adaption

Question 1

adaption

Answer 1

a change or the process of change by which an organism or species becomes better suited to its environment

Question 2

when does adaption occur

Answer 2

hone an organism displays traits that allow it to live in a particular environment–> all organisms are

Question 3

all organisms are..

Answer 3

adapted to their environment

Question 4

historical views

Answer 4

Lamarck and Erasmus Darwin emphasised the role of inheritance in explaining similarities between organisms. Both argued that modifications were gradual and not random, but arose in response to an organisms environment i.e. they adapted

Question 5

what idea of charles Darwin brought the idea of adaption to the forefront of evolutionary biology

Answer 5

Natural selection

Question 6

Modern synthesis

Answer 6

Neo-Darwinists theory- led by RA fisher, tied the concept of fitness (reproductive success) to those of adaption and natural selection

Question 7

role of natural selection in adaption

Answer 7

if the rate of mutation or drift balances selective pressure then it might appear that the population is not under selection

Question 8

mutations

Answer 8

explores possibilites, NS defines traits that a re adaptive

Question 9

muller ratchet

Answer 9

accumulation of deleterious mutations (which can be removed by sexual reproduction and recombination

Question 10

adaptive/fitness landscape

Answer 10

over time pop. move toward local peaks or optima- the process is dynamic and promoted by mutations and is counteracted by drift and introgression

Question 11

what promotes adaption

Answer 11

• moderate mutation rate
• a small amount of gene flow
• directinal selection
• developmental competence

Question 12

what prevents adaption

Answer 12

• inbreeding
• genetic drift
• large amounts of gene flow
• stabilizing selection

Therefore small populations have less potential for adaption

Question 13

the fundamental niche includes

Answer 13

the total range of environmental conditions that are suitable for existence without the influence of interspecific competition or predation from other species

Question 14

the realised niche

Answer 14

describes the part of the fundamental niche occupied by the species

Question 15

local adaption and NS

Answer 15

any widespread population is likely to experience diff environmental conditions

• as a consequence it will soon consist of a number of sub-population that differs slightly, even considerably
  e. g. rat snake, has geographic ‘race’, that still share a common gene pool

Question 16

example of adaption: moths

Answer 16

Evolution of moths has been studied greatly over the past 200 years. Originally the vast majority had light coloration for camouflage (light colored trees). However due to widespread pollution during the industrial revolution, many of the lichens died out and the trees which peppered moth rested on became blackened by soot, causing most of the light-colored moths to die off. Dark colored moths flourished.
¬ Light colored moths (typica) vs. Dark colored, or melanic moths (carbonaria) flourished.
¬ The first cabronaria moth was recorded by Edleston in Manchester 1848, and over the subsequent years it increased in frequency.

Question 17

any change in the environment is likely to..

Answer 17

lead to local adaption

Question 18

populations consistent of sub-populations because..

Answer 18

any widespread pop. is likely to experience diff environmental conditions in diff parts of its range

Question 19

saltationism

Answer 19

a sudden change from one generation to the next, this is large or very large, in comparison with eh usual variation of an organism.

Darwin sad that the evolutionary process must occur gradually, not in salutation, since saltation are not presently obsessed and extreme deviation from the usual would be more likely to be selected against

Question 20

who disagreed with the theory of saltationism

Answer 20

Darwin, since saltation are not presently observed and extreme deviations from the usual phenotypic variation would be more likely to be selected against

Question 21

cambrian explosion

Answer 21

most major animal group appear for the first time in fossil record some 545million years ago (on the geologic sale this is a relatively short time period)–> a time known as the cambrian explosion

There was once many more body plans
- 545mya a sudden diversity of body plans took place

Question 22

evidence for cambrian explosion

Answer 22

many strange fossils have been found and can be dated to around 545 mya

Question 23

what leads to macro evolution

Answer 23

saltation

Question 24

advocates of salvationism deny the

Answer 24

Darwinian idea of slowly and gradually growing divergence of character as being the only source of the evolutionary process

Question 25

saltation simple

Answer 25

sudden discontinuous ad crucial changes -macro mutations

Question 26

macro evolutions are said to be responsible for the appearance

Answer 26

if new higher taxi including class and order

Question 27

microevolution is thought to be responsible for

Answer 27

the fine adaption below the species level

Question 28

hopeful monster hypothesis

Answer 28

suggests that major evolutionary transformation have occurred in large leaps between species due to macromutation

Question 29

micro/macroevolution is characterised by two extremes

Answer 29

1. gradualism- evolution generally occurs uniformly and by steady and gradual transformations
2. punctuated equilibrium- evolution is marked by isolated episodes of rapid speciation between long period of little or no change

Question 30

gradualism

Answer 30

evolution generally occurs uniformly and by steady and gradual transformations

Question 31

punctuated equilibrium

Answer 31

evolution is marked by isolated episodes of rapid speciation between long periods of little or no change

Question 32

we can look at homologous structures found in the fossils of extinct species and

Answer 32

infer their function by looking at homologues structures in species that do exist eg. claws of dogs and cats have similar functions and structures

Question 33

why must we take great care in establishing function of traits found in extinct species

Answer 33

analogous structures in unrelated species e.g. fns on fish, whales and cuttle fish where there is no common descent

Question 34

homologous structures

Answer 34

similarity by common descent, similar function and form, similar development trajectory

Question 35

analogous structures

Answer 35

diff ancestry, same function, diff developmental trajectory

Question 36

exaptation

Answer 36

adaptation that involves new uses for existing traits

e.g. malleus and incus wer originally part of the lower jaw of reptiles required for chewing

Question 37

co-opted traits are the same as

Answer 37

exaptation

Question 38

linked traits

Answer 38

traits may be selected for because they are linked to something else. e.g. a certain unuseful gene may be linked to a very useful gene

e.g. genetic hitchhiking occurs when an allele changes frequency not because itself is under NS, but because it is near another gene that is undergoing nS

Question 39

Dr Pangloss

Answer 39

believed evolutionary solutions are not optimal

Question 40

example of an imperfect design (Dr Pangloss)

Answer 40

te male urogenital system.
during the evolution of mammals, testes moved from an internal position to a specialised structure outside the body, the scrotum
o Whilst the sperm duct passes ventral to the ureter, the testis migrates dorsal to the ureter during development, requiring a lengthening, not a shortening of the sperm duct

o A more efficient design would be migration of the testis on the same side of the ureters the sperm duct
-progressive adaption

Question 41

once a pathway of progressive adaptations begins

Answer 41

reversals may become competitively disadvantageous or diff to achieve

Question 42

Doll’s law

Answer 42

evolution is not reversible i.e. structures or function discarded during the course of evolution do not reappear in a given line of that organism

Question 43

criticism of the ‘adaptionist adgenda’

Answer 43

adaptationists seek to find adaptive explanation for every characteristic of an organism, however some things ar not ‘for’ the ‘purpose’ etc they seem to be filling.

Somethings that exist are not adaptive- selectively neutral e.g. ear lobe

Question 44

maladaptations

Answer 44

more harmful than helpful, in contrast with an adaptation, which is more helpful than harmful.

Question 45

sickle cell and maladaptations

Answer 45

o	Heterozygosity (HA/HS) or sickle trait leads to some resistance to malaria infection. fitness advantage
o	Homozygosity (HS/HS) however leads to premature death
In one setting the trait is advantageous, in another its deleterious and maladaptive.

Question 46

summary of adaption

Answer 46

occurs when an organism displays traits that allow it to live in a particular environment - all organisms are adapted.

• adaptation is a by-product of NS
• requires a balance between mutation , genetic drift and introgression
• there has previously been much greater diversity
• evolutnitonary solutions ar imperfect, not optimal
• we have to be wary of speculation and just so stories

Question 47

there are many ideas about adaption since

Answer 47

there are many evolutionary biologists

Question 48

evolution of the Eye-Eye

Answer 48

Some scientists think this is how the eye has evolved:
o Simple light sensitive spot on the skin of some ancestral creature gave it some tiny survival advantage, perhaps allowing it to evade a predator. Random changes then created a depression in the light sensitive patch, a deepening pit that made “vision” a little sharper. At the same time, the pits opening gradually narrowed, so light entered through a small aperture, like a pinhole camera.
o Every change gave a survival advantage, no matter how slight. Eventually the light sensitive spot evolved into a retina, the layer of cells and pigment at the back of the human eye. Over time a lens formed at the front of the eye
o In fact, eyes corresponding to every stage in this sequence have been found in existing living species. The existence of this range of less complex light-sensitive structures supports scientist hypotheses about how complex eyes like our could evolve.
o The evolution of the eye is estimated to have taken 364,000 years.

Question 49

darwin theory and the human eye

Answer 49

when evolution skeptics want to attack Darwins theory, they often point to the human eye. How could something so complex, have developed through random mutation and natural selection? Even after millions of years

• If evolution occurs through gradations, how could it have created the separate parts of the eye- lens, retina, pupil- since none of these structures by themselves by would make vision possible? In other words, what good is five percent of an eye?
• Darwin acknowledged from the start that the eye would be a difficult case for his new theory to explain- but not impossible. Through NS diff types of eye have emerged in evolutionary history- and the human eye isn’t even the best one. Because blood vessels run across the surface of the retina instead of beneath it, its easy for the vessels to proliferate or leak and impair vision. So, the evolutional theorist say, the anti-evolution argument that life was created by an ‘intelligent designer; doesn’t hold water if: if God or some other omnipotent force was responsible for the human eye, it was something of a botched design