Unit 2 - Evolution, Taxonomy Flashcards
Define evolution
any change in inheritable traits within a population across generations
define generation
a group of organisms born at the same time
population
a group of organisms living in the same place at the same time
variation
genetically different organisms that can be passed down through reproduction (eg: brown vs blue eyes)
what is the difference between evolution and genetics
evolution is the process of traits and organisms changing, genetics is the DNA and what is causing the changes
What are some conditions that must be met in order for a mutation to become a trait in the population?
They need to be able to survive through the environment - for a mutation to become a trait, it depends on if both parents have the trait. If the mutation is beneficial it will more likely be passed through generations, as it allows the population to thrive.
how do variations arise?
sexual reproduction: genetic info from each parent combining, combination of alleles produces new traits
mutations in genes: occur spontaneously, can have positive, negative or neutral effect on survival, must occur in the reproductive cells (germline)
define micro evolution
small scale changes occurring within a population
define macro evolution
large scale changes occurring within an entire species
what is a species
a group of organisms that can interbreed to produce viable offspring
what is speciation
the formation of a new species
what are the 3 main principles of Lamark’s theory of evolution
- all of the physical changes that occurred for an individual organism during their life are inherited by their offspring (organs that organisms stopped using would shrink)
- transmission of acquired characteristics (giraffe has long neck, offspring will have longer neck)
- Evolution by natural processes
what was the key knowledge that prevented Lamarck (and Darwin) from developing accurate theories
lack of knowledge of how traits were passed from parent to offspring: “genes” weren’t discovered yet and that they could pass information down - a key building block to prove why it occured
What are the key differences between Lamarck and Darwin’s theories
Lamarck: use & disuse, transmission of acquired characteristics, increasing complexity, no extinction
Darwin: variation, inheritance, differential survival, extinction
what is Darwin’s theory of evolution
Darwin believed that individuals were simply born with different traits and that these differences were mostly random. An example would be if a Giraffe was born with a long neck it would have a higher chance of survival as it could reach for more food and pass that gene to future generations.
what are similarities between the two theories
- life changed gradually over time and is still changing
- living things change to be better suited and adapted to their environments
- all organisms are related
what is Lamarck’s theory of evolution
a trait is developed/learned to meet the individuals needs in their lifetime
this trait is acquired and passed onto their offspring
*traits adapt to the environment
what are the 5 conditions for natural selection to occur (darwin)
- overproduction
- struggle for existence
- variation
- survival of the fittest
- speciation
elaborate: overproduction
the number of offspring produced by a species is greater then the number that can survive and reproduce
elaborate: struggle for existence
organisms of the same species (and other species) must compete for limited resources
elaborate: variation
differences among traits occur randomly in a population
*variations that become common are called adaptations - these change very little over time
elaborate: survival of the fittest
individuals with an advantageous trait survive and reproduce, increasing their numbers
*“selection” by nature
elaborate: speciation
over long periods of time, advantageous traits become more common and lead to the formation of a new species
what are 2 ways a new species can form
- transformation: gradual changes over time that produce a species that is more adapted then others
- divergence: a barrier prevents individuals from reproducing, so 2 or more populations form and become new species
does transformation or divergence increase diversity
divergence (parent species becomes 2, opposed to 1 species becoming another)
what are some barriers that cause speciation
- geographical (physical separation that divides a population)
- behavioral (mate selection based off different traits)
- mechanical
what are the 2 patterns of evolution
divergent and convergent
speciation occurs as a result of natural selection
divergent evolution
2 or more species share a common ancestor but the populations allele frequency changes (as a result, physical traits change)
(homologous traits)
convergent evolution
2 or more species from different ancestors become more similar in appearance or traits as they adapt to the same kind of environment
(analogous traits)
define allopatric speciation
geographic isolation - small group breaks away, or natural events like earthquakes, etc could happen.
define sympatric speciation
doesn’t require geographic isolation – separate behaviors or choices isolate them among their population
define homology
to have the same or simillar relation, relative position or structure
traits inherited by 2 different organisms from a common ancestor
define phylogeny
a family tree (shows relationships over much longer periods of time)
define morphology
the study of size shape and structure of animals plants and the relationships of their structures
what 3 criteria are used to determine whether a shared physical trait is a homology or analogy (convergent)?
- basic structure
- same development
- same relationships to other creatures
what is a homologous structure
species that inherited a physical structure from a common ancestor but each evolved a different function
what is an analogous structure
species that have different structures that perform the same function (different ancestors)
Eg: wing of bird versus wing of insect
what is a vestigial structure
inherited structures that are no longer needed - smaller and simpler then ancestral species
eg: human appendix, wisdom teeth, tailbones
what are some methods to investigate the phylogeny of organisms
- anatomy/morphology
- paleontology (fossil records, determine time, extinct species, however incomplete)
- molecular analysis (compare nucleic acid, more reliable, not easy to determine mutations between sequences)
- embryology (early developmental characteristics, reveals similarities,
what is taxonomy
a system to classify species
to assist in species identification, assign formal/consistent names, etc.
what is binomial nomenclature
an international system of naming species
two terms used to scientifically class a species of a living organism,
pt 1: Genus (captial, italic)
pt 2: species (lowercase, italic)
what are the 7 pieces in a taxonomy
kingdom
phylum
class
order
family
genus
species
what is a dichotomous key
a tool that allows the user to identify an organism (each step is a pair of statements)
