Topic 4- Natural selection Flashcards
Who worked on theory of evolution?
-Charles Darwin and Alfred Wallace
-Darwin better respected + published book first so wallace forgotten
What is the theory of evolution (natural selection)?
1) Genetic variation arises due to mutations
2) Mutations that are better suited to thier environment live longer and poduce more offspring
3) More offspring wll inherit that mutation
4) This continus over generations cuasing mass changes, as this mutated alleles are more frequent
Difference between Darwin and Wallace ideas?
Darwin= Survival of the fittest (better fitted= more children)
Wallace= speciation (bad mutations = death)
What other works did wallace do?
Warning colouration in animals
What organisms prove evolution and why?
-New emergence of resistant bacteria to antibiotics
-Use of antiobiotics creates a pressured environment as only the few that have resistence survive
-Reproduce at a fast rate, producing large numbers of resistent bacteria
What is the human evidence for evolution?
-Ardi–> 4.4 million
-Lucy —-> 3.9 million
-Homo Habilis—> 2.4 million
-Homo Erectus—-> 1.8 million
-Homo Sapien—-> now
Ardi factfile?
-1.2m tall
-maybe walked uprght
-long toes and arms for climbing
-skull volumee 350^3
ape like + human mix, feet diff to chimpanzees so evolved seperatly
Lucy factfile?
-1.07m tall
-walkled upright
-curved toes for climbing but same bone structure as sapiens
-skull volume 400cm^3
intermediate species chimp mixed with human
Homo habilis factfile?
-short
-long arms
-walked upright
-skull 500-600cm^3
leaky’s found him
Homo erectus factfile?
-1.79m tall
-stongly built
-skull volume 850cm^3
Overall what has changed over time for humans?
-Larger skulls/brains
-Stronger builds
Apart from skeletons, what proves evolution?
-Stone tools
How has the use of stone tools changed?
-Habilis= basic pebble tools made by smashing stones together (used for cutting open nuts)
-Homo sapiens= Pointed arrow heads, spears + hooks (catching fish)
How do we date these tools?
-Radiometric carbon dating: decay of isotope carbon 14 is used to estimate time
-Stratyfying rock layers: layers of sediment (and all things within it) should bee dated to the same time
What limbs prove evolution?
-pentadactyl limbs (5 digits)
-Seen in a number of organsisms indicating a common ancestor
cats, bats, humans, horses
What do we seperate organisms?
4.7
Kingdom
Phylum
Class
Order
Family
Genus
Species
What are the 5 kingdoms?
-Animals
-Plants
-Fungi
-Prokaryotes
-Protists
Phylum subdisivions?
Chordata- backbones
Anthropod- exoskeleton
Annelids- segmented
What are the three domains
Archae—>primative bacteria lives in extreme conditions (hot/cold)
Bacteria—>true bacteria
Eukaryota—> nucleus in a membrane (kingdom protists, animal, plants e.c.t)
Why was the 3 domain system created?
- Species are more distantly related then previously thought
What is selective breeding and how does it work?
-Reproducing parents with the desired characteristic
-Offspring will have those characteristics
-Breed offspring with desired characteristcs
Problems with selective breeding?
-Inbreeding –> significantly reduce genetic variation + reduction of the gene pool (no of diff alleles reduce)
-With the same/ simila genetic make-up a new disease/ environment could kill the entire population
-Small gene pool = greater chance of genetic defects (parents can pass on recessive diseases)
Benefits of selective breading?
-Higher crop yield
-Crops resistent to disease/ animals
-Desired look/taste in animals/food
How does tissue culture work?
1)Choose plant with desired feature
2)Remove fast growing part of plant
3)Using Aseptic technque place on culturing medium with nutrients
4)Once produced shoots and roots can plant
