FBS 101 Lec 1-4 Reviewer.docx

***INTRODUCTION TO BIODIVERSITY*** **BIOLOGICAL DIVERSITY** - coined in **1980** by a conservation biologist (**Thomas Lovejoy**) **BIODIVERSITY** (Word) - coined by **W.G. Rosen** in **1985** - first appeared in publication in **1988** by **E.O. Wilson** - **Father of Biodiversity \~...

***INTRODUCTION TO BIODIVERSITY*** **BIOLOGICAL DIVERSITY** - coined in **1980** by a conservation biologist (**Thomas Lovejoy**) **BIODIVERSITY** (Word) - coined by **W.G. Rosen** in **1985** - first appeared in publication in **1988** by **E.O. Wilson** - **Father of Biodiversity \~ Edward Wilson** What is **BIODIVERSITY** - ***variety of life*** in all its forms - ***variation of life*** at all levels of biological organization **GENES → SPECIES → ECOSYSTEMS** and **valuable FUNCTIONS** they perform - essentially a synonym of **'LIFE ON EARTH'** **LEVELS OF BIODIVERSITY** A diagram of different types of organisms Description automatically generated - **Ecosystem Diversity** - Interaction of abiotic and biotic - ***Coarsest scale*** of biodiversity is ***COMMUNITY level diversity***: Groups of species together occupying a locality (an **ECOSYSTEM**) - Communities are shaped by: - Physical environment of an ecosystem - Succession - Niche, carrying capacity - Food webs and guilds - Keystone species -- crucial to the community - Keystone resources (e.g. mangroves, elevational gradients)  - **Species Diversity** A collage of different animals Description automatically generated  A close up of a snake Description automatically generated  - In **2022**, based on **IUCN Redlist**, an estimated **2.16 million** species have been described; estimates for the total number of species existing on earth at present **vary from** **5 million to nearly 100 million** - A conservative working estimate suggests there might be **around 12.5 million** *(most research agree on about 6.8 million species)* - **Genetic Diversity** - The **sum total of the genes** in each organism that inhabit the earth. - **Gene**, as ***a factor of heredity*** is passed on from parent to offspring and determines the physical characteristics that will be expressed in every generation. - **Gene** is a ***storage facility***, a ***repository of genetic information***. - **Phenotype** \> Physical expression of the gene - **Genetic information** \> Physical information - This ***level of diversity can differ by alleles*** (different variants of the same gene, determining phenotypes such as blue or brown eyes) - By **entire genes** (which determine traits, such as the ability to metabolize a particular substance) - Or by **units larger than genes** such as chromosomal structure - This can be ***measured at many different levels***, including population, species, community, and biome. Which level is used depends upon what is being examined and why. Genetic diversity is important at each of these levels. WHY? We can see variation in a population level; among species, community, biomes for their survival and reproduction - Alleles \> describe the alternative form or versions of a gene. - Phenotype describes if alleles are dominant or recessive - Chromosomes - XY male XX Female **GENE POOL:** refers to the combination of all the genes (including alleles) present in a reproducing population or species ***What changes allele frequencies and combinations in populations?*** Selection, mutation, migration, and genetic drift are the mechanisms that effect changes in allele frequencies, and when one or more of these forces are acting, the population violates Hardy-Weinberg assumptions, and evolution occurs. ***How does genetic diversity arise?*** Mutation. New allele frequencies in populations due to selection or genetic drift \> Genetic exchange and recombination \> Heterozygosity **Genetic drift** Heterozygotes - same allele  - **Species** -- ***basic unit of classification for organisms***; include closely related, morphologically similar, interbreeding, individual organisms - refers to the variety of different species or the diversity between species - **Species Diversity** -- Can be assessed at different levels of the classification hierarchy, *viz.* species, genera, families - Variety at different species, or the diversity between species - **Species** - organisms that can make fertile offspring; Asexual reproduction (grafting, etc.,) - Order of Humans - Primates **What is a Species?** - ***Biological Species Concept*** -- **Ernst Mayr**, **1940** - **Species** is a group of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups - Reproductively isolated because of morphological traits - **Basic Unit** of classification **How many Species are there?** - In ***1700's, time of Linnaeus*** -- only about 4,200 plants and animals were described - ***Today*** -- about 2.16 million species (15.4% only) - ***Global estimates*** -- 12 to 14 million species (WCMC 1992, Cox 1997) to as high as 30 million (Hammond 1992, Ehrlich & Wilson 1993) A graph on a white background Description automatically generated  A chart of insects and insects Description automatically generated with medium confidence **Biodiversity** **Crisis** Documenting what is here before it is gone.  A table with text and numbers Description automatically generated with medium confidence ***PHILIPPINE BIODIVERSITY***  These countries have **less than 10%** of the global surface, but **support more than 70%** of the biological diversity on earth. *United States; Mexico; Columbia; Venezuela; Ecuador; Peru; Brazil; Democratic Republic of Congo; South Africa; Madagascar; India; China; Malaysia; Philippines; Indonesia; Papua New Guinea; Australia* **MEGADIVERSITY COUNTRIES**: 17 nations collectively claim within their horders more than two-thirds of the Earth's biological resources. These countries are also home to a major portion of the planet's cultural diversity. In terms of plant and animal species at risk, as much as 80% of the world\'s most endangered biodiversity is found within the megadiversity countries **PHILIPPINE FAUNAL DIVERSITY** +-----------------------+-----------------------+-----------------------+ | Description | Number of sp. | Additional Info | +=======================+=======================+=======================+ | *Amphibians (Frogs, | 111 | 82 found only in the | | Toads, Salamanders, | | Philippines | | Cecillian)* | | | +-----------------------+-----------------------+-----------------------+ | *Reptiles* | 20 species of snakes | About 270 are found | | | are venomous (7 | in the Philippines | | | endemic in the | (lizards, turtle, | | | Philippines) | crocodiles, and | | | | snakes) | | | | | | | | 208 (82%) are endemic | | | | to the Philippines | +-----------------------+-----------------------+-----------------------+ | *Aves/Birds* | 576 including | 192 occur only in the | | | migratory; Around 100 | Philippines | | *(Most abundant in | are migratory | | | terms of species | | | | richness)* | | | +-----------------------+-----------------------+-----------------------+ | *Mammals* | 179 land | 52 threatened | | | | species; 1 possible | | | | extinct; 111 species | | | | are found only in the | | | | Philippines | +-----------------------+-----------------------+-----------------------+ | *Insects* | \> 20,940; including | 69.8% are endemic ≥ | | | anthropoids 7,000 | 14,616 | +-----------------------+-----------------------+-----------------------+ | *Corals* | | 12 species are | | | | endemic to the | | | | Philippines | | | | Indonesia; | | | | | | | | 20 species recently | | | | described in the | | | | Calamianes; 1 new | | | | species of Leptoseris | | | | in the Kalayaan Is. | +-----------------------+-----------------------+-----------------------+ | *Freshwater, land and | 22,000 | | | marine molluscs* | | | +-----------------------+-----------------------+-----------------------+ | *Reef fish* | 2,500; 915 sp. Reef | | | | and reef-associated | | | | fish | | +-----------------------+-----------------------+-----------------------+  **Freshwater Crocodile (**Philippine Crocodile) -- Most Critically Endangered among Crocodiles **2 Species of Crocodile** A blue background with yellow text Description automatically generated  A blue background with black text and numbers Description automatically generated  **PLANTS**: estimated 15,000 species, 50% are endemics; 70 -- 80% Flowering plants 984 Threatened species **BIODIVERSITY HOTSPOT** - Philippine species face one of the highest level of endangerment - **\>93% of forest cover** has been **lost** in the last 500 years ago - **697 threatened species** (2010 IUCN Red List) - Megadiversity and biodiversity hotspot country - **2nd hottest spot** ***PATTERNS AND THEORIES OF SPECIES DIVERSITY*** **QUESTIONS** 1. What are the reasons the tropics have more species than temperate and polar regions? 2. What does it mean that biodiversity patterns are scale dependent? 3. How do we estimate the total number of worlds species? 4. What are the reasons species richness goes up when you sample a larger area? **How many species are there?** - How do we know? - Take what we do know, project it to include things we don't - Example 1: species-area curves - Example 2: body size - Example 3: sub-sampling - Estimates range from 5 to 100 million species (1.7 million described) - New species being discovered - Strong biases in counts - 1980: study of 19 trees in a tropical rainforest - 1200 species of beetles - 80% previously undescribed - Likely 6 to 9 million species of arthropods - 1 sq m tropical forest: - 200,000 mites, 32 million nematodes, 90 million bacteria - \# of species? - Oceans: very poorly studied, especially deep sea - Estimated 1 million undescribed species from deep sea **Scale dependence** ***Biodiversity patterns are sensitive to SCALE***. - Just as what you see through a telescope depends on the magnification and field of view. **Three basic reasons species richness increases with area:** 1. ***Habitat diversity*** goes up (a greater range of environments are sampled, potentially including a greater array of niches) 2. ***Population sizes increase***, leading to a lower extinction rate (from island biogeography) 3. Some ***species require large areas*** because they have large ranges or habitat requirements (e.g., large predators) **Patterns of species richness** Broad Scale Fine Scale ------------- -------------- Latitude Productivity Climate Disturbance Elevation A map of the world Description automatically generated  A graph with dots on it Description automatically generated **Latitudinal Gradient** - Groups that provide evidence for a latitudinal gradient in diversity: Birds Marine Gastropods ------------------- ------------------- Mammals Marine Bivalves Freshwater Fishes Marine Fishes Trees Corals Epiphytes Insects - Many have argued that this pattern is universally true for all large taxonomic groups Many small taxonomic groups, e.g. pine trees, don'tshow the expected pattern despite the fact that trees overall show the latitudinal gradient  **Latitudinal Gradient** - Other taxonomic groups also dont show the expected latitudinal gradient in diversity, but in each case the expected pattern is seen at a higher taxonomic level: - Penguins (family) vs. Birds (Class) - Seals (family) vs. Mammals (Class) - Ichneumonidae (family) vs. Insects (Class) - Threvidae (family) vs. Insects (Class) **Explanation Over Latitudinal Gradient of Diversity** 1. ***Historical Perturbations*** -- places that have been disturbed (e.g. by glaciation) may have fewer species because of A. Differential rates of extinction B. Inadequate time for species to recolonize 2. ***Differential rates of evolution*** -- places with more resources or higher temperature may have faster rates of evolution 3. ***Climatic Stability*** -- stable climate may promote specialization (and speciation) and reduce extinctions 4. ***Harshness*** -- harsh conditions may limit species numbers 5. ***Interspecific interactions*** -- biotic interactions may promote specialization and coexistence and are more intense in the tropics 6. ***Habitat Heterogeneity*** -- diverse habitat structure may permit finer subdivision of resources and greater specialization 7. ***Productivity/Energy*** -- greater available energy may allow for greater numbers of species to coexist A group of graphs showing different types of weather Description automatically generated with medium confidence A graph of different types of evapotranspiration Description automatically generated  ***BIOGEOGRAPHIC THEORY AND ZONES*** Cartoon penguins in the snow Description automatically generated **BIOGEOGRAPHY** - ***geographic patterns of species distribution*** & the ***processes*** that result in such patterns. - ***distribution of life forms***, past & present, & the ***causes*** of such distributions. - describes the ***distributions of living & fossil species*** of plants & animals across the Earth\'s surface as ***consequences of ecological & evolutionary processes***. **Some Questions Related to Biogeography** - Why did some/several organisms become extinct? - What factors contribute to the occurrence of unique species in some geographical units? - How did speciation and species gradients occur? - What environmental factors influence distribution of organisms? - Why there are a certain number of species in a particular geographic region? **Biogeography is a synthetic science.** - Geography - Evolutionary Biology - Soil science - Geology - Climatology - Ecology - Evolution - Paleontology - Molecular Systematics **Some Fundamentals in Biogeography** - ***Evolution*** (change in genetic composition of a population due to adaptation & counteradaptation) - ***Extinction*** (disappearance of a species) - ***Dispersal*** (movement of populations away from their point of origin, related to migration) - ***Range and distribution*** - ***Endemic areas*** - ***Species variations*** Based on relatively complete compilations of species within well-studied groups, such as birds and mammals, biogeographers identified ***six different biogeographic realms or zones*** within which species tend to be closely related and between which turnovers in major groups of species are observed. **Biographic Realms or Zones** +-----------------------+-----------------------+-----------------------+ | **Realm** | **Continental Areas | **Examples of | | | included** | Distinctive or | | | | Endemic Taxa** | +=======================+=======================+=======================+ | **Paleactic** | Temperate Eurasia and | Hynobiid/Asiatic | | | northern Africa | | | | | salamanders | +-----------------------+-----------------------+-----------------------+ | **Oriental** | Tropical Asia | Lower apes(macaque) | +-----------------------+-----------------------+-----------------------+ | **Ethiopian** | Sub-Saharan Africa | Great apes (Gorilla) | +-----------------------+-----------------------+-----------------------+ | **Australian** | Australia, New | Marsupials | | | Guinea, | | | | | | | | and New Zealand | | +-----------------------+-----------------------+-----------------------+ | **Nearctic** | Temperate North | Pronghorn antelope, | | | | | | | America | ambystomatid/mole | | | | | | | | salamanders | +-----------------------+-----------------------+-----------------------+ | **Neotropic** | Subtropical Central | Hummingbirds, | | | | | | | America and South | antbirds, marmosets | | | | | | | America | | +-----------------------+-----------------------+-----------------------+ **Biogeographic Realms or Zones**  **Major Terrestrial Biomes** A map of the world with different colors Description automatically generated  **Biome distribution is closely associated with climate** Factors regulating or limiting the distribution of organisms -- **BARRIERS** 1\) ***Physical barriers*** such as land (e.g. islands & mountain and water 2\) ***Climatic barriers*** such T^0^, moisture, sunlight, etc 3\) ***Biologic barriers*** such as absence of food, presence of competitors, predators, or diseases - The patterns of species distribution level can usually be explained through a combination of historical factors - Speciation - Extinction - Continental drift - Glaciation (and associated variations in sea level, river routes, and so on) - River or stream capture, in combination with the area and isolation of landmasses (geographic constraints) - Available energy supplies A map of the world Description automatically generated  **Equilibrium Theory of Island Biogeography** (by ***Robert MacArthur*** and ***Edward O. Wilson***, **1967**) - the **number of species** living on an island is a function of **extinction** and **immigration** rates on the island - **species diversity** of an area is the result of an **equilibrium** between **colonization and extinction**. - the number of species found on an island (the **equilibrium number**) is determined by two factors, the **effect of distance from the mainland** & the **effect of island size**, that would affect the rate of **extinction** on the islands & the level of **immigration**. - Implies a constant **turnover** in species, i.e., continual changes in species composition. **Species diversity** depends on the *balance between immigration rate and the extinction rate of species* or populations on these islands  The *success of dispersal and colonization* is **directly proportional** to the *size of the island*  The probability of species reaching and colonizing an island (or patch) is inversely proportional to the distance between the island (or patch) and the mainland that is the source of immigrants/colonizers **Factors that Influence Island Communities** - ***Degree of isolation*** (distance to nearest neighbor, and mainland) - ***Length of isolation*** (time) - ***Size of island*** (larger area usually facilitates greater diversity) - ***Climate*** (tropical versus arctic, humid versus arid, etc.) - ***Location relative to ocean currents*** (influences nutrient, fish, bird, and seed flow patterns) - ***Initial plant and animal composition if previously attached to a larger land mass*** (e.g., marsupials, primates, etc.) - The ***species composition of earliest arrivals*** (if always isolated) - ***Serendipity*** (the impacts of chance arrivals) - ***Human activity*** **Applications/Implications of Island Biogeography** - Habitat fragmentation (***insularization***) -- there could be "***ecosystem decay***" or "***faunal collapse***" (there is species loss as new equilibrium number is achieved, esp. For larger species); creation of metapopulations - Development of ***habitat corridors*** as a conservation tool to increase connectivity between habitat islands. Habitat corridors can increase the movement of species between parks and reserves. - Green bridges as wildlife corridor - Wildlife corridors connecting critical habitats A map of a farm land Description automatically generated  A diagram of different types of animals Description automatically generated **Implications of Island Biogeography** - Conservation planning gives priority on one large reserve that could hold more species; - larger reserves should be the norm in **reserve design** - **Speciation** -- allopatric and sympatric - ***allopatric*** -- populations of the same species become geographically isolated preventing genetic interchange - ***sympatric*** -- new species evolve from a single ancestral species while inhabiting the same geographic region **Effects of fragmentation** 1\. ***Reduction in total area*** (**sampling effect problems**) - loss of original habitat diversity - exclusion of some species by chance - reduction in population size of species (small population problems) - Species that is adapted well to particular site conditions - Species with a large facilitative effect on other members of the community (***dominant species***) 2\. ***Formation of disjunct areas*** (**insularization effect**) - decrease in dispersal and immigration - Isolation of population - faunal collapse or relaxation (habitat patch remain but no more immigration) - Vulnerability during dispersal to other patches 3\. ***Increase in* edge habitat** - further reduction in effective habitat area (edge habitat is poor) - increased predation (associated with edge or adjacent habitat)  - invasion of exotics (edge habitat is altered enough to allow invasive species to establish themselves) - disease (from adjacent areas) - Change in microclimate **What species are most affected by fragmentation?** 1\. **Area sensitive** (e.g., carnivore with large area, low prey density) 2\. **Isolation sensitive** (e.g., reproductive life history requires a dispersal phase through a certain kind of habitat) 3\. **Edge sensitive** 4\. **Rare species** (because of sampling effect - reduction in total habitat and or reduced population size) 5\. **Specialists or highly coevolved species** (e.g., some species of birds require large tracts of old growth. Must maintain both populations)