XII Chap 7 Evolution Flashcards
How old are each of these?
- Universe
- Earth
- Life on Earth
- First cellular life on Earth
Universe - 20 billion years
Earth - 4.5 billion years
Life on Earth - 4 billion years
First cellular life on Earth - 2000 million (2 billion) years
What is the big bang theory?
universe expanded, temperature came down;
H and He formed and condensed under gravitation to form galaxies;
in the milky way, earth formed - no atmosphere present, only water vapour, methan, CO2 and NH3 (ammonia) released from molten mass;
H & O separate from water vapour, H escapes and O2 combines with ammonia and methane to form water, CO2 and more;
ozone forms;
water vapour condenses to rain and then to oceans
What were the theories (other than big bang) about the origin of life?
- Panspermia - spores (units of life) transferred to different planets
- Spontaneous generation - from decaying/rotting matter - Louis Pasteur disproved, life can only come from pre-existing life
- Chemical evolution - formation of diverse organic molecules from inorganic matter, preceded biological evolution
What does “biogenesis” mean?
Start of life on earth (4 billion years ago)
How did Miller’s experiment recreate pre-life conditions on earth?
Closed flask; CH4, H3, NH3, water vapour at 800° C
The present day theory of evolution emerged in _______
19th century
What was the name of Charles Darwin’s ship?
HMS Beagle
Who is the person who also supported Darwin in his theory and made similar journeys, observations and collected artefacts?o
Alfred Wallace
What are evidences for evolution?
Fossils
Sediments
What is the embryonical support for evolution? Is it still upheld?
Ernst Heckel => embryos have gill slits
Disproved by Karl Ersnt von Baer => we don’t have organs of any other species
What is divergent evolution?
Same structures develop in different directions because of different needs;
points to common ancestry
The similar structures shared by creatures in divergent evolution are ____________
homologous
What is an example of divergent evolution in mammals?
Humans, cheetah, whales and bats - similar bone patterns in forelimbs: humerus, radius, ulna, carpals, metacarpals, phalanges
The vertebrae hearts and brains are examples of this kind of evolution.
Homologous and divergent
Thorn and tendrils of Bougainvillea and Cucurbita are an example of this type of evolution.
Homologous and divergent
The wings of butterfly and birds are example of this type of evolution
Convergent and analogous
The eye of octopus and mammals are example of this type of evolution
Convergent and analogous
The flippers of dolphins and penguins are example of this type of evolution
Convergent and analogous
Sweet potato and potato are example of this type of evolution
Convergent and analogous
Sweet potato is a _____ modification and potato is a _____ modification
root; stem
What is convergent evolution?
different structures (analogous) but they serve the same function due to similar habitat
Similarities in proteins and genes in organisms points to ________
common ancestry
No variant is completely wiped out in course of evolution. T or F?
True
When organisms evolve due to building resistance against drugs like antibiotics, it’s called evolution by _________
anthropogenic action
What are Darwin’s Finches?
Small, black birds;
Galapagos Islands;
originally seed-eating;
some evolved to insectivorous and vegetarian
What is adaptive radiation
Evolution of different species in a geographical areas starting from 1 point and radiating to other habitats
Darwin’s finches and Australian marsupials are examples of adaptive radiation. T or F?
True
Australian Marsupial and placental mammals show ________ type of evolution
convergent
When there’s more than one adaptive radiation in an isolated geographical area with different habitats, one can call this _______ type of evolution
convergent evolution
The rate of appearance of new forms are unrelated to the lifecyles / life spans of species. T or F?
False, they are directly related; longer the life span, longer the time to see variation
Adaptive ability is the same as “fitness”. T or F?
False;
adaptive ability is inherited / genetic, fitness is the end RESULT of ability to adapt
Lamarck a French naturalist suggest which theory that is now no longer upheld?
Evolution happens because of the use / disuse of organs
Evolution is a process in the story of ________
Evolution is an end-result in the story of ________
world;
life on earth (natural selection is the process, evolution is the result of that process)
Darwin was possibly influenced by ________’s work on populations
Thomas Malthus
In theory, populations can grow exponentially if everyone reproduces maximally;
______________ limits population size in reality
Competition for resources
What was the novelty in Darwin’s theory - given there were already theories that had similar positions?
Heritable variations lead survivors to reproduce and leave more progeny
What were the differences in the work of Darwin and deVries?
Darwin - evolution is due to minor heritable variations; gradual, directed
deVries - evolution is due to large differences arising suddenly; random and directionless
deVries believed mutations cause speciation and hence called it _______
saltation - single step large mutation
What is the Hardy-Weinberg principle
Allele frequency in a population is stable and constant from generation to generation; all of the frequencies add up to 1
What is genetic equilibrium?
Hardy-Weinberg principle
How does one calculate the frequency of allele AA?
If frequency of A is p, frequency of AA is p^2
How does one calculate the frequency of allele Aa?
Freq of A is p, Freq of a is q
=> 2pq
The HW principle can be illustrated through the expansion of which binomial?
(p+q)^2 = 1
When frequency measured differs from expected value indicates a _________
evolutionary change (due to change of frequency of alleles in population)
What are the factors that affect the HW equilibrium?
- Gene migration/flow
- Genetic drift
- Mutation
- Genetic recombination
- Natural selection
Differentiate genetic migration and flow
Migration - section of population migrates to new place
Flow - multiple migrations continuously
What is genetic drift?
Migration by chance
What is the founder effect?
So much change in allele frequency that the new population is different species altogother
The new population are called the founders in a founder effect. T or F?
False, original population are called the founders
National selection can lead to 3 types of changes:
Stabilization - more individuals acquire the mean character value
Directional change - more individuals acquire a value other than the mean character
Disruption - more individuals acquire peripheral character values at both ends of the distribution
What happened at these different points in the history of evolution? 2000 million years ago - 500 mya 350 mya 320 mya 250 mya 65 mya 15 mya
2000 million years ago - first cellular life
500 mya - invertebrates
350 mya - jawless fish / fish with strong stout/fins could move on land and water (evolved into amphibians => reptiles => dinosaurs OR back to water)
320 mya - sea weed / plants
250 mya - reptiles moving back to water
65 mya - dinosaurs extinct
15 mya - primates - Dyopithecus and Ramapithecus
What happened at these different points in the history of evolution? 3-4 mya 1.5 mya 100,000-40,000 ya 75-10,000 ya 18,000 ya 10,000 ya
3-4 mya - man-like primates, Australopithecines, Homo habilis 1.5 mya - Homo erectus 100,000-40,000 ya - Neanderthal 75-10,000 ya - Modern Homo sapien 18,000 ya - pre-historic cave art 10,000 ya - agriculture
Dinosaurs were essentially “land reptiles”. T or F?
True
The T-Rex was _____ feet tall
20
Alongside dinosaurs, smaller reptiles still existed. T or F?
True
The first mammals were ________
shrews, vivaparous and highly intelligent in avoiding danger
When reptiles declined mammals took over. T or F?
True
Mammals exist only on land, not in water. T or F?
False
water-only mammals: whales, dolphins, seals, sea cows
Dryopithecus was ____-like and Ramapithecus was ____-like but both walked like chimps/gorillas
ape;
man
Characteristics of Australopithecines?
Eastern Africa,
<4 ft.
walked upright,
hunted with stone weapons, but mostly ate fruit
__________ was the first human-like being
Homo habilis
Size of the brains of homo habilis, Neanderthal and homoerectus
Homo habilis = 650-800cc
Homo erectus = 900cc
Neanderthal = 1400 cc
Characteristics of Homo habilis?
First human-like being,
650-800cc,
no meat
Characteristics of Homo erectus
900cc,
probably ate meat
Characteristics of neanderthals
east and central Asia,
1400cc,
protected body with hides;
buried their dead
Origin of life can only be understood with origin of universe/earth. T or F?
True
First cellular life preceded chemical evolution. T or F?
False
Variations in populations lead to variable _______
fitness
Habitat fragmentation and genetic drift lead to _________
new species / evolution
Homology (common origin) is accounted for by the idea of _____________
Branching descent (species having variations that link them to a common ancestor)
What are the evidences of evolution?
- Study of comparative anatomy
- Fossils
- Comparative biochemistry
The most fascinating aspects of the evolution of humans involve evolution of _____ and ___________
brain and language
