×

Hello! Socratic's Terms of Service and Privacy Policy have been updated, which will be automatically effective on October 6, 2018. Please contact hello@socratic.com with any questions.

Species

Key Questions

  • There are different ways that species can adapt to their environments. The genome of living organisms are the basis that allows them to modify previous features related to anatomo-physiological and behavioral characteristics that were typical and common to the original environment, in which these species evolved.

    For example, imagine a normal white person consistently exposed to the sun. The higher and constant stimulus provided by the new environment (i.e. larger amount of radiation) forces the organism to produce more melanin, the related skin and tissue protein which protect the respective tissues and body from excessive incoming and dangerous sunlight. So, there's a tendency to produce more and more melanin, but its production is limited to the genetic capacity to response on this phenomena. A person who have albinism #"could not"# response in these ways, because there's #"NO"# genetic basis to produce melanin!

    Also, you could hypothesize living beings fitting low air moisture and pressure, different average temperatures, soil constitution, concentration of solved oxigen in water or atmosphere, and so on. The response generated varies, comparatively, on the driving forces of the biotic and abiotic environmental pressure (weak, moderate or strong) and the own capacity to produce immediate responses to the new facing stimulus. That kind of immediate and specific response is called #"acclimatization"#, and it's related to the phenotypic plasticity of the organism.

    #"Adaptation"# is, by itself definition, related to the #"evolution"# of new genetic traits on the genome of some population or species, giving them new abilities to response positively to diverse environmental stimulus. Thus, some species will only adapt to new conditions if their modified genome evolve in this new environment, fixing the new aleles/genes related to that kind of phenotype response.

  • Answer:

    Humans ( Homo sapiens ), moose ( Alces laces ), black bears ( Ursus americans ), jack pines ( Pinus banksiana ) are all examples of different species.

    Explanation:

    There are multiple definitions of what exactly is a species. Thus, there are instances in which one species is considered two species by a different group of scientists, and there are instances when determining if something is a new species is challenging, for example, in hybrid zones.

    Examples of widely recognized species include

    The Brazil nut tree (Bertholletia excelsa )
    http://www.caminoverde.org/resources/tree-database/324
    The whale shark (Rhincodon typus)
    http://animals.nationalgeographic.com/animals/fish/whale-shark/

    The Australian ant (Nothomyrmecia macrops )
    http://www.arkive.org/australian-ant/nothomyrmecia-macrops/

    Staghorn coral (Astreopora expansa)
    http://coral.aims.gov.au/factsheet.jsp?speciesCode=0094

    There are many more species yet to be discovered, particularly insects, plants, and other non-mammal species.

    http://www.economist.com/blogs/dailychart/2011/08/species

    You can read about a tree of life for 2.3 million species here .

  • Answer:

    There are multiple definitions of the term "species." See detailed answer below.

    Explanation:

    In it's simplest term, species may refer to a group of individuals that interbred with one another and produce offspring that are not sterile.

    However, this definition can be too simplistic at times. For example, how do we know what a species is for organisms that existed millions of years ago? What about species that are asexual or that are hybrids?

    There are multiple ways to define species and each is slightly different:

    Biological species concept -This is the most commonly used definition. Individuals able to interbred with one another and produce viable offspring or a gene pool that is not exchanging genes with other gene pools. For example, a lion and a tiger can interbred and produce an offspring, but the offspring of the lion and tiger is sterile and cannot reproduce. Thus, lions and tigers are not the same species.

    Morphological species concept -a species is defined by its morphology. Individuals with similar traits or phenotypes are grouped together. For example, in the image below, individuals are grouped into species mainly based on the overall body size. Different phenotypes do not always accurately reflect separations (i.e. albino offspring). This definition is often used for extinct species.

    Phylogenetic species concept -individuals that represent the smallest part of an evolutionary tree or phylogeny are a species. This concept works well with species that have recently diverged and it works with asexual species.

    Ecological species concept -different species have different ecological niches. This concept allows for hybrids and asexual organisms. Species are defined not by reproductive isolation but by their adaptations to select ecological niches.

    Genetic species - defines a species as individuals with similar DNA.

    Recognition species concept -individuals that recognize each other as possible mates are of the same species.

Questions