A4.1-evolution and speciation

Question 1

current definition of evolution

Answer 1

the process of cumulative change in the heritable characteristics of a population

Question 2

things to remember regarding evolution

Answer 2

-not linear
-gradual, continuous, subtle process
-POPULATIONS EVOLVE, not individuals
-no direction

Question 3

Lamarckism

Answer 3

theory stated; organisms acquired characteristics through their lifetime if needed and then pass them onto their offspring

-theory was disproven

Question 4

why lamarckism is wrong

Answer 4

-it is rather a slow process
-acquired characteristics of an organism in its lifetime does not affect genetic material

Question 5

micro and marco evolution

Answer 5

micro= small allele changes in small amount of time

macro=large changes in a group over long period of time

Question 6

point of evidence for evolution

Answer 6

-RNA/DNA amino acid sequences
-selective breeding
-homology and analogy
-fossil record
-direct observation

Question 7

RNA/DNA/ amino acid sequence for evidence of evolution

Answer 7

-you can compare nucleic acids and protein data from many organisms to examine evolutionary relationships.
-soft wear can compare differences and similarities of codes, to see how closely related
-all organisms have a single shared genetic code that translates the sequence of nucleotides in a gene into corresponding amino acid chain

Question 8

pseudogenes

Answer 8

homologous genes that have lost their function

Question 9

selective breeding as evidence for evolution

Answer 9

breeding domestic animals is good to study changes in heritable characteristic
=breeding members of species with desired traits

-shows that species can change over time due to human intervention and mimics natural selection, where organisms with advantageous traits are more likely to survive.

Question 10

homologous and analogous structures as evidence for evolution

Answer 10

homologous= same structure, different function, different evolution from similar origin, e.g; pentadactyle limb
is DIVERGENT EVOLUTION= when new species develop traits that differentiate them from their ancestor

analogous= different structure, same function, different evolutionary origins, e.g;wings
is CONVERGENT EVOLUTION= unrelated species develop similar traits when living in similar environments

Question 11

Vestigial Structures

Answer 11

structures found in an organism that is no longer in use but may have been useful at some point in the organism’s life.

Question 12

Similarities in Early Development as evidence for evolution

Answer 12

Scientists look at embryos of different organisms and find that many embryos resemble one another.

Question 13

fossils as evidence for evolution

Answer 13

Layer of rock indicates age of fossil (lower in rock layers = older fossils)

Question 14

what is speciation

Answer 14

process in which one species splits into two or more species

-increases total number of species on earth

-occurs when gene flow is interrupted
Two types of speciation (allopatric and sympatric)

Question 15

different rates of speciation

Answer 15

-gradualism= gradual accumulation of small changes over long time

-punctuated equilibrium= rapid bursts of change mixed with long periods of little or no change

Question 16

types of reproductive isolation

Answer 16

-geographical, temporal and behavioral

ALL result in two populations facing different selective pressures and will change

Question 17

example of geographical isolation

Answer 17

the convo river that is a physical barrier and prevents two ape populations from interbreeding. North has chimps, south has bonbos

Question 18

allopatric speciation

Answer 18

physical barrier that divides population

(geographical isolation)

Question 19

sympatric isolation

Answer 19

speciation occurs without physical barriers
(temporal or behavioral isolation)

temporal=incompatible time frames that prevent reproduction

behavioral=population developing behaviors that isolate them

Question 20

divergent evolution

Answer 20

-common ancestor
-homologous structures

Question 21

what is adaptive radiation

Answer 21

-outcome of divergent evolution
-allows closely related species to coexist without competing
-source of biodiversity

Question 22

courtship behavior preventing hybridization

Answer 22

the behaviors exhibited by animals to attract a mate of the same species

These behaviors are crucial in preventing hybridization,

Question 23

what is a polyploid organism

Answer 23

SPECIATION EVENT
an “accident” during cell division results in full extra sets of chromosomes

happens when chromosomes duplicate but cell does not divide
-More common in plants
-Triploid (3n), Tetraploid (4n), etc.
ABRUPT SPECIATION

Question 24

autopolyploid

Answer 24

organism that has more than two complete sets of chromosomes, all of which come from the same species.

Question 25

allotetraploids

Answer 25

Allotetraploids are organisms that have four sets of chromosomes derived from two different species. This type of polyploidy occurs when two different species hybridize and then undergo chromosome duplication, resulting in an organism with two sets of chromosomes from each of the parent species.

-can only interbreed with other allotetraploids

Question 26

convergent evolution

Answer 26

independently evolve similar traits as a result of adapting to similar environments or ecological niches.

Question 27

why analogous structures are not evidence for evolution

Answer 27

Analogous structures indicate that two species have evolved in response to similar selection pressures and do not indicate recent shared ancestry.