Ch 14 Evolution: How change occurs

Question 1

what is evolutionary theory

Answer 1

Change through evolution is a fact, the theory of evolution describe how evolution occurs

• Evolutionary theory is a collection of carefully reasoned and tested hypothesis about how evolutionary changes occur
• It has change a lot over time, existing before and after darwin

Question 2

who was an early scientist to make an evolutionary theory

Answer 2

Jean Baptiste de Lamarck (1744-1829) was one of the first to make a theory

Question 3

what are the parts of lamarcks theory

Answer 3

• A desire to change, organisms are born with an urge to better themselves
• use and disuse, change occurs as organism use their bodies in certain ways. By using a body part it would grow in a helpful way. If not it would shrink
• Passing on acquired traits, trans acquired during a lifetime could be passed onto offspring

Question 4

what happened to lamarcks theory

Answer 4

Lamarcks ideas were consistent for the time, but are now known to be incorrect as changes in genes are passed along, not alteration in body structure achieved during an organisms lifetime

Question 5

how did Charles Lyell influence darwin

Answer 5

Charles Lyell, gave Darwin the geological time needed for evolution to occur. as well as how the environments of modern earth could occur

Question 6

how did artificial selection influence darwin

Answer 6

Artificial selection, demonstrated by farmers who chose what individuals, with the best variations, are allowed to mate. The most desirable traits being selected by humans.

Question 7

how did Thomas Malthus influence darwin

Answer 7

Thomas Malthus, analysed population trends and found that reproduction rates were balanced by many environmental factors. So the environment is the factor controlling animal/species survival/success

Question 8

what are the parts of Darwins theory

Answer 8

• Variation exists in the traits of a population
• The environment puts pressure on the population, ensuring that only some individuals survive and reproduce
• The individuals with certain advantageous variations have an edge over others, and have a higher likely hood of surviving to reproduction
• The variations of the survivors are passed on to their young
• This was coined Survival of the Fittest

Question 9

what left a Hole in Darwins theory

Answer 9

Darwin had no knowledge of Genetics which left a hole in his theory, for he could not explain what mechanism allowed inheritance

Question 10

what roll of gene play in evoltuion

Answer 10

• Carry traits over generations
• the source of random variations, through mutations and the shuffling during meiosis

Question 11

how does evolution act on an organism

Answer 11

• organisms survive not genes, evolution acts on phenotype
• most traits show a large deal of phenotypic variation in a population

Question 12

how does evolution affect populations

Answer 12

• Evolution works on populations
• members of a population share a gene pool
• all possible alleles for a gene occur with different relative frequencies in a gene pool
• Evolution changes the relative frequency of alleles in a gene pool

Question 13

explain genes, fitness, and adaptations

Answer 13

• Genes are passed to the next generation/offspring
• fitness is the characteristic that allows successful reproduction
• adaptations increase the fitness for an individual

Question 14

what is the genetic species definition

Answer 14

• Many species definitions exist today or have existed in the past
• the genetic species definition states that two individuals of the same species can breed and produce fertile young

Question 15

what is a niche

Answer 15

• a niche is the role in an ecosystem and habitat held by a species
• Two different species can’t share the same niche for long
• Competitions occurs within niches but less so between them

Question 16

what is type of isolation is requires for speciation

Answer 16

• the gene pool must first be divided to form reproductive isolation, which ensure adaptations aren’t shared between the two populations
• multiple factors can cause reproductive isolation: physical barriers, behaviour, biochemistry

Question 17

what happens after reproductive isolation

Answer 17

• Once reproductive isolation occurs, the difference between the two population increase
• Once the genes have changed enough that inter breeding can no longer occur, you are left with two different species

Question 18

what is divergent evolution and adaptive radiation

Answer 18

• Divergent Evolution and adaptive radiation splits one species into two or more new species top fill available niches
• causes branches in the evolutionary tree

Question 19

what is convergent evolution

Answer 19

• convergent evolution takes two different groups and makes them similar in some characteristic, generally due to similar environmental pressures
• Analogous structures are similar in form and function but have different origins

Question 20

what is genetic drift

Answer 20

• random changes in a gene pool not driven by natural selection
• common in smaller populations

Question 21

when might a species not change much

Answer 21

when a species is very well adapted to its niche and the niche does not change much, it may not change significantly as it has no need to

Question 22

what is the theory of gradual and rapid evolutionary change

Answer 22

• Gradualism states that evolution occurs steadily at a slow rate
• Equilibrium is the state of little change for a period of time
• when something upsets the equilibrium, rapid change occurs to stabilize a new ecosystem
• things like mass extinctions can upset equilibrium
• punctuated equilibrium is this pattern of change