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Biological Diversity A Brief Unit Review Topic 1 – Biological Diversity and Survival • Biological Diversity refers to the number and variety of organisms. • All species rely on and benefit from a high biological diversity on Earth. • Variety refers to differences within or between species. – There is large variety within the domestic dog specie – There is large variety among difference species of the great apes. Topic 1 - Topic 1 – Biological Diversity and Survival • Variety can lead to one species evolving into a new species. This is called speciation. • Some variations help us survive. These then become adaptations: – Structural adaptations – Behaviour adaptations • A Diversity Index compares the diversity of species in an area with the total number of organisms in the same area. If many different kinds of organisms living in an ecosystem would be indicated by a high diversity index. Topic 2 – Habitat and Lifestyle • Species compete for resources when they become scarce: food, water, sunlight, mates, etc. • Often, the better adapted species wins. • Generalists have many adaptations that allow them to occupy broad niches and often reduce competition for resources. • Specialists are only adapted to one type of environment (or they have a narrow niche) and often compete with one another and with other species. Topic 2 – Habitat and Lifestyle • Many different species rely on symbiotic relationships for survival: – Mutualism: and – Parasitism: and – Commensalism: and :l Topic 3 – Passing it On • Reproduction allows us to pass on heritable traits. • Asexual reproduction (aka vegetative growth): – One parent only. – Offspring are identical to the parent. – It’s fast and energy efficient but results in little variation. – Examples: • • • • • Binary fission Asexual spores Budding Layering Meristems Topic 3 – Passing it On • Sexual Reproduction – Two parents pass on their genes – Takes more time/energy but results in variation. – Gamete Zygote Embryo Multicell organism – Flowering and cones plants do it! (see p. 33) – Bacterial Conjugation is considered a form of sexual reproduction because two different bacterial cells are sharing their genes Topic 4 – Wearing Your Genes • Genetic traits can have discreet variation (there are only a few different possibilities – ex: eye colour) or continuous variation (there is a wide range of possibilities – ex: height) • Genetic traits can also be influenced by environmental factors (ex. Diet). • Genes can also mutate • Each of our genes are made up of two alleles (one from mom, one from dad). Topic 4- Wearing Your Genes • Some alleles are dominant over other alleles (recessive). These dominant traits are the ones that are expressed. • Fred Flinstone can roll his tongue (Tt) and Wilma cannot (tt), what is the probability that Pebbles can roll her tongue? Topic 5 – When Plans Change • All of our genes can be found within DNA (deoxyribonucleic acid). • DNA is a double helix (a twisted ladder) – The sides are made of alternating sugars & phosphates – The rungs are made of paired nitrogen bases • Adenine (A) pairs with Tymine (T) • Cytosine (C) pairs with Guanine (G) – A nucleotide = sugar + phosphate + nitrogen base • DNA folds itself into chromosomes Topic 5 – When Plans Change • A human has 23 pairs of chromosomes (46 chromosomes: 23 from mom + 23 from dad). • Mitosis: – Body Cell (46) Doubles (92) 2 body cells (46 each) • Meiosis: – Sex cell (46) Doubles (92) 2 sex cells (46 each) Divides: 4 gametes (23 each) • Reproduction – Sperm (23) + Egg (23) = Zygote (46) Embryo (46) Baby (46) Topic 5 – When Plans Change • Biotechnologies, like genetic engineering, occur when humans change/use genes. • Agriculture benefits from genetic engineering by creating genetically modified foods. – This technology has led to a reduction in biodiversity of naturally occurring fruit and vegetable plants. • Medicine benefits also. We can place the human gene responsible for creating insulin into pigs, bacteria, and plants, and have them produce human insulin for us! Topic 6 – The Best Selection • Artificial Selection is when humans breed organisms with desirable traits. Aka Selective Breeding. • Natural Selection occurs when the most fit species survive, reproduce, and produce offspring that are genetically more fit for survival (survival of the fittest) Topic 6 – The Best Selection • The Theory of Natural Selection: – All organisms produce more offspring that can possibly survive – There is incredible variation within each species. – Some of these variations increase the chances of an organism to survive to reproduce. – Over time, variations that are passed on lead to changes in the genetic characteristics of a species. Topic 7 & 8 – The Sixth Extinction • Some say we are experiencing the 6th major extinction on Earth because biological diversity is decreasing at an alarming rate. • Humans activities are causing these extinctions. Topic 7 & 8 – The Sixth Extinction • We can preserve biological diversity by: – Zoos and Aquariums • Education • Breeding – organisms are exchanged between zoos to prevent interbreeding. – Seed Banks – National Parks – International Treaties • CITES (Convention on International Trade of Endangered Species)