evolution Flashcards
what is evolution?
the gradual changes in populations of organisms from their ancestors over time.
what is the theory of evolution?
attempts to explain how living organisms similar in molecular structure are so different in form and function
main points of Lamark’s theory of acquired characteristics
- changes in the environment caused organisms to need or not to need certain structures
-if a organisms doesnt need a part it will dissapear
-when a organisms needs an adaption it will adapt - it change is beneficial parents will pass it down
-INVALID
what is Darwins theory of natural selection
caused by factors,
VARIATION, no 2 organisms are exactly alike, variations are passed through heretity
OVERPRODUCTION, all organisms that produce more offspring that can survive to reproduce
COMPETITION, over poulation causes organisms of the same species and organisms of different species to compete for resources
NATURAL SELECTION, organisms with variations that allow them to out compete others will survive and reproduce while others die out.
what are sources of variations
variations can PHYSIOLOGICAL, STRUCTURAL, or BEHAVIORAL
MUTATIONS, all genetic variations originated from mutations and got passed through generations, if it is good bad or neutral will depend on reproductive success, recessive traits, if environment changes it becomes a adaption.
RECOMBINATIONS, during crossing over causes different genetic variations.
what is indirect evidence of evolution
ANALOMICAL STRUCTURES, homologous structures, same structure diff function, analogous similar function different structure
VESTICAL ORGANS, body part with no apparent use
EMBRYOLOGICAL, animals appear same in embryo
BIOCHEMICAL, analysis indicating organisms are similar in molecular structure
ARTIFICIAL, breeding selected organisms to get selected traits.
BIOGEOGRAPHIC,
TYPES OF BIOGEOGRAHPIC EVOLUTION
DIVERGENT, change of organism from common ancestor into new species
PARALLEL, 2 relative species evolve in same way over period of time
COEVOLUTION, evolution of one species responding to another
CONVERGENT, evolution of 2 different species becomes more similar because of environment
examples of direct evidence of evolution
extinct animals resembling current one
- carbon dating fossils
-fossil records
what are the types of evolution
STABILIZING, favors the middle ground heterozygous
DIRECTIONAL, favors phenotypes at one extreme
DISRUPTIVE, FAVOURS BOTH EXTREMES
3 CHARACTERISTICS OF EVOLUTION
- evolutionary change involves the change of a population not a individual
- a single evolutionary event includes few characteristics
- must be a valid reason for change
factors effecting natural selection
GENETIC DRIFT, change in gene pool due to chances occurance resulting in loss of traits
GENE FLOW, movement of population from one area to another
ISOLATION, group becomes separated and will adapt on its own
a) physical barrier
b) reproductive
what are the origins of humans and some unique traits
originate in east africa
Australopithecus afarensis
oldest fossil 3.15 million years ago
both hominid and ape structure
humans didn’t evolve from apes but both evolved from a common ancestor
unique traits, posture is upright, bipedal motion, opposable thumbs, eye infront of skull, cerebral cortex far more developed
what is the theory of continental drift
that at one point all continents were joined together and eventually split apart.
what is taxonomy,
classification of living organisms
who created binomial nomenclature
Linnaeus uses two words to classify a organism, give the genus name followed by the species name
Homo sapien
