Evolution Flashcards
Theory
Explanation, supported by observations/ experiments
Used to explain related occurrences
Evolutional theory
Gradual CHANGE in a POPULATION over TIME
Trends shown by evolution
Organisms change over time
Life evolved from SIMPLE to COMPLEX forms
Life went form UNICELLULAR to MULTICELLULAR
Misconceptions of evolution
- only the strong will survive
- survival of the FITTEST (not always strength) FIT = ADAPTED - humans evolved from apes
- humans and apes evolved from a COMMON ANCESTOR - organisms change bc they need to
- populations change due to VARIATION passed on genetically from one generation to the next
Lamarack was WRONG
You can’t pass on traits you acquire during your lifetime
Lamarack’s law of use and disuse
The more an animal uses a certain part of his body, the stronger/ more developed that part of its body becomes
Lamarck’s inheritance of acquired characteristics
If you develop a characteristic during your life you can pass it of to your offspring
According to Lamarck
Ancestors of giraffes short necks, as food decreased they stretched their necks, necks became longer, long necks passed on to offspring
Charles Darwin was RIGHT, his theory:
Sailed to SA, studied Galapagos finches
Overproduction–Competition–Variation–Adaptations–Natural selection–Speciation
Natural selection
Organisms with favorable variations survive/produce more offspring than less well-adapted organisms
Survival of the fittest
Speciation
Formation of a new species
Time frame; millions of years
Darwin’s finches
Evolved bc limited niches
Niche= role in environment / how they get their food
Speciation
How fast does evolution occur?
Gradualism (Darwin's theory, gradual changes, millions of years) Vs. Punctuated equilibrium (rapid evolution in a short interval, supported by fossils)
So environmental changes always cause evolution?
NO:
Times when there is NO SELECTION means that the organisms’ traits are still fit for the environment (already adapt)
Organisms that don’t resemble their ancestors?
= DRASTIC CHANGE IN ENVIRONMENT
Ex: elephants
Survival of the fittest
=Natural selection
The ENVIRONMENT selects individuals with the best traits
Sources of Variation
Sexual Reproduction (the one that's more fun) : meiosis (crossing over) and fertilization, new genes produced each time, Asexual Reproduction (not as fun): mutation, random (change in genetic info)
Multicellular organisms: mutation: rare/random has to be in GAMETES to go to offspring and sexual repro
Unicellular organisms: mutation only (they don’t have fun)
Examples of Adaptations that = best fit
Camouflage, mimicry, warning coloration (poisonous)
Types of Camouflage
Cryptic coloration (checkered fish) Disruptive coloration (zebra) Counter shading (squirrel)
Modern day evolutionary theory
Darwin’s theory + knowledge on genetics
Results of genetic variation
- Structural change (thick furred polar bears)
- Functional change (electric eel, poisonous snake, antibiotic resistant bacteria, digesting certain foods)
- Behavioral change (nocturnal animals, firefly blinking, octopus)
Isolation
Anything preventing two groups WITHIN A SPECIES form interbreeding
Types of Isolation
Geographic isolation (natural barrier: mountains, river, lava)
Reproductive isolation (loss in the ability to interbreed, diff in courtship behavior -ex the dance- and mating times)
Species
Organisms
Share characteristics
Can mate/ produce offspring
Isolation often leads to speciation
Adaptive radiation
=Darwin’s fiches
=Divergent evolution
One species evolved into several diff species each having their own NICHE (role)
Convergent evolution
Organisms that are non related develop similar characteristics and look alike
Koala (marsupial) an bears
Variation vs no variation
Variation (sex + mutations) + change in environment = evolution (ex:horses)
No variation + change in environment = endangered / extinction (ex:panda bears)
IMPORTANT
⬆️variation= ⬆️survival
⬇️variation= ⬆️ extinction
You CANT develop a trait that you NEED, you either have it or you don’t
Supporting evidence of evolution
Comparative anatomy (homologous analogous vestigial structures), comparative embryology and comparative biochem
Comparative anatomy
The study of structural similarities and diff among living species
Homologous structures
SAME STRUCTURE and embryonic development, DIFF FUNCTION
Ex: human arm, whale fin, cat leg, bat wing, bird wing
Shows that organisms are adapted to diff environments bc they’re being used for diff things (diff niches)
Analogous structures
SAME FUNCTION DIFF STRUCTURE
Ex: bird and insect wings
Shows that they have a similar niche/environment but a DIFF COMMON ANCESTOR
Vestigial structures
Remnants of a structure that was FUNCTIONAL in ANCESTRAL FORM
more than 100 in humans
Tail bone, appendix, wisdom teeth, muscles with nose and ears
Comparative embryology
Similarities during the earliest stage of development
*Common Ancestry
Comparative biochem
Similar DNA, RNA and protein like enzymes
MOST RELIABLE
Antibiotic resistance
Antibiotics treat bacteria
Natural variation=ability to resist antibiotic
Variation= gene carried on by bacteria
Least resistant bacteria die 1st
Stoping antibiotic=greater proportion resistant
Pop of resistant⬆️
Diff antibiotic requires
Preventing antibiotic resistance
Avoid using antibiotics unnecessarily
Follow prescription : finish taking it
Use the most specific antibiotic possible
Population
Same species, same time, same place
Population Genetics
The study in the changes in the genetic makeup of a population
GENE POOL
All the alleles in the individual that make up a population at any given time
“Reservoir” of genes for next generation
Where genetic variation is stored
Shift in the gene pool
= evolution
Allelic Frequency
How often can certain genes be expressed in a gene pool Mathematic formula (%)
Hardy-Weinberg
NON EVOLVING
Hardy-Weinberg theory describes a non evolving pop, pop @ equilibrium
Generation after generation, gene pool stays the same
Hardy-Weinberg Equation
Each variable represents a diff type of allele
Need page 18 and 19 in pkt
Look at those pages in packet
Need page 18 and 19 in pkt
Look at those pages in packet
