Biodiversity, Human Impact, and Conservation

Lecture 1: Biodiversity Biodiversity is the variation of lifeforms within a given ecosystem. Genetic Diversity: individual genetic variation within a population and the genetic variation between populations Species Diversity: the variety of species in an ecosystem Ecosystem Diversity: the variety of the biosphere’s ecosystems An Ecosystem is the sum of all the organisms in a given area as well as the abiotic factors with which they interact. A Biodiversity Hotspot is a relatively small area with an exceptional concentration of endemic species and a large number of endangered or threatened species. Endemic Species: A species only found in one region or part of the world Ecology is the study of the interactions between organisms and the environment. Definitions from: Campbell, Neil, and Jane Reece. Biology. Seventh. San Francisco: Pearson Education Inc., 2005. 1078-1229. Print. 

Understanding Ecology Studying ecology will reveal the richness of the biosphere. Ecological interactions can determine both the distribution of organisms and their abundance. With this understanding, one will be able to help conserve and sustain biodiversity.

Determining Species Distribution and Abundance 1) Environmental Factors Temperature Seasonality 2)Amount and Variability of Precipitation Dispersal contributes to this global distribution of species. Above: Biogeographic realms indicating distribution patterns due to continental drift and topographic land barriers

Flowchart of Factors Limiting Geographic Distribution Understanding the Flow Chart: Behavior Limits: refer to habitat selection Biotic Factors: mainly refer to predation and the presence or absence of food resources but may also include parasitism, disease, or competition Abiotic Factors: include temperature, water, sunlight, wind, and climate conditions Flowchart replicated from Campbell, Neil, and Jane Reece. Biology. Seventh. San Francisco: Pearson Education Inc., 2005. 1078-1229. Print. 

Climate mainly determines the Distribution and Structure of Ecosystems Temperature and precipitation in addition with physical geographic features determine the structure of terrestrial Biomes

Introduction to The Tropics Tropics are the location of many biodiversity hotspots because of their unique structure and history that resulted in species diversity. 50% of the worlds species are found in the tropical rainforests.

Tropical Rainforests as Hotspots There are 3 main regions of tropical rainforests 1)The Americas 2)Africa 3)Australasia The Conservation International has established global hotspots. An interactive map can be found here: http://www.biodiversityhotspots.org/Pages/default.aspx

Biodiversity is not limited to animal species but plant species as well. Tropical Rainforests are comprised of 100-300+ species of trees pre hectare. And few trees are common, while many are rare The Tropical Rainforests have increased faunal diversity and density

Effects of Faunal Groups Direct contribution to species richness Indirect effects on plant and animal diversity Contribute substantially to total biodiversity of Rainforests Contribute irreplaceable services such as seed dispersal, seed predation, and seed pollination In summary, the faunal composition effects how ecosystems function

Like faunal groups effect Tropical Rainforests, marine ecosystems are affected by Coral Reefs

Coral Reefs are among the most Diverse Ecosystem Coral Reefs are the richest in species of any marine environment Coral Reefs are the keystone species of the marine environment Note a keystone species is a species whose presence has a disproportionate effect on the ecosystem and contributes to the diversity of the ecosystem. Without this species, there is a direct correlation to extinction in other species

Coral Reefs, The Hotspot Coral Reefs only comprise 0.2% of the Earth’s Ocean Surface and they almost exclusively occur within the Tropics Abundance and Distribution is strongly affected by temperature The Current Distribution of Coral Reefs is shown to the right. -Caribbean -Coast of Central America -Indo-Pacific Waters -East Coast of Australia

Biodiversity is Effected by Several Biotic and Abiotic Factors, but the Greatest Threat to Biodiversity is Human Impact