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Science 9- Biology Unit
Transcript of Science 9- Biology Unit
and Survival The entire collection of living organisms, each with their own unique characteristics, makes up the Earth’s biodiversity. Biological diversity refers to the number and variety of species and ecosystems on the Earth. A Wealth of Diversity Interdependence of many different species stresses the need to protect what species we currently have on the Earth A species is a particular group of organisms that have the same structure and can reproduce with each other. 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. The most successful life form seems to be the insect. The main components of biodiversity include: – the different types of living communities and the environments, such as marshes, lakes, streams and forests, Ecosystem diversity – occurs within populations of organisms living within a particular ecosystem Community diversity – occurs within individual organisms of the same species Species diversity – occurs within organisms at a cellular level, as it describes the variety of
genetic material in all living things. Genetic diversity – Plant and animal species are not distributed evenly throughout the various eco-regions of the world. Species Distribution Most of the different species of plants and animals can be found in tropical regions and, more specifically, in the rainforests. As you move closer to the poles of the
Earth, there is less biological diversity. Variations for Survival Every organism needs to adapt in order to survive in its environment. There are two types of adaptations.
Physical features of an organism are structural adaptations, whereas, actions are
behavioral adaptations. Measuring Biological Diversity 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. Read the yellow...
that's the english part... 7 min on loss of Biodiversity 9 mins 3 mins loud video- turn down
2 mins on strange species read pages 6 and 7 read pages 12-13 Topic 2-
Habitat and Lifestyle The Niche: What Makes an Organism Special? A niche is the role an organism has within a particular ecosystem. What it eats What eats it Its habitat Nesting site, range and habits What effect it has on the environment Variation and Competition When basic need resources (food, water, sunlight, habitat) are not plentiful, different species
compete for the resource. This competition is often not fair – because one species may have an advantage over other species. VARIATIONS advantages could be Status advantages could be SPEED advantages could be SIZE or how tall you are... 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. In the tropics, where the temperatures are relatively constant and food supply is stable, organisms are specialists. The result of this is high
diversity with low populations. Symbiosis There are different types of symbiotic relationships: – in which one of the participating members benefits, but the other does not, and there is no harm done to that organism. Commensalism (a bird using a tree to build its nest in) (barnacles on a whale) – both organisms benefit from the relationship. Mutualism – 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. Parasitism 10 mins symbiosis- good film 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. Interspecies competition Topic 3-
Passing It On Characteristics are passed on from generation to generation through the reproductive process. Some characteristics, or traits, are inherited through genetic material. reproductive strategies Asexual Reproduction Asexual reproduction involves only one parent who passes on the genetic information to their offspring. This sharing of genetic information makes the offspring identical to the parent. Binary Fission only single-celled organisms reproduce in this way. The cell duplicates its contents and then splits into two cells with each one being identical. (bacteria, amoeba, algae) Spore Production spores are similar to seeds, but are produced by the division of cells on the parent One parent may produce many spores, each of which will grow into a new individual, identical to its parent. (fungi, green algae, moulds, ferns) Budding the parent organism produces a bud (a smaller version of itself), which eventually detaches itself from the parent (hydra, yeast, coral, sea sponge). Asexual Reproduction in Plants At a certain time these cells will specialize into cells that make up roots, stems and leaves. Clones can be made from cuttings of a plant, because the cells can specialize to reproduce the different parts needed to make a new plant. Sexual Reproduction Sexual reproduction usually involves two individual organisms. The offspring that are produced from this union have a mix of characteristics, half from one parent and the other half from the other parent. 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. Sexual Reproduction in Plants Sexual reproduction in plants involves gametes as well, male gametes and female gametes joining, during fertilization, to produce a zygote and then an embryo. Sexual Reproduction in Animals Sexual reproduction in animals involves gametes. The male gametes are called sperm cells, and the female gametes are called egg cells During mating, the sperm cell and the egg cell unite to form a fertilized combination of cells called a zygote. 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. Topic 4- Wearing Your Genes Variation is one of the most critical aspects of species survival. because it may be a behavioral tendency or a genetic modification that enables some individuals within a species to survive! Two Kinds of Inherited Variation Inherited (heritable) characteristics are those traits which are passed on to offspring directly from their parents. Continuous variations;
are differences in characteristics that have a range of possible variations, such as height,
etc. Discrete variations;
are differences in characteristics that have a definite form, with a limited number of possibilities. Examples include:
tongue rolling ability,
etc. Dominant or Recessive? Traits are passed on from parents to offspring during sexual reproduction. When they are mixed, a dominant trait will show up in the offspring. eye coloring brown eyes grey, green, hazel, blue eyes
vision farsightedness Normal vision
normal vision nearsightedness;
hair dark hair blonde, light, red hair
non-red hair red hair
curly hair straight hair
widow's peak normal hairline
full head of hair baldness*
facial features dimples no dimples
unattached earlobes attached earlobes
freckles no freckles
broad lips thin lips Here is some of the many examples of Dominat or Recessive Traits.
Which ones do you have from your parents? Nature Versus Nature 1:30 mins 2:30 mins 2:00 mins Changing Our Genetic Information Factors in the environment, or random events can change genetic information contained in DNA. Mutagens, such as X-rays, ultraviolet rays, cosmic rays and some chemicals can cause mutations to occur –
some that have little visible effects and some that have dramatic effects. Some mutations can cause cancer, which promote rapid cell division and impair full normal cell development. If mutations occur in the DNA of reproductive cells, the changes can be passed on from the parent to the offspring, increasing the variation within a species. Remember the Thalidomide Issue, where the pregnant mother passes her bioaccumulation onto her children... Topic 5 -
When Plans Change DNA: The Secret of Life The blueprint that is passed on from the parents to the offspring is found in a molecule of the cell nuclei. All living organisms contain DNA in their cells. DNA was discovered prior to 1944,
by Swedish chemist Johann Miescher (1886). 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. The Structure of DNA All DNA molecules contain exactly the same chemicals, but the way the chemicals combine determines the characteristics of the organism. Each rung pairs up two of the following chemicals:
-adenine (A) and
-thiamine (T). The arrangement of these four chemicals creates the code that the cells are able to interpret. This is the genetic code of the organism. This genetic code is a unique sequence in each individual that provides the blueprint for each individual organism. The Dance of the Chromosomes All human cells contain 46 chromosomes. Not all organisms have the same number of chromosomes (Dogs have 78, cats have 38) 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. how DNA works 1:38 mins how DNA works part 1 What are SNPs? where do Genes come from? Textbook
p.57 Wrap up
questions Topic 6 -
The Best Selection Long before the science of genetics started, people tried to reproduce organisms with only the most preferred traits, by allowing only those organisms with the desirable traits to reproduce. Accounting for Biological Diversity The specimens and observations made by Charles Darwin about the diversity of life on the Galapagos Islands is detailed in his most famous book, Origin of the Species by Means of Natural Selection. The Theory of Natural Selection The diversity of life in the Galapagos Islands helped Darwin explain his theory of natural selection. It can be summed up in four statements: 1. All organisms produce more offspring than can possibly survive.
2. There is incredible variation within each species.
3. Some of the variations increase the chances of an organism surviving to reproduce.
4. Over time, variations passed on through offspring lead to changes in the genetic characteristics of a species. Natural selection happens when factors in the environment determines, or ‘selects’ which individuals, within a species, will be able to survive. Artificial Selection in Agriculture (and Ranching) 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. Topic 7 -
The Sixth Extinction Natural extinction can occur as a result of: • catastrophic events (volcanic eruptions, earthquakes, floods, fire)
• lack of food (due to overpopulation)
• disease can you name 3?... Diseases and natural events occur all the time and when they do, a species, within a particular area, can be extirpated very quickly. overspecialization 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. Extinction is the disappearance of every individual of a species from the entire planet. It is a natural part of the Earth's history. loud vid-
extinct creatures. 1:30 min 6 degrees Extirpation is a local extinction, or the disappearance of a species from a particular area. what do you think causes Extirpation? Disappearing Habitats
As a bioindicator species, the Grizzly Bear 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. May 2008 news When introduced species use the same resources, as native species, competition will cause a decline in the numbers of native species, simply because there is less to go around. lots of diferent trees in just one forest! Variations in the same species!! Animals living together in a community They look similar, but there are small differences.... Differences that you can't always 'see', but make up very important differences! Allergic to peanuts left handed Diabetic thinks she's a princess Please Read Page 37-38
in your text book
and start the activity on page 38 Please Read Page 40 Please Read page 42
(Even the 'Did you knows' on the side of the page) Read pages 53-54
Write out in your own words what Genetic engineering is... search in you tube
Cosmos: "Heike Crabs" how do you think this crab got the 'face' look on his shell? read page 58- 59 read pages 60- 61 read page 64 read page 68, answer the 'analyze' questions
Topic 8 -
Pains and Gain The Role of Zoos in Preserving Biodiversity Zoos were not originally started to preserve diversity. They were exotic collections for private collectors. They didn’t become public until the early 1800’s – in London. Today there are thousands around the world and we have one of the finest - right here in Alberta. please read p 73 Preserving the Biodiversity of Plants please read p 75 and wire out what a 'Seed Bank' is in your own words. Are seed banks a good idea? Explain your choice. well... is this guy crazy? or is having a seed bank with all the plant seeds locked away a smart thing?
A Global Effort
The preservation of biological diversity depends on local efforts and global efforts. Global Treaties: 1975 Convention on International Trade of Endangered Species (CITES) is aimed at preventing endangered plants and animals from being imported or exported.
It is illegal to buy or sell animals or animal parts identified for protection by CITES. please read page 76