lecture 3 - origin of species Flashcards
what is life
homeostasis / localised negative entropy
movement, respiration, sensitivity, growth, reproduction, excretion, nutrition
involves the flow of matter, energy and development
what is the DNA paradox?
UV kills DNA but DNA needs light to function
Where and when life arose
earth- 4.5 billion years ago- most accepted theory is the big bang theory- life started 3.5 billion years ago
what is eukaryogenesis
a chance event which caused eukaryotic plants and animals- in this event an archaebacterium engulfed a heterotrophic eubacterium which led to the formation of mitochondria
Ediacaran biota
the segmented organism from 570 MYA- the size of a pinky finger- earliest evidencce of animals- seems like annelid or arthropod
what is the group of animals and fungi called
opisthokonts
dickinsonia
peculiar- 4cm to 1m in length- they were proved as animals because they found cholesterol in the rocks and only animals can produce cholesterol
strange Ediacaran
Rangeomorphs- plant like live under the sea but were animals - fern like
Erniettomorphs - modular or quilted
Cambrian Explosion
reason for animals- 540 MYA
fossils discovered in burgees shale in Canada
all animals evolved in this period and happened over a short period of time
they had soft bodies ( animals like arthropods, worms etc. were seen)
don’t fit into modern taxonomy
Opabinia
Teletubbies like trunk thing- 5 eyes - 7 cm long
causes for Cambrian explosion
physiological change- dissolved oxygen levels allowed active lifestyles
geological change- new shallow seas and niches
geochemical change- new seas means new trace metals - calcium for exoskeleton
biological change- introduction of zooplankton and new predators- increasing selection pressure
how long does it take for an ecosystem to recover from mass extinction
20 million years
