A4.1 Flashcards
Evolution and speciation
What is evolution?
the development of new types of living organisms from pre-existing types by the accumulation of genetic differences over many generations through natural selection and chance variations.
What was Jean baptiste Lamarck’s theory
all the physical changes occurring in an individual during its lifetime can be inherited by its offspring.
What is change through use and disuses?
part of lamarck’s theory where the organs used more frequently develop while the ones not used much are lost in succeeding generations. An example would be the giraffs long neck to eat leaves from tall trees.
What is inheritance of acquired characters?
part of Lamarck’s theory where if an individual acquires certain characteristics they will be passed on to its offspring. An example of this is a blacksmith who has strong arms will have children whos muscles develop faster.
What is effect of environment and new needs?
part of lamarck’s theory where the environment influences all organisms and any changes in it would result in a change with the organisms.
What was Darwin’s theory of evolution?
Variation in population leads to selection pressures which enables organisms better adapted to the environment to survive and pass this advantage on to future generations.
What did DNA do and why?
confirmed Darwins theory of evolution because variation is caused by random mutations in the DNA which if caused in reproductive cells can be passed on to future generations.
What do modern genetics show?
acquired biological characters cannot be inherited unless they change the organisms DNA.
What is epigenetics?
the study of heritable changes in gene activity that are not caused by changes in the base DNA sequence and aren’t long-term
What do base sequences in DNA or RNA and amino acid sequences in proteins show?
It is possible to measure the relatedness of different groups of organisms by the amount of difference between specific molecules such as DNA, proteins and enzyme systems. This is because particular organisms share a common ancestor.
What is evidence for selective breeding of domesticated animals and crop plants?
Artificial selection is a human influenced process that specifically picks out the most useful progeny and breeds that to show genetic change.
What are homologous structures?
The body structures of organisms that appear fundamentally similar
What is classification based on homologous structures called?
Natural classification or phylogenetic classification since it is based on similarities and differences that are due to close relationships between organisms because they share common ancestors.
What are analogous structures?
Structures with similar functions but fundamentally different origins.
What is classification based on analogous structures called?
artificial classification
