Conservation Genetics. Scope of Ecology. Density and Distribution of Populations. Ecology

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1 Conservation Genetics Scope of Ecology Ecology The study of the interactions of organisms with other organisms, and The physical environment Habitat - Place where an organism lives Population - All the individuals of a species within a particular space Community Specified populations interacting with each other Ecosystem - Community interacting with environment 2 Density and Distribution of Populations Population Density - Number of individuals per unit area or volume Population Distribution - Pattern of dispersal of individuals within a space of interest Ecologists analyze what causes the spatial and temporal patchiness of organisms Limiting factors are factors that predominantly determine whether a species lives in a habitat 3

2 Carrying Capacity Carrying Capacity The maximum number of individuals of a species the environment can continuously support The closer the population to the carrying capacity, the greater the environmental resistance 4 Human Population Growth Human population has an exponential growth pattern Doubling time currently estimated at 53 years Population Size Billion Billion Billion Billion 5 Country Development More-Developed Countries (MDCs) Slow population growth High standard of living Completed Demographic Transition North America and Europe Less-Developed Countries (LDCs) Rapid population growth Low standard of living Latin America Africa and Asia 6

3 Environmental Impact Environmental impact of a population is measured in terms of: Population size Resource consumption per capita Resultant pollution 7 Community Concept An assemblage of populations interacting with one another within the same environment Composition is a listing of various species in the community Diversity includes both species richness and species diversity 8 Community Structure Competition When two species compete, the abundance of both species is negatively impacted Predation (or parasitism) Expected to increase the abundance of the predator (or parasite) And reduce the abundance of the prey (or host) 9

4 Habitat and Ecological Niche Habitat The area an organism lives and reproduces in Ecological niche The role a species plays in its community Includes its habitat, and Its interactions with other organisms Fundamental niche - All conditions under which the organism can survive Realized niche - Set of conditions under which it exists in nature 10 Feeding niches for Wading Birds 11 Natural Selection and Adaptation Individuals have heritable variations More individuals produced each generation than environment can support Some individuals have adaptive characteristics Enables increased survival and reproduction Increasing proportion of succeeding generations will have these characteristics Populations become adapted to their local environment through change in individuals 12

5 Artificial Selection of Animals 13 Artificial Selection of Plants 14 Predator-Prey Interactions Predation One living organism, the predator, feeds on another, the prey Predator is usually larger Predator has lower reproductive rate Presence of predators can decrease prey densities, and vice- versa 15

6 Prey Defenses Prey defenses Mechanisms that thwart the possibility of being eaten by a predator Spines Tough Epidermis Poisonous Chemicals Camouflage Bright Coloration Flocking Behavior 16 Mimicry Mimicry One species resembles another species Mimicked species possesses an overt antipredator defense Bt Batesian Mimicry i - Mimic i lacks defense of the organism it resembles Müllerian Mimicry - Mimic shares same protective defense Flower Fly Saw Fly Cucumber Beetle Bald Faced Hornet 17 Bumble Bee Predation, Competition, and Biodiversity Predation by a particular species may reduce competition and increases diversity Such predators are referred to as keystone predators Exotic species May lead to unbridled competition Resultant reduction in biodiversity 18

7 Conservation Biology and Biodiversity Considers all aspects of biodiversity General goal is conserving natural resources for this and future generations Primary goal is the management of biodiversity for sustainable use by humans 19 Conservation Biology and Biodiversity Conservation biology supports certain ethical principles Biodiversity is desirable for the biosphere Extinctions due to human actions are undesirable Ecosystem interactions supporting biodiversity are desirable Biodiversity brought about by evolutionary change has value in and of itself 20 Biodiversity At its simplest level, biodiversity is the variety of species on Earth Estimated that between 5 and 15 million species currently exist Genetic diversity refers to variations among the members of a population Community diversity increases biodiversity Landscape diversity involves a group of interacting ecosystems 21

8 Value of Biodiversity Direct Value Medicinal Value Agricultural Value Crops Biological Pest Controls Pollinators Consumptive Use Value Wood Skins 22 Value of Biodiversity Indirect Value Biogeochemical Cycles Waste Disposal Provision of Fresh Water Prevention of Soil Erosion Regulation of Climate Ecotourism 23 Causes of Extinction 24

9 Causes of Extinction Habitat Loss Occurs in all ecosystems Recent concern focused on tropical rain forests and coral reefs Habitat Fragmentation 25 Alien Species Nonnative species that move, or are moved, into a new ecosystem Often have competitive edge against native species Avenues of Human Introduction Colonization Horticulture and Agriculture Accidental Transport 26 Pollution Any environmental change that adversely affects living things Acid Deposition Eutrophication Ozone Depletion Organic Chemicals Global Warming 27

10 Overexploitation When the harvest is so great that the population becomes severely reduced in numbers The market forces driving the harvest: Exotic Pets Hunting / Poaching Over-Harvesting Fisheries 28 Conservation Techniques Habitat Preservation Keystone Species Metapopulations Small populations isolated because of habitat fragmentation Source Populations Sink Populations Landscape Preservation Landscape protection for one species benefits other wildlife in the same space 29 Conservation Techniques Habitat Restoration - Three Principles Begin as soon as possible before remaining fragments are lost Once natural history is understood, use biological techniques to mimic natural processes Goal is sustainable usage 30

11 Every species ever examined has revealed considerable genetic variation (polymorphism), both within and between populations. p Conservation Genetics Maintenance, Loss, and restoration of biodiversity Prevent genetic erosion To conserve biodiversity, Genetic Diversity Species Diversity Ecosystem Diversity Who needs protection All types of organisms need protection Plant Wild Domestic Animal Wild Domestic Prevent genetic erosion

12 Groups beyond a species Breed/cultivar- a domestic subspecies, based on morphology Variety- a group of individuals that are unique in color Line-a group of related organisms that share a specific trait Landrace-a group of organisms that contain heterozygosity FAO Food and Agriculture Organization of the United Nations Keith Hammond Senior Officer of FAO's Animal Genetic Resources Group The Problem "In the past 100 years we have already lost about 1,000 breeds. Our new findings show that domestic animal breeds continue to be in danger: one third are currently at risk of being extinct," said Keith Hammond, Senior Officer of FAO's Animal Genetic Resources Group.

13 Genetic Erosion FAO has helped collect data from some 170 countries 6,379 breeds of 30 mammalian and bird species 6,379 Bird species in more trouble than mammals Population size data is available for 4,183 breeds 740 breeds extinct 1,335 close to extinction -1,335-2,255 2,049 left 80 country reports show that the number of breeds threatened by extinction is increasing Two breeds lost per week 2,255 more breeds could be lost in next 20 years Importance Domestic animal diversity is unique and cannot be replaced "As much as novel biotechnology may attempt to improve breeds, it is not possible to replace lost diversity. Loss of diversity is forever. Biotechnology will not be able to regenerate diversity if it is lost." Keith Hammond Greatest Threat Export of animals from developed to developing countries, crossbreeding replacement of local breeds These animals are mainly suited to the conditions of the country they come from and they have difficulty coping with the often harsh environment of developing countries.

14 Regions Sub-Saharan Africa total 738 breeds 19% mammals, 34% birds endangered/extinct Asia and the Pacific region 1,251 breeds 14% mammals, 37% birds endangered/extinct Europe 2,576 breeds 49% mammals, 76% birds endangered/extinct America (USA) 259 breeds 35% endangered/extinct Conservation Genetics