Evolution Flashcards
How Long Ago Did the First Mammals Appear on Earth?
200 MYA
Three Common Traits of Mammals
1) Reproduce
2) Breath air
3) Warm blooded
Fitness
The relative ability of an individual or population to survive, reproduce, and pass on genes
Anagenesis
A pattern of evolution where there is no branching of the phylogenetic tree
Cladogenesis
A pattern of evolution where there is a branching from the original species on the phylogenetic tree
Anagenesis and Cladogenesis Both Result In
Forming a new species
Evolution
The process of change over time
Natural Selection
Organisms that are best adapted to the environment survive and reproduce more than others
Four Steps to Natural Selection
1) Overproduction
2) Variation
3) Competition
4) Selection
Overproduction
Each species produces more offspring than can survive
Variation
Individuals have the unique combination of inherited traits
Competition
Individuals keep for limited resources including food, water, space, mates, or staying alive
Selection
The individuals with the best traits/adaptions will survive and have the opportunity to pass its traits to its offspring
Adaption
An inherited trait that increases an organism’s chance of survival
Descent with Modification
Each living species had descended, with changes, from other species over time
Common Descent
All living organisms are related
Absolute/Radiometric Dating
Looking at the radioactive decay of the atoms in the fossils or Earth around it to determine an exact age
Archaeopyterx
Missing link between reptiles and birds
Vestige Organs
“Leftover” traces of evolution that serve no purpose
Embryology
Embryos of all vertebrates are very similar early on
Biochemistry
DNA with more similar sequences suggest species are more closely related
Microevolution
Evolutionary changes within a small group of organisms or species over a slow time
Macroevolution
Major changes among species occurring over a long period of time
Evolution Occurs When
Various pressures drive change and good traits build up in a population over many generations while bad traits are eliminated over time
Order of Evolution
Variation to pressure to selection to time
Three Natural Pressures
Resource availability, environmental conditions, and biological factors
Resource Availability
Presence of sufficient food, habitat, and mates
Environmental Conditions
Temperature, weather conditions, or geographical access
Biological Factors
Predators and pathogens (diseases)
Intentional Artificial Pressures
Humans select variants, known as selective breeding
Unintentional Artificial Pressures
Overuse of antibiotics creating antibiotic resistant bacteria, pollution
Directional Selection
Shifts the range of variation in traits in one direction
Stabilizing Selection
Favors intermediate forms of a trait
Disruptive Selection
Favors forms of a trait at the extremes of a range
Speciation
The formation of new and distinct species caused by reproductive isolation
Geographical Isolation
A physical Barries separating two groups of a population
Behavioral Isolation
Two populations are capable of breeding but are isolated by differences in courtship rituals or other behaviors associated with mating
Temporal Isolation
Species become different by reproducing at different times
Taxonomy
The science of classification
Order of Taxonomy
Kingdom, phylum, class, order, family, genus, species
Eubacteria
Unicellular, cell wall of peptidoglycan, prokaryotic, heterotrophic, autotrophic, photosynthesis
Archaebacteria
Unicellular, cell wall with no peptidoglycan, prokaryotic, heterotrophic, autotrophic, photosynthesis
Protista
Unicellular/some multicellular, eukaryotic, autotrophic, heterotrophic
Fungi
Multicellular, eukaryotic, cell wall with chitin, heterotrophic, decomposers
Plantae
Multicellular, eukaryotic, cell wall with cellulose, non-moving, autotrophic, photosynthesis
Animalia
Multicellular, eukaryotic, mobile, heterotrophic
Three Domains
Bacteria, archaea, eukarya
Scientific Names
Binomial nomenclature, genus and species
Autotrophic
Makes its own food
Heterotrophic
An organism eating other organisms
Sexual Selection
Natural selection arising through preference by one sex for certain characteristics in individuals of the other sex
Punctuated Equilibrium
The idea that evolution occurs in spurts instead of following a slow and steady path
Genetic Drift
The change in frequency of an existing gene variant in the population due to random chance
Hardy-Weinberg
A principle stating that the genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors
Order of Human Evolution
First bipedalism and then larger frontal lobe
Mammals
Appeared 220 MYA and have body temperature control, four chambered hearts, cerebral cortex development
Primates
65 MYA and have binocular vision, rotating shoulder joints, and prehensile tail. Two types are prosimians and arthropods
Hominids
Opposable thumb, bipedal locomotion, and larger brain case
Bottleneck
Population bottlenecks occur when a population’s size is reduced for at least one generation
Founder effect
A founder effect occurs when a new colony is started by a few members of the original population
