Chapter 4 - Evolution Flashcards
What is the definition of Evolution by Natural Selection?
Evolution is a slow continual change of organisms over a very long time through a natural process (without human interference)
What is an alternative theory to Evolution?
Creationism
What do creationists argue? Why can’t we link everything through Evolution?
A designer is responsible for everything and that if Evolution is real then you must be able to link everything.
Not everything dies when/where it can be fossilized.
What is LUCA?
The Last Universal Common Ancestor
Which factors may cause a species to become extinct if they don’t adapt to them?
Increased competition
Changes in the environment
New diseases
New predators
Name Darwin’s key observations
All living things produce more offspring than survive to adulthood
In spite of this, population sizes remain roughly constant
Variation exists among species
Characteristics can be passed from one species to the next
What is the main evidence for Natural Selection?
Fossils
What is Taxonomy? Who invented it?
The study of classification
Carl Linnaeus
What is a genus?
A larger group that all species are placed in. It’s like a surname
What makes each genus different?
All of the species possess similarities which put them in a genus which make them distinct from other genera. The genus is like the surname
A horse and a donkey are in the same genus. They share common characteristics. Are they of the same species? (Clue: think about the potential for breeding)
No. They would mate to produce a mule - a sterile animal
Name the hierarchy of classification
Domain, Kingdom, Phyllum, Class, Order, Family, Genus, Species
D, K, P, C, O, F, G, S
Name the five Kingdoms
Animals, Plants, Bacteria (monera) Fungi, Protists (the bag of leftovers where they don’t fit into any of the others)
Name the three domains for Bacteria. Describe each of them.
Prokaryotes, Eukaryotes and Archea
Prokaryotes - small, no membrane bound organelle, nucleotide/chromosomes, have no histones
Eukaryotes - large, membrane bound organelle, nucleus, have histones
Archea - Small, nucleus(is a prokaryote, have proteins similar to histones
What are the only human ancestors called? What evidence is there to prove they existed?
Hominids
Fossils
What is anthropology?
The study of human behavior
How can we use anthropology to find out about out ancestors?
We use chimps to find out about our ancestors
What is the difference between chimps’ ancestors and ours?
We used stone tools
How can we use archeology to find out about our ancestors?
We study the remains that accompany hominid bones.
By looking at the bones and stone tools (often found with or instead of the bones), this can help us to reconstruct how our ancestors behaved, what they ate and how they might have lived
What is directional selection? (What does it do?)
Altering a species’ phenotype. It’s not evolution, just getting rid of characteristics that don’t work. Acting against one extreme in a range of phenotypes making one become rare and an alternative one become more common
What is stabilising selection? (What does it do?)
It acts against both extremes. The variation of the mode is reduced. It doesn’t lead to evolution. After selection, the mode is in the same position but the range has shortened. E.g. Child birth weight - too big won’t fit through birth canal, too small is underdeveloped. Fewer children are born too big or too small than they were previously as more are a normal weight.
What is disruptive selection? (What does it do?)
Goes/selects against the average. Does lead to evolution. If you keep selecting against the mean, two new species would evolve. E.g. Grey rabbits are the original population, people mate black rabbits together and white rabbits together. As they differ more they recognise each other less and so mate with ones like them more and more before you get a defining split.
What is speciation? What does it rely on?
The formation of a new species from an existing one.
It relies on strategies to reproductively isolate organisms and enough generations to render them unable to produce viable offspring.
What is Allopatric Speciation?
When physical barriers like mountains or islands separate populations and they each adapt to their environments.
What is Sympatric Speciation?
The speciation of organisms within the same habitat. Could be due to organisms going under biological changes, preferring different food species or different mates.
What is Artificial Selection? Does it have another name?
The gradual improvement of animal and plant characteristics over time, for man’s benefit. We try to get eugenics - perfect genes
E.g. dogs were wolves, now cute or cuddly or big or small etc.
Sometimes called Selective Breeding
Give a negative about Artificial Selection
We can lose genes to get monoculture where everything becomes the same. Some genes that are bad right now might be good in the future or vice versa.
Give examples of higher yields as a result of Artificial Selection
Producing more milk (from cows etc.)
Producing more meat (from cows, pigs, sheep etc.)
Producing more fruit (from trees etc.)
What do we use to ‘cut’ DNA?
Restriction Endonucleases - cutting enzymes that attack from within the strand
What are plasmids?
Circles of DNA in bacteria separate from the main chromosome.
cDNA
How do bacteria share plasmids?
They line up next to each other, compare their plasmids and then stick their pilus into the other and grabs it.
Why are plasmids useful to genetic engineering?
We can get bacteria to produce things like insulin and spider silk. It is better for cost and religious reasons and also saves problem with mutations. Muslims and Jews don’t eat pig which is how insulin can also be produced. Bacteria is also simple and easy to GE so it is cheaper.
What is a histone?
A group of basic proteins found in a chromatin
What could a species be described as?
The first name of the organism, the genus is your surname and the species is your first name, identifies who you are in that genus
What is a binomial name?
Universal organisms names which consist of Latin names. The genus comes first and then the species, such as humans are ‘homo sapiens’ where we are the species ‘sapiens’ in the genus ‘homo’. So relatives humans evolved from begin in homo as they had a similar genus/set of phenotypes
