Exam Review – Part 2 Evolution and Diversity You Should Know… 1. What does Evolution mean? 2. What evidence does Darwin have to support his Theory of Evolution? 3. What is an adaptation? 4. Explain 3 ‘selective’ mechanisms by which evolution occurs and 3 non ‘selective mechanisms. – Natural Selection, Artificial Selection and Sexual Selection – Genetic Variation, Genetic Drift and Genetic Bottleneck 4. Be able to compare and contrast the different Modes of Speciation – Reproductive Isolation, Allopatric Speciation and Sympatric Speciation 5. Be able to compare and contrast the different patterns of Evolution – Convergent – Divergent – Co Evolution 6. Know the different types of Diversity – Genetic, Species and Ecosystem 7. Know the Kingdoms of Classification – 6 Kingdoms (Characteristics and Representative Members) 8. Why are Viruses not considered to be alive?? 8. What Phyla make up the Animal Kingdom? – Invertebrates and Vertebrates 9. Know some key characteristics of each of the invertebrate phyla and each of the classes of vertebrates we talked about 10. Be able to discuss how organisms in the Animal Kingdom have become more complex and advanced and how they are adapted to their environments. 11. Know how to use a dichotomous key Principle of Science • Seeks to explain the natural world. • Assumes that this is possible by gathering evidence about it. • Theories are central to scientific thinking: • Theory - Popular meaning: a guess - In science: a well-substantiated explanation of events observed in the natural world Evolution – Darwin defined this term as "descent with modification.” • biological evolution is the process of change by which new species develop from preexisting species over time • Living organisms pass on their traits to their offspring. • Today’s species came about through gradual change. • What drove that change? SURVIVAL/SEX!!!! What Darwin Observed • 1) Homologous and Analogous Features – Homologous features: different functions, but similar structure (flippers, hands, wings) • Analogous features: similar functions, but different structure (wings of birds and bees) • Darwin’s conclusion: organisms with homologous features likely shared a more recent ancestor, while those with analogous features do not! 2) Vestigial Features: • non-functional structures that are homologous to fully functioning structures in closely related species. – Example: whales have pelvic bones that do not attach to legs 3) Artificial Selection – Selecting offspring with desirable traits as breeding stock for succeeding generations – Example: corn with higher oil content – Darwin’s conclusion: if people could alter the appearance and behaviour of species through artificial selection, then the environment could have a similar selective effect on wild species! 4) The Struggle for Survival – Plants and animals produce more offspring than are able to survive – Favourable variations would tend to be preserved, unfavourable ones would be destroyed. INTENSE COMPETITION!!!!! Direct observation of species change Bacteria become resistant to antibiotics Wolves were bred over many generations to become dogs (artificial selection) • and then bred further to create a variety of breeds Mechanisms for Evolution • Natural variation--differences among individuals of a species • Artificial selectionnature provides the variation among different organisms, and humans select those variations they find useful. • Sexual Selection: the process by which a trait that enables an organism to acquire more mates becomes more common. Evolutional Change without Selection • Not all evolutionary changes are the result of selection. • These changes can have a big impact on a species if the population is small. 1. Genetic Drift 2. Genetic Bottleneck 3. Founder Effect Gene Flow • The transfer of alleles from one population to another. Genetic Drift changes to the allele frequency of a population as a result of chance. Bottleneck Effect Genetic diversity is lost as a result of a drastic reduction in population size. Alleles are lost Founder Effect (Type of Genetic Drift) •Individuals of a species (founding population) start a new population somewhere else. Speciation • A new species is formed when two populations of plants or animals accumulate so many genetic changes (mutations, adaptations) that they cannot interbreed and produce fertile offspring. But how did these species evolve??? There are 4 patterns that the evolutionary process may follow… single species evolves into a number of other species. 1. •A Adaptive radiation •A large scaleevolution evolution of a group of species into many 2. Divergent different species. •The evolution of similar traits in 3. Convergent evolution distantly related species. 4. •One species evolves in response to evolution of Coevolution another species. Modes of Speciation… • These processes all include the evolution of distinct features that isolate the new species reproductively and as a result genetically fro the original Individuals arespecies. prevented from breeding together because of behavioural, structural or biochemical traits. 1. Reproductive isolation A new species develops after being geographically separated from the original population. 2. Allopatric Speciation New species are formed when individuals within a larger population become genetically isolated. What Types of Biodiversity are There? • Genetic Diversity – – variety of inherited characteristics within a species – Species vary in their genetic make up • Ecosystem Diversity – – variety of ecosystems on Earth • Species Diversity – – variety of species in an ecosystem. – The greater the number of species in an ecosystem, the greater the species diversity The Six Kingdoms Be able to describe characteristics of each kingdom and give an example of an organism from each. EUKARYOTIC PROKARYOTIC 1. Eubacteria (Bacteria) 4. Fungi 2. Archaebacteria (Archaea) 5. Plantae 3. Protista 6. Animalia Diversity Eukaryotic cells evolved from prokaryotes. - They contained organelles — membrane bound compartments with specialized functions: • Nucleus • Chloroplast Protista • This kingdom contains organisms that display animal-like, plant-like and fungi-like characteristics. Aerobic prokaryotes benefit from food supply. Eukaryotes benefit from energy. Photosynthetic prokaryotes benefit from carbon dioxide inside of eukaryotes and eukaryotes benefit from extra food produced by prokaryotes. http://learn.genetics.utah.edu/content/begin/cells/organelles/ EVERYONE WINS Three Groups of Protists • 1. Plant-Like: contain chlorophyll and may produce food through photosynthesis, … but not always (some have flagella and no cell wall) • 2. Animal-Like (Protozoa): heterotrophs and are very likely to be parasitic • 3. Fungi-Like (slime moulds): some produce spores Vertebrates/ Invertebrates Be able to name the 5 phyla of invertebrates and give an example of each. You should be able to describe the characteristics of each class. Be able to name the 5 classes of vertebrates and give an example of each. You should be able to describe the characteristics of each class. 8Da Invertebrates (5 main phylum) jellyfish arthropods echinoderms Annelida molluscs cnidarians (segmented worms 8Da Phylum Chordata can be split up into 5 classes. amphibians birds fish mammals reptiles Remember the five classes of phylum Chordata. Evolution and Diversity • You should be able to discuss how organisms in the Animal Kingdom have become more complex. • Compare digestive, respiratory and circulatory systems • Explain how certain traits or characteristics may have evolved.