Natural Selection And Genetic Modification Flashcards
Evolution
A gradual change in the characteristics of a species over time.
(Takes place over millions of years)…
Natural selection
The process allowing species to respond to particular selection pressures.
Stages of natural selection
Variation Overproduction of offspring Selection pressure Survival of the fittest Reproduction Adaptation
Why’s their genetic variation within a species?
Sexual reproduction and new alleles that arise due to mutations.
What’s overproduction of offspring?
Much offspring being produced to create a better chance of passing on genes.
What’s selection pressure?
Competition between individuals due to limited resources of natural factors (eg: light/food).
What’s survival of the fittest?
The organisms with more suitable characteristics having a better chance of survival so that they may reproduce.
What’s adaptation?
Organisms passing on their advantageous allleles, leading to gradual adaptation of a species to their surroundings. These changes only occur from generation to generation.
Industrial melanism
Change from light to dark forms in industrial areas.
Common ancestor
An organism that different species have descended from.
What’s the evidence proving evolution?
Antibiotic resistance
Fossils (hominids)
Development in complexity of stone tools
The pentadactyl limb
Hominids
Human beings and their ancestors.
ARDÍ (4.4 million yrs ago)
LUCY (3.2 million yrs ago)
TURKANA BOY (1.6 million years ago)
How does antibiotic resistance work?
When bacteria develops random mutations that work to a bacterium’s advantage (to resist particular antibiotics) which increases the likelihood of that bacterium’s survival and reproduction.
How do fossils prove evolution?
By arranging the fossils in chronological order, we can see changes over time. (Eg: we share a common ancestor w chimps 6 million years ago)
What species was ARDI? Where was she found and how old is she?
Ardipithecus Ramidus
Ardithipecus ramidus
She was found in Ethiopia, aged 4.4 million years old.
Characteristics of ardi
Apelike big toe for climbing trees Long arms and short legs Chimp size brain Leg structure suggesting she walked upright. Didn’t use hands to walk
What species was lucy? Where was she found? How old is she?
She is of species ASTRALOPITHECUS AFARENSIS and was found in Ethiopia.
She’s 3.2 million years old.
Characteristics of lucy
Arched feet (not climbing)
Longer arms and legs
Larger brain capacity than ardi
Walked more efficiently upright
What species is Turkana boy? Who discovered him and when? How old is he?
He’s of species HOMO ERECTUS. Was found by Richard Leakey in 1984.
He’s 1.6 million years old.
Characteristics of Turkana boy?
Short arms and legs
Similar brain size to that of humans.
Better adapted to walking upright than lucy.
Who came up with the theory of evolution by natural selection?
Charles Darwin
Alfred Russel Wallace
How long did Darwin sail the world and on which ship?
5 years on the HMS beagle.
How have Darwin and Wallace’s theories influenced modern biology?
We now all understand that we all came from a common ancestor.
We can now CLASSIFY organisms based on how closely related they are.
We now understand the risks of ANTIBIOTIC RESISTANCE and how to prevent this.
We now understand the need to CONSERVE as genetic diversity enables adaptations to changing environments.
Order of homo species
Homo habilis
Homo erectus
Homo Neanderthalis
Homo sapien
What type of tools did homo habilis produce?
Pebble tools often from hitting rocks together to produce sharp flakes. They were used for scraping meat off of bones and cracking bones open