Lecture 1: Biodiversity PDF

LECTURE 1 BIODIVERSITY WHAT IS BIODIVERSITY The variety of life Biological diversity’ means the variability among living organisms from all sources including, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity withi...

LECTURE 1 BIODIVERSITY WHAT IS BIODIVERSITY The variety of life Biological diversity’ means the variability among living organisms from all sources including, terrestrial, marine and other aquatic ecosystems and the ecological complexes of which they are part; this includes diversity within species, between species and of ecosystems Convention on Biological Diversity HOW MUCH BIODIVERSITY IS THERE? Y E Y - z ~ - L Y L  anaut -india direa ~ of DNAof f GENETIC DIVERSITY ~ genne is ↑ - copy I house one Genetic diversity encompasses the components of the genetic coding that structures organisms (nucleotides, genes, chromosomes) and variation in the genetic make-up between individuals within a population and between populations. genetic diversity is - The most basic measure of - genome size—the amount of bP DNA (Deoxyribonucleic acid) in one copy of a species’ chromosomes (also called the C-value). - - > one copy of speci Genome Humans have a genome size of 3.5 pg (3.4 billion base pairs). size  Within a species, genetic diversity is commonly measured in terms of allelic diversity (average number of alleles per locus), gene diversity D (heterozygosity across loci), or nucleotide differences. ↑ Large populations tend to have more genetic diversity - - populations more than those that wildly fluctuate. than small ones,- more stable must Such variation can have a variety of population-level influences, including on - productivity/biomass, fitness components, behavior, and responses to - - - - disturbance, as well as influences on species diversity and ecosystem processes - tell per t attel fregency diver sit locus 2. gene diversity 3. motetide difference  PROBLEMS WITH THE GENETIC DIVERSITY LEVEL Should one preserve one population or many, and how many, populations, given that each population is usually genetically distinct from the other one? Every individual is genetically unique, except for identical twins. Thus, all individuals vary genetically Grene Banks So, how many can be preserved!!?? a test tubes Gene banks can resolve the problems by preserving the genotype of many individuals in test tubes...but would that make removing populations and habitats an acceptable practice!!?? - X  King Dom Gewend population prepent t - ORGANISMAL DIVERSITY Organismal diversity encompasses the full taxonomic hierarchy and its components, from individuals upwards to populations, subspecies and species, genera, families, phyla, and beyond to kingdoms and domains. Unfortunately, when one speaks of biodiversity, this is the main level of focus, making people ignore the other two levels!!! little is known about how many individual organisms there are at any one time, although this is arguably an important measure of the quantity and variety of life Currently, about 2 million species have been classified by scientists  Ca Individual organisms can be grouped into relatively independent populations of a species on the basis of limited gene flow and some level of genetic differentiation (as well as on ecological criteria). The population is a particularly important element of biodiversity. First, it provides an important link between the different groups of elements of biodiversity (Table 2.1). Second, it is the scale at which it is perhaps most sensible to consider linkages between biodiversity and the provision of ecosystem services (supporting services—e.g. nutrient cycling, soil formation, primary production; provisioning services—e.g. food, freshwater, timber and fiber, fuel; regulating services—e.g. climate regulation, flood regulation, disease regulation, water purification; cultural services—e.g. aesthetic, spiritual, educational, recreational See next lecture!  How many different species of organisms there might be? Greatest uncertainty continues to surround the richness of prokaryotes, and in consequence they are often ignored in global totals of species numbers. Global prokaryote diversity has been argued to comprise possibly millions of species Numbers of eukaryotic species are still poorly understood. New species are being described at a rate of about 36 species on the average day.  PROBLEMS WITH THE ORGANISMAL DIVERSITY LEVEL ignore genetic diversity It is difficult to discover and document all species...too laborious, underfunded, requires thousands of experts Ignores genetic diversity among populations Sometimes, parents and offspring need different habitats to survive, so would this Y make them two different species that require two different habitats? Think of the butterflies and the caterpillars! Some would argue that species exist in the zoo, so there is no need to preserve X their habitats!! abictiv Bioti& ECOLOGICAL DIVERSITY e - - - ~ The third group of elements of biodiversity encompasses the scales of ecological differences from populations, through habitats, to ecosystems, ecoregions, provinces, and on up to biomes and biogeographic realms This level is hard to define and gets least attention from conservationists, since it consists of biotic and abiotic components and biodiversity is defined as variety of life—i.e. biotic only However, careful considerations points that biotic can’t exist without preserving the abiotic PROBLEMS WITH THE ECOSYSTEM DIVERSITY LEVEL What is an ecosystem...it can be a petri dish in the lab or it can be a whole forest!! Most ecosystem change with time-succession. So, are they worth preserving? Sometimes an ecosystem is embedded within another, like a lake in a forest. So, are those two different ecosystems or one!?  IMPORTANT NOTE The level at which you define biodiversity will have strong impact on conservation efforts. For example, if you say to a law maker, I need to preserve this species, they will say okay, we’ll breed it in the zoo. This way, you lose the habitat and the genetic diversity of other populations. You can ask to preserve few populations, but then they will wipe out the rest of the species and the habitats they live in. You can ask to preserve the ecosystem, but then they will say they will get rid of the species in that ecosystem You can say you want to preserve, the desert, for example. They will say fine; we’ll leave Al Ain desert intact, but develop all other deserts in Abu Dhabi!! BE SMART IN FORMULATING YOUR PROJECT AND GOALS!!!  Important Definitions Population: 11 - - ~ & - - A group of individuals of a given species that live in a specific geographic area at a given &time. ~ ~ - % Community: & 3 E of organisms of different species. A community includes populations Ecosystem: -- Ecosystem includes a community of living organisms (biotic) interacting with the environment (abiotic). Biome: A biome, in simple terms, is a set of ecosystems sharing similar characteristics with their abiotic factors adapted to their environments. Biosphere: A biosphere is the sum of all the ecosystems established on planet Earth. It is the living (and decaying) component of the earth system.  HOW HAS BIODIVERSITY CHANGED THROUGH TIME? Based on fossils, chemical evidence, and extrapolation from molecular clocks, the first appearance and relationships of the major domains of life are indicated against a 4.6-billion-year time scale.  WHY ARE WE STUDYING CONSERVATION BIOLOGY Conservation biology is a new discipline that emerged in the late 1970s and early 1980s as biologists began to react to the swift rise in human-caused species extinctions. The rate of extinction is estimated to be from 40-250 spp. /day worldwide, while the human population swells by 260,000/day. Michael Soule, - the founder of this field, terms it a "crisis discipline" because we may have to make decisions quickly and without full scientific confidence, likening our task to triage in an emergency room. So, it is humans are the villains in this story Michaul Soute Summary Biodiversity is the variety of life in all of its many manifestations. This variety can usefully be thought of in terms of three hierarchical sets of elements, which capture different facets: genetic diversity, organismal diversity, and ecological diversity. Pragmatically, and rather restrictively, biodiversity tends in the main to be measured in terms of number measures of organismal diversity, and especially species richness. Biodiversity has been present for much of the history of the Earth, but the levels have ↳ changed dramatically and have proven challenging to document reliably. riche Species organis met diversity ->