Unit 1 Notes
1: Diversity
• Biodiversity
o Different life forms in an area
o Usually refers to species
§ About 2 million species named on Earth
• 75% animals
§ May be 6-8 million undiscovered species
o Diversity from central dogma
§ DNA à RNA à proteins
• Animals
o Mostly marine
§ Where animal life evolved
§ Most evolved in Cambrian Period, 500 mya
• Cambrian explosion
• Multicellular life
• Eventual evolution of exoskeleton
§ Major steps in animal evolution
• Sponges: no symmetry, nerves, nor muscles
• Jellies/corals: radial symmetry, nerves, no head
• Bilateria: muscles, directional movement, “wormy” head
o No directional movement in radial symmetry
o Colonization of land
§ Ecdysozoan invertebrates, 450 mya
§ Vertebrates, 375 mya
§ Led to explosion of diversity
• 2 million species
• Half are insects
o Insects
§ Diversity
• Mobility
o Fly to new species and become isolated from original
population
• Toughness
o Exoskeleton protection
• Small size
o Do not require many resources
• Fecundity
o Produce many offspring
• Rigid external genitalia
o Changes in shape create reproductive isolation/speciation
, § 6 orders contain 90% of species
• Orthoptera
o Grasshoppers
• Hemiptera
o True bugs
• Hymenoptera
o Bees, wasps, ants
• Coleoptera
o Beetles
• Lepidoptera
o Butterflies and moths
• Diptera
o Flies
§ Coevolution of Insects and Plants
• Evolution of seed plants in Permian (300-250 mya)
• Seed plants dominated Mesozoic
• Led to radiation of herbivorous groups
o Orthoptera, Hemiptera, Coleoptera
o Vertebrates
§ Includes
• Fish
o < 50% of vertebrates are fish
• Amphibians
• Reptiles
• Mammals
• Birds
§ Feeding Mechanisms
• Herbivores
• Predators
• Detritivores
• Pollinators
• Plants
o 350,000 species
o Major Periods of Evolution
§ Origin of plants
• Charophytes, green algae
• Bryophytes, mosses
§ Early vascular plants
• Seedless vascular plants, ferns
§ First seed plants
• Gymnosperms, conifers
§ Radiation of flowering plants
• Angiosperms
, o Identifying trees
§ Opposite branches
• MAD HORSE
• Maple
• Ash
• Dogwood
• Horse chestnut
§ Alternating branches
• Hickory
§ Oaks
• White oak leaves are rounded
• Red oak leaves are pointed
• Other Ways to Evaluate Biodiversity
o Global Biomass by Taxa
§ Plants have greatest biomass but not greatest number of species
o Genetic Diversity
o Species Diversity
§ a diversity: number of species in habitat
§ b diversity: heterogeneity among communities in a region
• b = 1 means communities are the same
• b = # of habitats means communities are totally different
o Anywhere from 1-# of habitats means somewhat different
!
• First index by Whittaker: 𝛽 = "#
o Number of species in region/average species in habitat
§ g diversity: number of species in a region
o Functional Diversity
§ Tropics have more bird species and more ecological types of birds filling
different niches
o Ecosystem Diversity
§ Variety of ecosystems in a region
• Evaluating Our Biodiversity
o Genetic Diversity
§ 3 species provide 60% of crop plant calories
• Rice, wheat, corn
§ 70% of genetic diversity of crop plants lost in the last 75 years
§ Shift to industrial farming and GM plants
o Species Diversity
§ 2000 Pacific Island bird species extinct from humans
• 15% of global total
§ 20/297 mussel species in NA have gone extinct in the last 100 years
• 60% endangered
§ 40/950 fish species in NA have gone extinct in last 100 years
• 35% threatened or endangered
1: Diversity
• Biodiversity
o Different life forms in an area
o Usually refers to species
§ About 2 million species named on Earth
• 75% animals
§ May be 6-8 million undiscovered species
o Diversity from central dogma
§ DNA à RNA à proteins
• Animals
o Mostly marine
§ Where animal life evolved
§ Most evolved in Cambrian Period, 500 mya
• Cambrian explosion
• Multicellular life
• Eventual evolution of exoskeleton
§ Major steps in animal evolution
• Sponges: no symmetry, nerves, nor muscles
• Jellies/corals: radial symmetry, nerves, no head
• Bilateria: muscles, directional movement, “wormy” head
o No directional movement in radial symmetry
o Colonization of land
§ Ecdysozoan invertebrates, 450 mya
§ Vertebrates, 375 mya
§ Led to explosion of diversity
• 2 million species
• Half are insects
o Insects
§ Diversity
• Mobility
o Fly to new species and become isolated from original
population
• Toughness
o Exoskeleton protection
• Small size
o Do not require many resources
• Fecundity
o Produce many offspring
• Rigid external genitalia
o Changes in shape create reproductive isolation/speciation
, § 6 orders contain 90% of species
• Orthoptera
o Grasshoppers
• Hemiptera
o True bugs
• Hymenoptera
o Bees, wasps, ants
• Coleoptera
o Beetles
• Lepidoptera
o Butterflies and moths
• Diptera
o Flies
§ Coevolution of Insects and Plants
• Evolution of seed plants in Permian (300-250 mya)
• Seed plants dominated Mesozoic
• Led to radiation of herbivorous groups
o Orthoptera, Hemiptera, Coleoptera
o Vertebrates
§ Includes
• Fish
o < 50% of vertebrates are fish
• Amphibians
• Reptiles
• Mammals
• Birds
§ Feeding Mechanisms
• Herbivores
• Predators
• Detritivores
• Pollinators
• Plants
o 350,000 species
o Major Periods of Evolution
§ Origin of plants
• Charophytes, green algae
• Bryophytes, mosses
§ Early vascular plants
• Seedless vascular plants, ferns
§ First seed plants
• Gymnosperms, conifers
§ Radiation of flowering plants
• Angiosperms
, o Identifying trees
§ Opposite branches
• MAD HORSE
• Maple
• Ash
• Dogwood
• Horse chestnut
§ Alternating branches
• Hickory
§ Oaks
• White oak leaves are rounded
• Red oak leaves are pointed
• Other Ways to Evaluate Biodiversity
o Global Biomass by Taxa
§ Plants have greatest biomass but not greatest number of species
o Genetic Diversity
o Species Diversity
§ a diversity: number of species in habitat
§ b diversity: heterogeneity among communities in a region
• b = 1 means communities are the same
• b = # of habitats means communities are totally different
o Anywhere from 1-# of habitats means somewhat different
!
• First index by Whittaker: 𝛽 = "#
o Number of species in region/average species in habitat
§ g diversity: number of species in a region
o Functional Diversity
§ Tropics have more bird species and more ecological types of birds filling
different niches
o Ecosystem Diversity
§ Variety of ecosystems in a region
• Evaluating Our Biodiversity
o Genetic Diversity
§ 3 species provide 60% of crop plant calories
• Rice, wheat, corn
§ 70% of genetic diversity of crop plants lost in the last 75 years
§ Shift to industrial farming and GM plants
o Species Diversity
§ 2000 Pacific Island bird species extinct from humans
• 15% of global total
§ 20/297 mussel species in NA have gone extinct in the last 100 years
• 60% endangered
§ 40/950 fish species in NA have gone extinct in last 100 years
• 35% threatened or endangered
