Biodiversity Ch 1 What is Biodiversity and why should we care 1 1 Unity and Diversity of Life bio life diversity variety differences Biodiversity variety of life Individuals may vary in genotype and phenotype genotype set of genes carried by an individual phenotype the expression of a trait in an individual Genes and environment can contribute to diversity within a species Most important discovery of a unifying principle of life was the theory of evolution by natural selection by Charles Darwin and Alfred Wallace in the 19th century There are a vast number of species of life on earth o only named species 50 000 vertebrates 950 000 insects 100 000 bacteria protista 100 00 fungi 300 000 plants 250 000 other invertebrates Currently there are somewhere between 1 5 million and 2 million species named Taxonomists or systematists highly trained specialists required to find and identify new species Species a population or group of populations of organisms that are very similar to one another and share a recent evolutionary history No single definition of a species in biology o 1 Different biological characteristics of different organisms make it hard to use a single characteristic to define a species o 2 Species don t form instantly Wolves and coyotes o 3 Amount of info about species is different in different situations Linnean System of classification species are organized into larger named groups and given several named ranks o Swediesh biologists Linneaus o Every species is given a a name that is known as a bionomial o EX Humans Homo sapiens The first name Homo is the name of the genus to which that species belongs o Genus a small group of very similar closely related species Plulural is genera The highest rank in the Linnean classification is the kingdom o Now most biologists include an even higher level Domain 1 2 Ecology Species diversity and richness Bacteria Archaea and Eukarya Different habitats vary greatly in abundance and diversity of organisms Tundra and the ocean have few different types of plants and animals tropical Species are often defined by the ability to interbreed rainforests and coral reefs have huge numbers of species Closer to the border you are the more species you will encounter Species Richness the number of species occurring in a particular area o Scientists studying communities of species think of diversity as a composite of both the number of species and the evenness of abundance of the different species 1 3 Evolution The Ultimate Source of Diversity The ultimate explanation for biological diversity is evolution Phylogeny shows the diversity of life on earth as a branching tree like structure o Evolution does not simply result in one species replacing another but rather in one species becoming two different species 1 4 Ecological Importance of Biodiversity Ecosystem Services An ecosystem is all the organisms living in a particular area o Includes nonliving environment ie are water soil etc Ecosystem services different species take on different roles in an ecosystem o Species provide oxygen nitrogen for creation of proteins synthesize o Diversity is essential for an ecosystem no one species is capable of biological molecules doing everything 1 7 Genomics Diversity and Molecular Biology Hypothesis test and diversity Biologists compare different form of life to reveal the relationship between form and function comparative method o EX comparing monkeys tree living monkeys have long arms ground monkeys are short therefore long arms are advantageous for tree climbing Genomics the study of the molecular structure of many genes at the same time Genome the entire set of genetic material in a cell o A single cell contains the entire genome of the individual organism Differences in genes are the fundamental basis for diversity o Because they have different Alleles particular version of a gene o Different species have the same games but different versions of them 1 8 Human Impacts on Biodiversity Humans are greatly impacting the world s biodiversity in a bad way o Mass Extinction Events periods in which biodiversity dramatically declined dinosaurs We ve seen 5 in the past 450 million years The last was 65 million years ago the mass extinction of It s estimated that 30 of land bird species may be extinct by 2100 Human caused changes are increasing pop Size of most organisms and increasing chance for extinction o Changes include habitat loss due to human activities movement of invasive species climate change etc Ch 2 Evolution The Source of Biodiversity 2 1 Populational Thinking area Populations groups of individuals of the same species living in the same Mean average Standard deviation measure of variations average distance from the mean Populational views people or animals or bacteria or cities as being parts of populations of similar things o Ex Everyone in Tallahassee is similar in that they live in the same city but differ in a large number of other ways o People think typologically they assign things to categories and expect them to fit into those categories 2 2 Darwin Charles Darwin learned about biodiversity by travelling on the Beagle to South America and the Galapagos Alfred Russel Wallace learned about biodiversity through his travels to the Amazon and SE Asia 2 3 The Theory of Evolution by Natural Selection Biologists before Darwin proposed that species changed over time but Darwin had two major contributions to the concept of evolution o 1 Natural Selection Characteristics that help organisms survive and reproduce in a specific environment will become prevalent in that environment EX Peppered moths during Industrial Revolution o 2 Branching pattern of evolution from a common ancestor all life had a common ancestor great diversity came about through a process of divergence over time species split in two and the two new species evolved to be different from one another phylogeny 2 4 Natural Selection and Evolutionary History are powerful tools for explaining the diversity of life Natural Selection doesn t act on characteristics that don t occur in nature Diversity of life has helped us explain why we and other forms of life grow old o Large animals live longer than small ones 2 5 Where do New Species Come From Natural Selection acts in 3 different ways o 1 Stabilizing Individuals with characteristics close to the mean are most successful and have the most offspring o 2 Directional Individuals at one end of the distribution are more successful and individuals
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