Darwin , Age 22
Darwin notice: many plants – big diversity, therefore some species are really far away from each other
Wind pollination is not effective
Single plants are common in the tropical, fertilize through pollinators, not the wind. Largely evergreen.
Eglossine Bees – Janzen 1971, 23 km per day
Pest pressure hypothesis – survival of seeds is larger when seedlings are more far from the parent.
Reason: pest pressure.
Ant-plant mutualism in Acacia(mutualism): thorns has a hole, where live ants. Ants protects the plant
from herbivores, plant in his turn provides everything for ants living. Feed on proteins and nectar.
Experiment: used the chemical to de ant the trees -> beetles flew on the trees and killed them.
Devil’s garden: no vegetation under the trees Duroia hirsuta. Also found ants, which lived in the trees,
ants produced acid which killed other plants around -> no competition
Giant Amazon Water Lily: difference between wild and botanical garden
2) Epiphytes – the plant that grows on another plant
Common in tropics. Darwin thought they are parasitic. They are not. Epiphytic life form has evolved
independently in many unrelated families = convergent evolution
Bird dispersal, have colorful flowers to attract birds.
2 flowers hypothesis: if pollinated already white, if needs to – blue.
3) found fossils of extinct mammals in Brazil.
Patagonia: abrupt treeline governed by abiotic factors
Familiar and unfamiliar animal groups. Eg. Swans: black & white, bumble bees: too dark(hard conditions
-> to be warm prefer dark fur), Darwin rhea,
4) Galapagos islands: young, volcano islands, long-distance dispersal, a lot of variation among the
species, 5 weeks – foundation of the theory of evolution.
Now – UNESCO worlds heritage site.
How cacti came to the desert: birds pollination
Lecture 15. Genetics 1. Variation
3. Selection – Darwin ne this but not th e others
Genotype – combination of genes
Phenotype – what we observe, natural selection operates on that
Genome – all of the genes in the organism, entire DNA + non-coding regions
Gene: the functional unit of inheritance, DNA sequence composed of codons(3 nucleotides that
makes up the genetic code)
Where does the genetic variation comes from?
Mutation – ultimate source of all genetic variation
Recombination: shuffles up all of the genetic variations that exist
Gene flow: movement of genes from one population to another
Hybridization: mating with another species
Independent assortment & recombination during meiosis generates enormous diversity( > 9 million
possible gamete combinations)
Most genetic variability in a population results from sexual reproduction, but mutation is still an
ultimate source of variability
Mutations in Fruit Fly
Homeotic mutation – leg on a head
McClintock 1983 Nobel Prize for Physiology – Medicine
Jumping genes or mobile geneti