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
24
Q
How are cladograms formed?
A
- through molecular similarity (genetic code is universal)
- DNA base sequences
- more specific (to distinguish from the same family)
- protein sequences
- changes in DNA sequence will be observed faster
- DNA base sequences
- sequence of divergence in clades (principle of parsimony)
25
Q
What is the hierarchy of taxa?
A
- species → genus (genera) → family → order → class → phylum → kingdom → domain
26
Q
What are the 3 domains of organisms and their features?
A
- bacteria
- no histones (and chromosomes)
- no introns (rare)
- cell walls: peptidoglycan -
- cell membrane: glycerol-ester lipids, unbranched side chains, d-form of glycerol
- archaea
- protein with DNA (similar to histones)
- some introns
- cell wall: no peptidoglycan
- cell membrane: glycerol-ester lipids, unbranched side chains, d-form of glycerol
- eukaryota
- histones + DNA
- introns
- cell wall: no peptidoglycan
- cell membrane: glycerol-ester lipids, unbranched side chains, d-form of glycerol
27
Q
Where are archaeans found?
A
- ocean surface
- deep ocean sediments
- oil deposits (below Earth surface)
- water with high salt concentrations
- boiling temp.
- methanogens (obligate anaerobes)
- methane as waste
- intestines of cattle + guts of termites
- marsh gas production
28
Q
How are eukaryotes classified?
A
- plants
- animals
- fungi
- protoctista
29
Q
What is an example of classification?
A
Human
- kingdom: animalia
- phylum: chordata
- class: mammalia
- order: primates
- family: hominidae
- genus: homo
- species: sapiens
Date palm
- k: plantae
- p: angiospermophyta
- c: monocotyledoneae
- o: palmales
- f: arecaceae
- g: phoenix
- s: dactylifera
30
Q
What is an example of reclassification of a species?
A
- reclassification → a new taxa could be formed or species from a taxa can be moved
- which apes belong to Hominidae family?
- originally apes in Pongidae
- chimpanzees and gorillas closer to human → moved to the same fam
- chimpanzees same genus
- Pongidae: orang-utans
31
Q
What are the advantages of natural classification?
A
- easy identification of species
- unknown organism → kingdom, phylum, class, etc. assigned
- species name created
- unknown organism → kingdom, phylum, class, etc. assigned
- common ancestral species in groups → similar characteristics
- prediction of characteristics in a group
32
Q
What is a dichotomous key?
A
- tool helping in identification of species
- numbered series of pairs of descriptions
- one has to clearly match species
- lead to another pair or identification
33
Q
What are the features of bryophyta?
A
- plant phylum (mosses, liverworts, hornworts)
- rhizoids — no true roots
- simple stems and leaves / thallus
- no xylem or phloem
- no cambium, no true trees and shrubs
- no pollen produced
- no ovaries / ovules
- no seeds
- no fruits
34
Q
What are features of filicinophyta?
A
- plant phylum (ferns)
- roots, stems and leaves present
- xylem + phloem
- no cambium, true trees or shrubs
- no pollen, ovaries (ovules), seeds or fruits
35
Q
What are features of coniferophyta?
A
- plant phylum (conifers)
- roots, stems, leaves
- xylem + phloem
- cambium
- secondary thickening of stems and roots
- plants into trees and shrubs
- pollen produced in male
- ovules in female
- seeds spread
- no fruits
36
Q
What are features of angiospermophyta?
A
- plant phylum (flowering plants)
- roots, stems, leaves
- xylem + phloem
- cambium
- thickening of stems and roots
- plants → trees and shrubs
- pollen produced by anthers
- ovules in ovaries
- seeds and fruits
37
Q
What are features of porifera?
A
- animal phylum (sponges)
- no mouth / anus
- no symmetry
- internal spicules (skeletal needles)
- pores on surface → water filtered, feeding
38
Q
What are the features of cnidaria?
A
- animal phylum (hydras, jellyfish, corals, sea anemones)
- mouth only
- radial symmetry (circle)
- soft but hard corals secrete CaCO3
- tentacles around mouth (rings)
39
Q
What are the features of platyhelminthes?
A
- animal phylum (flatworms, flukes, tapeworms)
- mouth only
- bilateral symmetry (two ends, up and down distinguished)
- no skeleton
- flat bodies (ribbon)
- no blood or gas exchange
40
Q
What are the features of mollusca?
A
- animal phylum (bivalves, gastropods, snails, quid, octopus,)
- mouth and anus
- bilateral symmetry
- shells made of CaCO3
- fold in body wall = mantle
- secretes shell
- rasping radula for feeding
41
Q
What are the features of annelida?
A
- animal phylum (marine, bristleworms, leeches)
- mouth and anus
- bilateral symmetry
- internal cavity with fluid (pressure)
- ring-shaped segments + visible blood vessels
42
Q
What are the features of arthropoda?
A
- animal phylum (insects, arachnids, myriapods, crustaceans)
- mouth and anus
- bilateral symmetry
- external skeleton (plates of chitin)
- segmented bodies
- legs with joints
43
Q
What are the features of bony ray-finned fish?
A
- scales = bony plates
- gills covered by an operculum
- one gill split
- no limbs
- fins supported by rays
- eggs and sperm fertilised externally
- in water
- swim bladder with gas for buoyancy
- no constant temp
44
Q
What are the features of amphibians?
A
- skin permeable to water and ashes
- simple lungs with small lungs + moist skin
- gas exchange
- tetrapods with pentadactyl limbs
- four legs (adults)
- external fertilisation
- larval stage in water, adult on land
- eggs coated in projective jelly
- no constant temp
45
Q
What are the features of reptiles?
A
- impermeable skin
- scales of keratin
- lungs with folding → increase in surface area
- tetrapods with pentadactyl limbs
- four legs (mostly)
- internal fertilisation
- soft-shelled egg
- teeth (one type, no living parts)
- no constant temp
46
Q
What are the features of birds?
A
- feathers (keratin)
- lungs with para-bronchial tubes
- ventilated using air sacs
- tetrapods with pentadactyl limbs
- two legs and two wings
- internal fertilisation
- hard-shelled eggs
- beak (no teeth)
- constant temp
47
Q
What are the features of mammals?
A
- skin → follicles with hair (keratin)
- lungs with alveoli, ventilation → ribs and diaphragm
- tetrapods with pentadactyl limbs
- four legs (two legs + two arms / wings)
- internal fertilisation
- birth to young + feeding (mammary glands)
- teeth different types (living core)
- constant body temp
48
Q
What is a molecular clock?
A
- differences in DNA → mutation
- constant rate (used as molecular clock)
- number of differences → how long ago groups split from common ancestor
49
Q
What are analogous structures?
A
- convergent evolution
- similarities in structure and function
- evolved independently
50
Q
What is the result of cladistics?
A
- reclassification
- traditional classification (morphology) ≠ evolutionary origins of groups
- merging, dividing, transferring
- new classification is closer → higher predictive value
- unnoticed similarities and differences
51
Q
What is an example of cladistics used to reclassify a group?
A
- figwort family (angiosperms)
- Scrophulariaceae used to be 8th largest
- 16 genera (similar morphology) → 275 genera
- cladograms of figwort family
- 3 chloroplast genes compared
- figwort not a true family
- 5 clades incorrect
- result
- 2 small fam merged with figwort
- 50 genera moved
- 12 genera of parasitic plants moved
- 2 new fams (13 genera and 2 genera)
52
Q
What is a gene pool?
A
- consists of all genes and their different alleles, present in interbreeding population
- genetic equilibrium = all members have equal chance of contributing to gene pool
53
Q
What are patterns of natural selection?
A
- stabilising — removing extreme varieties
- average birth weights»_space; low or high weight (humans)
- medium sized clutch (number of eggs)
- disruptive — removing intermediate varieties, favouring extremes
- asymmetric lower part of red crossbills → extraction of seeds from conifer cones
- specific part needed for the task, straight bill wouldn’t make it
- directional — one extreme of a range of variation is better adapted
54
Q
What are different categories of reproductive isolation?
A
- speciation = formation of new species → splitting into existing population
- barriers isolate gene pool
- speciation occurs
- geographic (allopatric) isolation
- fish in different lakes
- fluctuation of water levels
- rainy season → recombination (new species formed)
- fish in different lakes
- same geographic area = sympatric speciation
- behavioural – related individuals differ in behaviour → attract members of own population
- temporal – prevents species from interbreeding due to differences in the timing of mating or fertility, such as having different mating seasons
55
Q
What is gradualism?
A
- species slowly change through a series of intermediate forms
- beak length, cranial capacity
- absence of intermediate forms in fossils (explained as imperfections)
56
Q
What is punctuated equilibrium?
A
- long period of stability punctuated by periods of rapid evolution
- lack of intermediate species in fossils → no long sequence of them
- geographic isolation + new niches → rapid speciation
- common in prokaryotes and insects
57
Q
What happens during speciation due to polyploidy?
A
- polyploid organism — more than 2 sets of homologous chromosomes
- chromosomes from same ancestral species
- multiplication for meiosis → meiosis doesn’t occur
- haploid gamete fused with diploid (reproductively isolated)
- polyploid plant can self-pollinate → sympatric speciation
- commonly in plants
58
Q
What is an example of speciation by polyploidy?
A
- Allium genus (onion, leek, garlic, chive)
- polyploidy common → reproductively isolated but similar populations
- asexual reproduction (polyploidy advantage)
- Allium angulosum & oleraceum
- one has 16, the other 32
