Evolution Flashcards
1
Q
What is evolution?
A
- change in frequency of alleles within a gene pool from one generation to the next
- cumulative change in the heritable characteristics of a population
- individuals do not evolve (populations do)
- evolution ≠ improvement
2
Q
What is variation?
A
- individuals of the same species are different
- offspring’s to parents
- otherwise no evolution
- prerequisite of evolution
- mutations
- meiosis
- crossing over
- random assortment
- sexual reproduction
3
Q
Why are offsprings overproduced?
A
- prerequisite for evolution
- more offspring’s than can be supported
- rate of this process depends on reproductive strategy
- passing on characteristics to offsprings
4
Q
What is an adaptation?
A
- a characteristic helping to deal with some particular environmental factors and problems
- result of evolution
- trait = structure and function are intertwined
5
Q
What is fitness?
A
- sum of all adaptations defining how good is the creature in surviving and reproducing
- differs between individuals in a population
6
Q
What is survival success?
A
- how good a species is at surviving
- different fitness —> more or less likely to survive
- reproductive success — how many offsprings an individual has
7
Q
What is the danger of too many mutations?
A
- the amount of offsprings wouldn’t matter if there would be many mutations
- rare
- what influences evolution is also preservation of traits and genes
8
Q
What is the process of evolution?
A
- beneficial adaptations —> bigger reproductive success
- more likely to survive (so can reproduce)
- more individuals with this adaptation are born
- frequency increases
- population changes —> evolution
9
Q
What is the difference between natural and artificial selection?
A
- natural selection —> environmental pressures
- artificial selection —> a person selects a species with a desired outcome
10
Q
How is natural selection observed through finches on Daphne Major?
A
- adaptive radiation — one species adapted to different environments on Galápagos Islands
- during drought finches beaks became larger (to get seeds from hard cacti)
- during rain beaks became smaller
11
Q
How is natural selection observed among bacteria?
A
- some bacteria are resistant to antibiotics
- at some concentration, the rest dies, resistant bacteria stay
- multiplication
- entire population is resistant
- at some concentration, the rest dies, resistant bacteria stay
12
Q
How are peppered moths example of evolution?
A
- direct observation
- peppered small moths
- at day: resting on tree trunks
- light coloured (with black spots)
- invisible on trees covered with lichens
- melanic form of moths
- dark coloured
- visible on trees
- industrial revolution —> air pollution (lichens disappear)
- dark form more adapted —> dominance
13
Q
How are fossils evidence for evolution?
A
- parts of organic dead matter become saturated in minerals —> rocks
- hard parts: bones, shells, scales
- soft parts decay
- evidence
- comparison of anatomy
- sequences
- different striata (layers) —> organisms from different ages
- the more organic matter, the newer it is
- intermediate specimens
14
Q
How is a horse proof for evolution?
A
- fossils
- horses ancestors had 3-4 toes
- nowadays horses have 1 toe
15
Q
What is an example of selective breeding?
A
- selection can cause evolution
- teosinte —> modern corn
16
Q
What are homologous structures?
A
- evolved from the same structure
- different purposes
- remains of old template can be found (from the same ancestor)
- example: pentadactyl limb (5 fingers)
- different types of locomotion —> different shapes
- example: pentadactyl limb (5 fingers)
17
Q
What is adaptive radiation?
A
- source of homologous structures
- population settles in new habitat
- selective pressures increase
- splitting into specialised subpopulations —> separate species
- example: cichlid (family of fish) came from one population
- African lakes
18
Q
What is speciation?
A
- selective pressure acts for long time
- differences accumulate
- population splits
- subpopulations become different species
- determined by molecular evidence (DNA)
19
Q
What is classification?
A
- systematic arrangement in groups or categories according to established criteria
- taxonomy — orderly classification of organisms according to their presumed natural relationships
20
Q
What is natural taxa?
A
- trying to classify species with other species that are the most similar to them
- all members of genus (and higher taxons)
- common ancestor
- example of artificial classification: birds, bats, insects together
- ability to fly
- no common ancestor
- convergent evolution → organisms superficially similar
- adaptive radiation → similar organisms look different
- molecular determination
21
Q
What is binomial nomenclature?
A
- Carolus Linnaeus
- universal nomenclature (science is international)
- Genus [generic name] species [specific name]
- Homo sapiens
- Felis domesticus
22
Q
What is a clade?
A
- a clade is a group of organisms that have evolved from a common ancestor
- share a common characteristic (different than other species)
- not all members of a clade exist today (dinosaurs)
23
Q
What are branching points on cladograms?
A
- nodes
- specification event
- common ancestor splits into more species
