Lecture 1 - introduction of principles of evolution & lecture 2 - classifying life Flashcards
What are the 6 basic concepts of neo-Darwinian evolution?
- reproduction
- excess
- variation
- environmental selection (natural selection)
- divergence
- ancestry
What is the concept of reproduction?
species mate with the same species
What is the concept of excess?
lots of products of reproduction die
What is the concept of variation?
caused by mutation (in non-sexual reproduction)
What is the concept of environmental selection (natural selection)?
e.g. sea/land - some animals are more suited to their environments “survival of the fittest”
What is the concept of divergence?
animals adapt of their environment
What is the concept of ancestry?
we can be related through a series of individuals
What are causes of variation in sexual reproduction?
- independent assortment
- chromosomes
- crossing over - e.g. during meiosis
- mutations
What is biodiversity?
Biodiversity is the variety of life, in all its manifestations. It encompasses all forms, levels & combinations of natural variation.
What is taxonomy?
the science of classification of organisms (hierarchal system)
What is phylogeny?
the study of evolutionary relationships
How did chemists work out how old the world is?
Using isotopes?
What % of time on Earth (Pre-Cambrian Earth) were there only single-celled organisms?
88%
How old is Earth?
4.6 billion years old
What is the order of time periods in descending order?
Quaternary, Neogene, Paleogene, Cretaceous, Jurassic, Permian, Carboniferous, Devonian, Silurian, Ordovician, Cambrian
How can we study biodiversity?
- can study genome of living organisms
- however, only fossils available or extinct organism
- as a result, sequencing of evolution through deep time is aided by a fossil record
Why is the fossil record considered incomplete?
- very few organisms that lived will end up being fossilied
- species of a high taxa may not be preserved - including species that:
- with low preservation potential
- with small population
- that inhabit a small geographical area
- that lived only for only a short period of time
Why is the fossil record biased?
- some environments are more likely to be preserved - e.g. net deposition rather than net erosion.
- fossils of aquatic organisms, or organisms that find their way into aquatic environment are much more likely to be preserved.
- organisms with recalcitrant (resistant) - and therefore more readily preserved - tissues, are more likely to be preserved (e.g. bone, tooth, wood, shell vs sot-bodied organisms)
How has the environment changed through time?
- the environment of plant Earth is spatially variable today
- the environment of plant Earth is temporally variable (diurnal, seasonal)
- but the environment has also changed over longer periods of time (e.g. Milankovitch cycles) or even over vast periods of deep time
can be short, medium or long-term events
What are examples of long-term environmental change through time?
- solar luminosity
- distance between the Earth & its moon (tides) - moon moving away from Earth
- continental drift & plate tectonic events
- changing atmosphere & climate change - live evolved with no oxygen in the atmosphere
- milankovitch cycles
- the evolving biota - the biota available will change based on atmosphere
What the examples of short-medium term & rare events through time?
- large igneous provinces (LIPS)
- shorts-medium term atmospheric/climate change
- super eruptions
- meteorite impacts
- tsunamis
- mass extinctions - 5 times
What is the taxonomy established by Linnaeus?
- Kingdom
- Phylum
- Class
- Order
- Family
- Genus
- Species
Why is it an advantage that evolution works via divergence (splitting system)?
this allows us to place all new species in the hierarchical system
What do we want phylogeny to represent?
taxonomy, as well as speciation events
