Species Diversity Species Diversity Breeding bird species Explanations
Species Diversity
Species Diversity Breeding bird species
Explanations for Global Patterns of Species Richness 1) Morphological diversity, spatial heterogeneity 2) High average rarity - no monocultures – in tropics 3) Climatic constancy of tropics 4) Geological age 5) Special adaptations in extreme (harsh) environments 6) Competitive "balance" 7) Alternating competitive advantages 8) "All niches filled theory" - saturation of community 9) Productivity from A. R. Wallace - 1878
Richness and High Average Rarity Global Plant Richness Local Centers Of Diversity Quality of Data
Richness and High Average Rarity Endemic Plant Species Globally
Richness and High Average Rarity Endemic Plants in Africa
Function of Species in Ecosystems – the airplane analogy
Function of Species in Ecosystems – the airplane analogy – are species the rivets or the passengers?
What happens when we lose too many pieces?
Ecosystem Diversity
What is an Ecosystem? • An ecosystem is a group of interacting organisms (often called the community) in a particular location and the physical environment they inhabit
Walden Pond Shoreline
Pond Ecosystem
Ecotone between pine forest and grassland
Tree Hole Ecosystem
Island Ecosystem
Lake Superior Ecosystem – from space
Lake Superior Ecosystem – at night
Biosphere
Steppe Grasslands North Dakota Masai Mara, Kenya
Ecosystem as Superorganism?
Ecosystem as Collection of Individuals?
Ecosystems of Great Smoky Mountains – from R. H. Whittaker
Ecosystems of Great Smoky Mountains – elevation vs. moisture
Tree species distributions in Great Smoky Mountains
Caption for preceding three figures
Value of Ecosystems Strategic Values
Value of Ecosystems Uniqueness Value
Devil’s Hole – landscape and the hole And the pupfish
Desert Pupfish
Genetic Diversity
Ancestor of the Dog Canis lupus arabs or Canis lupus
Variation in Brassica oleracea
Variation in Brassica oleracea
What is Genetic Diversity? • Genetic diversity is the diversity that occurs in genes of individuals and species • Genetic diversity originates with mutations • It is probably best to think of genetic diversity as occurring at 4 different levels: 1. among species 2. among populations 3. within populations 4. within individuals
Chimpanzee – Pan troglodytes
Among Species Variation - Jiggs and Dorothy Lamour
Among Species Diversity comparison of mitochondrial DNA
Among Populations – Achillea lanulosa
Among Populations – Achillea lanulosa
Within Population - Diversity in shell patterns in a population of Garden Snails - Cepaea
Within Individual Variation Bi-colored eyes in Siberian Huskies
Measuring Genetic Diversity • Among and within populations we often measure genetic diversity by measuring polymorphism - the percentage of genes that are polymorphic (have several alleles) within a population • Polymorphism is sometimes also considered to be a process - the maintenance of genetic diversity within a population • We can also measure genetic diversity by measuring heterozygosity - the percentage of genes at which the average individual is heterozygous
Origin of Genetic Diversity • Genetic diversity originates with mutations • Genetic diversity fuels evolution by allowing organisms to differ from their ancestors and thus be subject to different selection pressures
Selection for white spotting in Dutch Rabbits
Cause of Continuous Variation • The genetic cause for these changes are genes with small phenotypic effect called multiple factors or polygenes – • Polygenes are where several genes interact to produce a quantitative phenotypic effect on a character
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