkins Rosalind Franklin

DNA was discovered prior to 1944. All DNA molecules contain exactly the same chemicals, but the way the chemicals combine determines the characteristics of the organism.

To solve the structural questions that DNA posed, four scientistsfour scientists, working in groups of two, revealed that the same chemical building blocks could carry a wide range of instructions needed for diversity.

DNA – The Genetic Code

Watson and Crick modeled the structure of DNA.

The DNA molecule is like a ladder twisted into a spiral. The sides of the ladder are the same in all DNA molecules, but the rungs are what make the variations. Each rung pairs up two of the following chemicals:

guanine (G), cytosine (C), adenine (A) and thiamine (T)

The arrangement of these four chemicals creates the code that the cells are able to interpret.

DNA – The Genetic Code

DNA contains all the instructions, which create the organism's characteristics. The multitude of characteristics for each organism means that there is a lot of DNA in any one cell. This DNA is arranged in the cell in compact packages, called chromosomes. Every human cell contains 46 chromosomes. In order to have a complete human organism, all 46 of the chromosomes must be present. Not all organisms have the same number of chromosomes (Dogs have 78, cats have 38). Every cell of a human contains 23 pairs of chromosomes (dogs 39, cats 19). Not all of the chromosomes from species to species are the same, which accounts for the different characteristics between the species.

DNA - Chromosomes

A single gene is an uninterrupted segment of DNA, which contains the coded instructions for the organism.

Researchers found out that (by working on the fruit fly):

Genes are located in the chromosomes Each chromosome has numerous gene locations Genes come in pairs Both genes in a pair carry DNA instructions for the same thing Specific characteristic genes occupy matching locations on the two chromosomes DNA code may not be exactly the same in both locations Offspring inherit genes from both parents.

The genes exist in an array of possible forms that differ as to their exact DNA sequence. These variations in forms are called alleles. The ultimate combination of the chromosome pair is what makes the variation possible - combining the different variations of different characteristics to create a unique variation.

DNA - Genes

GENETICS

To view a pdf of this image from the Human Genome Project this link is provided ...http://www.genome.gov/11007524

Genetics is the study of heredity - traits inherited from parent to offspring.

Blending TheoryIn ~1850, scientists thought that some fluid substance in the blood of animals or in the sap of plants was the hereditary material. The combination of the parent's characteristics in the offspring was thought to occur by a "blending" of this fluid.

If so, a white dog that mated with a brown dog should produce only tan puppies;

A tall person who had a child with a short person should produce all "medium-size" children, etc...clearly not the case!

Even though people recognized problems with this theory, it was the top theory of the day!

Keep in mind, though, that in the mid-1800s, very little was known about cell structure, let alone the concepts of genes and DNA.

GENETICS

A new theory of how traits were passed on from parents to offspring was put forth

by Gregor Mendel in 1850.

Mendel was an Austrian monk who was interested in plant breeding. He performed careful experiments with the garden pea, Pisum sativum, collected large amounts of data, and in doing so, was able to uncover the basic principles of genetic inheritance that still hold true today!

Mendel's discoveries were not understood by other scientists for over 35 years! It was novel to only allow organisms with the most preferred traits to reproduce. This method is not always successful, but over time ( trial and error ), this practice of controlled breeding has enabled scientists to determine which alleles were responsible for specific traits.

GENETICS

To produce purebred organisms, choose pure bred parents, those parents whose ancestors have produced only the desired characteristic they want (true-breeding).

If a breeder chooses two different 'true-breeds' then a hybrid would be produced.

Cows Bulls

Crossbreeding with purebred bulls for hybrid-vigor, The Bar-N Ranch & Cattle Co. uses Horned Hereford bulls it produces from the registered herd, as well as purebred bulls of other breeds to produce red baldy & brockle faced calves.

GENETICS - Purebred vs Hybrid

Purebred White Bass X Purebred Striped Bass ----> Hybrid Striped Bass

GENETICS - Purebred vs Hybrid

Crossbreeding two different true-breeds will result in all of the offspring having the same characteristic, that is, the dominant trait. Only the DNA instructions for the dominant trait will be carried out. When crossbreeding hybrids, the average results will produce 75% of the offspring with the dominant trait and 25% of the offspring with the recessive trait, because there are only 4 possible combinations. One traits is recessive and therefore the allele is recessive. A recessive trait only appears in the offspring if two recessive alleles are inherited. [Punnitt Squares]

Environmental Factors can also determine how DNA is interpreted and developed. Fetal alcohol syndrome can be a direct result of alcohol consumption during the developing stages of the offspring. The 'normal' DNA is affected by the alcohol and will not develop normally. Taking drugs can also affect the DNA during normal development and defects in the organism can occur. (Thalidomide)

GENETICS - Dominant vs Recessive Traits

Incomplete dominance occurs because the dominant-recessive pattern does not always prevail. When the alleles are neither dominant, nor recessive, an intermediate trait will occur (combining the two traits). In incomplete dominance, the effect of the two alleles is blended.

Offspring Unlike Either Parent - More than one gene location and more than one allele may be responsible for specific traits. As a result, the complex mixing of the possible combinations for that particular trait may account for the variation of traits an offspring has.

In codominance, both alleles are expressed independently and are uniquely recognizable.

GENETICS - Patterns of Inheritance

Stresses of urbanization and habitat intrusion by farming and industry have resulted in a decline in genetic, species and ecosystem diversity. Extinction, population decreases and degradation of ecosystems reduces biodiversity.

BIODIVERSITY - Reduction

Extinction is the disappearance of every individual of a species from the entire planet. It is a natural part of the Earth's history. 99% of species that have ever existed on the Earth are now extinct (many by mass extinction - sudden environmental change, like the Ice Age). Most extinction take place over long periods of time, but the rate of extinctions is rising, and this is reducing the biological diversity of our planet.

Extirpation is a local extinction, or the disappearance of a species from a particular area.

Burrowing Owl

BIODIVERSITY - Extinction and Extirpation

Natural selection is a slow process. Even if there is a lot of variation within a species, sometimes the changes in the environment are so drastic that and so quick, that none of the individuals within a species can survive.

Most extinctions, in the past, were due to: catastrophic events (volcanic eruptions, earthquakes, floods, fire, comets) lack of food (due to overpopulation) disease (spread by insects)

Not all extinctions happened millions of years ago. Diseases and natural events occur all the time and when they do, a species, within a particular area, can be extirpated very quickly.

BIODIVERSITY - Natural Causes of Extinction & Extirpation

Sometimes organisms have adaptations that suit them only to a very narrow set of environmental conditions. This usually occurs in a relatively stable area, where the environment does not change for a very long period of time. This is called overspecialization and it is another cause of extinction. The giant panda is a species that is overspecialized, because it relies on bamboo, making it vulnerable to extinction, when the bamboo is scarce.

In the tropics, where the temperatures are relatively constant and food supply is stable, organisms are also specialists. They efficiently survive in their environment, because they have relatively narrow niches with adaptations directed toward competing for one dependable food source, type of soil or level of light. This specialization allows many different species to coexist in the same area, preventing one species from becoming dominant. The result of this is high diversity with low populations.

A specialist is well adapted to survive in one particular environment. This is considered to be the ‘trap of specialization’, because, as it is able to survive very well in one environment, it is not able to adapt to extreme change and may not survive when this occurs. The cutting down of the rainforests have meant a loss of diversity, because many organisms have been unable to adapt to this change.

BIODIVERSITY - Natural Causes of Extinction & Extirpation

Most extinctions and extirpations today are caused by human activity.

Habitat Destruction - as a result of -

Urbanization Construction Agricultural Development Logging Damming of rivers Pollution Pesticides, Herbicides and Fertilizers

The Grizzly Bear, as a bio-indicator species, helps us to determine the human impact on an ecosystem. This large carnivore’s ability to survive, or disappear, is historically, a sign that human interference in an ecosystem is occurring, or not.

BIODIVERSITY - Human Causes of Extinction & Extirpation

Over-Hunting

This was the major cause of the decline and eventual extirpation of the plains Bison,

as well as,

the extinction of the passenger pigeon.

Over-hunting, over-fishing, and industrial-scale "mining" of natural resources have placed many species in peril.  Over-harvesting of fisheries has reduced the overall diversity of marine life. Over-hunting and illegal trade in endangered species are a prime threat to their survival.

Industrial-scale logging, for wood products and timber, destroys or fragments millions of acres of forests each year, along with the habitat they provide to many uniquely adapted species, such as the endangered red cockaded woodpecker.

Sometimes species are hunted to deliberately extirpate them. The black-tailed prairie dogs were considered a pest in the 1930's and were hunted to reduce their numbers.

BIODIVERSITY - Human Causes of Extinction & Extirpation

Introduction of Non-Native Species When introduced species use the same resources, as the native species, the competition will cause a decline in the numbers of native species, simply because there is less to go around. The introduced species will have no natural predators to limit its population and will, in time, take over from the native species.

Native Prairie Species (Invasive) Non-native Species

BIODIVERSITY - Human Causes of Extinction & Extirpation

Extinctions and extirpations reduce biodiversity.

When an organism disappears locally or globally, many other species are affected.

• There are negative impacts on food webs, symbioses, & species relationships. • Loss of species that support many other species: e.g. legumes, mycorrhizae, kelps. • Loss of functional groups: e.g. photosynthesizers, nitrogen fixers, pollinators. • Reduction of ecosystem efficiency e.g. fewer food webs, pollination or dispersal pathways. • Reduction in community productivity(amount of carbon fixed/unit area/time)

In short, the entire cycle of life is adversely affected.

BIODIVERSITY - Effects of Extinction & Extirpation

Long before Darwin, farmers and breeders were using the idea of selection to cause major changes in the features of their plants and animals over the course of decades. Farmers and breeders allowed only the plants and animals with desirable characteristics to reproduce, causing the evolution of farm stock. This process is called artificial selection because people (instead of nature) select which organisms get to reproduce. The main difference between 'natural' selection and 'artificial' selection is that, humans control the artificial selection process.

Artificial Selection ...The process of selecting and breeding

individuals with desirable traits to produce offspring with the desired traits. Only those individuals, with the desired trait, will be allowed to reproduce.

This selection process also applies to plants, which can be bred to possess desirable traits.

ARTIFICIAL SELECTION

The process of intervention to produce more desirable organisms has been going on for some time. This process takes a long time to see results - usually many generations. Farmers, dog and horse breeders, along with scientists can now speed up the artificial selection process by using 'low-tech' or 'high-tech' technologies, such as;

cloning (made from cells)

artificial insemination (artificially joining the male and female gametes)

in vitro fertilization (male and female gametes are selected and then allowed to fertilize in a controlled setting)

genetic engineering (directly altering the DNA of an organism)

ARTIFICIAL SELECTION - Biotechnology

Preserving global biological diversity is a challenge that is receiving much attention. The 1995 Canadian Biodiversity Strategy was created to preserve biodiversity in Canada. It will be done through the cooperation of many levels of government, along with many groups, agencies and individuals, who are dedicated to preserving our bio-diverse future.

IN-SITU conservation refers to conservation of components of biodiversity within the natural habitat of the organisms being protected.

Protected Areas National Parks, Provincial Parks, game

preserves, natural areas

Restoration Programs for Ecosystems and Species (Governments and Nature Conservancy of Canada programs to purchase land for species habitat renewal, individual landowners giving habitat back - in the form of a naturally protected area, Ducks Unlimited CARE program, Swift Fox - restoration of a species - extirpated from Canada and now recovering)

BIODIVERSITY - Preserving Diversity - IN-SITU

Resource Use Policies (Laws - National Accord for the Protection of Species at Risk - Species at Risk Act - Wildlife Act, 1998)

Controlling the Introduction and Spread of Exotic Species (Information and teaching about the invasiveness of an exotic species is communicated to the public on a regular basis. Penalties and fines, as well as loss of desirable areas for recreational purposes, has improved the perception of the negative effect an exotic species can have on a local ecosystem.)

Purple Loosestrife

(Everywhere)

Zebra Mussels (Great Lakes)

BIODIVERSITY - Preserving Diversity - IN-SITU

EX-SITU conservation refers to conservation of components of biodiversity outside of a natural habitat.

Conservation of Genetic Resources The collection and storage of genetic resources, such as seeds (IPGRI) Zoos (captive breeding programs) Sperm and Egg Banks

Human Genome Project (HGP) was one of the great feats of exploration in history - an

inward voyage of discovery rather than an outward exploration of the planet or the cosmos; an international research effort to sequence and map all of the genes - together known as the genome – of members of our species, Homo sapiens.

Completed in April 2003, the HGP gave us the ability to, for the first time, to read nature's complete genetic blueprint for building a human being.

BIODIVERSITY - Preserving Diversity - EX-SITU