B15 Flashcards
why did people not believe in the theory of evolution
people thought that God created everything and the Earth was only a couple thousand years old
what is Darwins theory of evolution
the theory of evolution by natural selection
what observations was Drawins theory based on
- individual organisms in a species showed wide range of variation for a characteristics
- individuals with characteristics which are more suited to the environment are more likely to breed successfuly
- the characteristics which enabled the individulal to survive were passed onto the next generation
what did Alfred Russel Wallace do
he also created the theory of evolution by natural selection which caused Drawin to publish his findings in the next year (1859) and Wallace and Darwin also published joint writings in 1858. Afterwards Wallace worked worldwide to find evidence for this theory. He also created the theory of speciation
what is speciation
the process in which a new species is formed
what was Darwin’s book called
On the Origin of Species
why was there a lot of controversy on Darwins’ theory
- there was not a lot of evidence
- it challenged the ides that God created the world and all the species
- the mechanism of natural selection was discovered 50 years later
what were other evolutionary theories which conflicted the theory of evolution by natural selection
- the creationist theory
- the theory of intelligent design
how does the creationist theory work
that each living thing was created seperately and did not evolve. the time gap in fossils worked as evidence against evolution
what is the theory of intelligent design
that complex structures like DNA and mitochondria are far too complicated to have evolved over time and so must have been placed by a higher order of beings
what was Lamarck theory of evolution
the theory of inheritance of aquired characteristics and it went like this:
organisms changed throughout their lives because the organism wants too and these changes can be passed on to the next generation and organs which weren’t used will eventually disappear
what evidence did Darwin collect which made his theory be accepted in the future
- there is much variation in species
- only the ones which are most adapted will survive
- those who survive will pass on their genes and the rest will become extinct
- more offspring are born thant the environment can handle
how has the gene theory evolved
mid 1800s - gregor Mendell - inheritance of characteristics is determined by ‘units’ which are passed on
laste 1800s - chromosomes were observed during cell divison
early 1900s - chromosomes and Mendell’s ‘units’ behaved similarly - idea that genes were located in chromosomes
Mid 1900s - Watson, Crick, Franklin - structure of DNA and gene function was worked out
what are some evidence for evolution
- fossils
- study of antibiotic resistance in bacteria
how do bacteria become antibiotic resistant
bacteria evolve rapidly as they reproduce at rapid rates. mutations cause new strains in bacteria to be produced. some of these strains are resistant to antibiotics which means they survive and reproduce which means the resistant strain bacteria will spread as people aren’t immune to it and there is no effective cure for it
what can we do to reduce the rate of development of antibiotic resitance in bacteria
- doctors shouln’t prescirbe antibiotics for non serious or viral infections
- patients must complete the course of antibiotics so all are killed and none survive to become resistant
- resist the use of antibiotics in agriculture
how does speciation occur
1- a population gets isolated forming two groups cretaing 2 different gene pools
2- the 2 populations live in seperate conditions like climarte, food/water availability and new prey/predators
3- natural selection takes place where the most adapted survive and the rest die off. this causes change of characteristics. the longer the 2 populations are seperated the more different they become
4- eventually the 2 groups will become so different that they will no longer be able to breed to produce fertile offspring
what are some examples of barriers in speciation
- geographical barriers like seas and mountains
- physical barriers like roads
- behavior barriers like mating calls
- reproduction barriers like different mating times
what are some reasons for speciation
- geographical isolation
- ecological isolation
- temperal isolation
what are 3 ways fossils can be made
- parts of organisms have not decayed
- conditions for decay are absent
- preserved traces of organisms like footprints
how do fossils support Darwins theory of evolution
fossils of the simpler organisms are found in older rocks and more complex organisms are found in the newer rocks which show life forms gradually evolved
what is extinction
when there is no living individuals of an organism
why might a species become extinct
- new predators
- new diseases
- competition between animals leading to a mutation giving one species an advantage
- environmental change
- catastrophical event
- habitat destruction
what is fossil record
the study of the number and placement of fossils in an area
why are studying fossils important
- similarities and difference between modern and oldern organisms
- can suggest what a habitat was like
- shows evolution over time
how has the horse evolved
1- 4 toed to run on soft ground
2- lost 1 toe for moving faster on dry ground
3- middle toe turned to hoof to run faster
4- other toes lost as only hoof is only used
5- single hoof bigger to run on hard ground
what is classification
the organisation of living organisms into groups according to their similarities
why is classification important
- it helps to understand how different groups of organisms are related to each other
- it helps us to recognise biodiversity in the world
- gives scientists a common language to talk in
what are the 7 taxons/classes
Kingdom, Phylum, Class, Order, Family, Genus, Species
what did Linnaeus come up with
the binomial system where an organisms’ scientific name is based on its’ genus and species name e.g panthera leo = lion
what is a Mnemonic to help remember the taxons
King
Penguins
Climb
Over
Frozen
Grassy
Slopes
what are the 5 kingdoms
- fungi
- animalia
- plantae
- prokaryote
- protoctists
what did Carl Woese do?
discovered a new category of organisms called anarchae which were similar to bacteria but different as they lacked some RNA sequences which were core characteristics of bacteria
how did Woese class the organisms
he did it by having 3 main divisions:
- anarchaea
- prokaryota
- eucarya
