Flashcards in Evolution Test Deck (50)
What did Hutton and Lyell help scientists recognize?
that Earth is many millions of years old, and the processes that changed Earth in the past are the same processes that operate in the present.
proposes that Earth is shaped by geological forces that took place over extremely long periods of time. He estimates Earth to be millions of years old.
In his essay on the Principle of Population, Malthus predicts that the human population will grow faster than the food and space needed to sustain it.
Lamarack publishes his hypotheses of the inheritance of acquired traits. The ideas are flawed, but he is one of the first to propose a mechanism explaining how organisms change over time.
Darwin sets sail on the H.M.S Beagle, voyage that will provide him with vast amounts of evidence leading to his theory of evolution
In the second and final volume of Principles of Geology, Lyell explains that processes occuring now have shaped Earth's geological features over long periods of time.
Wallace writes to Darwin, speculating on evolution by natural selection, based on his studies of the distribution of plants and animals.
Where did Darwin publish his ideas?
in his book On the Origin of Species
What did Lamarack propose?
that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime. These traits could then be passed on to their offspring. Over time, this process led to change in a species.
What did Malthus reason?
if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone.
-he noticed that the only forces that worked against this wee war, famine, and disease.
What is artificial selection?
nature provided the variation, and humans selected those variations that they found useful.
struggle for existence
means that members of each species compete regularly to obtain food, living space, and other necessities for life.
the ability of an individual to survive and reproduce in its specific environment,
any inherited charcteristic that increases an organism's chance of survival.
survival of the fittest
Individuals with characteristics that are notttt well suited to their environment-that is, with lower levels of fitness-either die or leave few offspring. Individuals that are better suited to their environment- that is, with adaptions that enable fitness-survive and reproduce more successfully.
What does natural selection result in?
in changes in the inherited characteristics of a population. These changes increase a species' fitness in its environment.
descent with modification
each living species has decsended, with changes, from other species over time.
all specie-living and extinct-were derived from common ancestors. Therefore, a single tree of life links all living things.
What did Darwin argue?
that living things have been evolving on Earth for millions of years. Evidence for this process could be found in the fossil record, the geographical distribution of living species, homologous structures of living organisms, and similarities in early development, or embrylogy.
structures that have different mature forms but develop from the same embryonic tissues
organ that serves no useful function in an organism
summary of darwin's theories:
-individual organisms differ, and some of this variation is heritable.
organisms produce more offspring than survive, and many that do survive do not reproduce,
-because more organisms are produced than survive, they compete for limited resources
-each unique organism has different advantages and disadvantages in the struggle for existence. Individuals best suited to their environment survive and reproduce most successfully. These organisms pass their heritable traits to their offspring. This process of natural selection causes species to change over time.
-Species alive today are descended with modification from ancestral species that lived in the distant past. This process, by which diverse specie evolved from common ancestors, unites all organisms into a single tree of life.
consists of all genes, including all the different alleles, that are present ina population
of an allele is the number of times that the allele occurs in the gene pool, compared with the number of times other alleles for the same gene occur.
what is evolution mean in genetic terms?
any change in the relative frequency of alleles in a population.
what are the two main sources of genetic variatin
mutations and the genetic shuffing that results from sexual reproduction
any change in a sequence of DNA
the number of phenotypes produced for a given trait depend on what?
how many genes control the trait
single gene trait
trait controlled by a single gene that has two alleles