Topic 2 - Life, Diversity; Introduction to Natural Selection Flashcards
Biological diversity
the difference between living things
The variety within and among living species
Things that are alive can
Reproduce
Grow
Have functional activity: movement, response to stimuli, metabolism, catabolism, excretion
Adaptation: can change over (evolutionary) time in response to the environment
The simplest division
Alive and not alive
Examples of things alive and not alive
rock
prion
coral
virus
rock - no
prion - composed of a protein that can fold in multiple ways. One way of folding is transmissible to other proteins. Causes mad cow disease.
a coral is alive. does all 4
A prion does none. It is not alive.
A virus can adapt but cannot do the other 3. It is not considered alive.
What are the broadest taxonomic categories
Domains and Kingdoms
Each kingdom groups together
all forms of life having certain fundamental characteristics
A species is
a group of individuals that regularly breed together
How were organisms grouped until about 50 years ago?
Based on observations of behaviour, shape, size etc
Plants = organisms that don’t move and appeared to make their own food
Animals: organisms that could move about and relied on other organisms for food
in 1969
Scientist introduced a system of 5 kingdoms, categorized according to cell type and method of obtaining energy
Modern taxonomy
Has 3 domains and 6 kingdoms based on molecular characteristics
Eukarya vs Prokarya
Eukarya = single or multicelllular and have membrane bound organelles
Prokarya = single celled and dont have membrane bound organelles
3 domains
What are prokarya
(1) Eukarya
(2) Bacteria
(3) Archaea
Prokarya - Bacteria and Archea (archea are prokaryotes that are not bacteria)
6 kingdoms
Animals
Plants
Fungi
Protista
ALL EUKARYOTES
Bacteria
Archaea
PROKARYOTES
Bacteria & Archaea
Single celled, free living or colonial
Cells are small, do not have membrane bound organelles (nucleus, mitochondria or chloroplasts)
Numerous - more bacteria in one mouth than all humans that ever existed
Eukarya - protists
Mostly single celled
Diversity of lifestyles
Plant-like, fungi-like and animal-like types
Eukarya - plants
Multicellular
Make their own food
Largely stationary
Eukarya - fungi
Multicellular
Rely on other organisms for food- tendrils into substrate
Reproduce by spores
Eukarya - Animals
Multicellular
Rely on other organisms for food
Mobile for at least part of the life cycle
How are organisms classified?
Start with broad categories with a few fundemental charecteristics
As you mive through the classification, create more specific subcategories
A species is a group that regularly breeds together
The tree of life
Based on evolutionary relationships
All life stems from divergence of a single ancestor
Early divergence resulted in major groupings (eg domains) which correspond to divergences which happened very early in lifes history
Minor groupings correspond to more recent divergence
The origin of divergence
was due to mutations in DNA and RNA
The nucleus first hypothesis of Eukaryote differntiation
The Endosymbiotic Theory. The first eukaryote may have originated from an ancestral prokaryote that had undergone membrane proliferation, compartmentalization of cellular function (into a nucleus, lysosomes, and an endoplasmic reticulum), and the establishment of endosymbiotic relationships with an aerobic prokaryote, and, in some cases, a photosynthetic prokaryote, to form
mitochondria and chloroplasts, respectively.
A prokaryote engulfs a nucleus, then a mitochondria or plants
History of Charles Darwin
Born in 1809
Went to med school in Edinburgh and was bored. Was trained in taxidermy by John Edmundstone, a freed slave
After graduation became a collector on the HMS beagle where his voyage was paid for by rich people for the samples he brought back
In the Galapagos islands off Ecuador, he observed many animals including Darwin’s finches
Why were there different kinds of finch on different islands that were similar to, but different from the others and those on the mainland?
History of Alfred Russel Wallace
Born in 1823
Always wanted to understand the distribution of species even before she was a collector
Went to the Amazon because his exposure to animals from there in museums had indicated there was a big variety of animals
Was a bad choice- lots of species but not many of each (low abundance). Also hard to collect and dangerous. His bro died of yellow fever there.
Boat nearly sank near Barbados but did not.
Luckily the amazon river is huge and not all species can cross it. Noticed the birds were the same on both sides of the river as they can fly but the monkeys were not.
Decided that natural barriers can separate species and therefore Islands are a good place to study this.
Went to Malaysia
Published a paper on the physical distribution of species
Corresponded with Darwin
Wanted him to read a manuscript on the origin of species abd pass it on to Charles Lyelle of the Linnean society
The publication story
We don’t know what happened next.
What happend between Lyelle receiving this and Darwin submitting his own is unclear
Whether Wallace nudged him to finish it faster or gave him additional info he needed we do not know
Both were presented at the same time
Darwin had books worth of thoughts so had clearly been thinking about it
The theory did not make a big splash, took time but became a phenomenon
