Chap 13-14 Flashcards
What is evolution
Process where modern organisms have descended from ancient organisms
What is diversity of life
Planet housing variety living organisms
What is fitness
Physical traits & behaviours enable organisms to survive/ reproduce in their environment
What is common descent
Species descended from common ancestors
What are Darwin’s 3 theories
- Modern organisms produced by process of evolution (process of change in species )
- Argued each organism comes from pre existing organisms (species descended from other species)
- Fitness happens through adaptation
What is adaptation
Inherited characteristics that increase an organism fitness for survival
What is an adaptation ex
Long neck / legs of giraffe allow giraffe to eat from higher trees
What are fossils
Preserved remains of ancient organisms
What did James Hutton say
Rocks mountains valley’s gradually changed because of rain, heat, force, cold, volcanoes, & natural forces
What did Charles Lyell argue
1830, argued scientists should explain past events in terms of events process they could observe
What is relative dating
Technique used by scientists to determine age of fossil relative to other fossilsin different layers
What is half life
Length of time required for half radioactive atoms in sample decay
What is Radioactive dating
Measuring rates of decay of radioactive materials to determine how long ago an event occurred or an organism lived
Where are fossils found
Sedimentary rocks
What is sedimentary rocks
Rocks formed when exposed to heat, rain, & cold breaks downexisting rocks into small sand, clay slit particles
What is chany process
Fossil records not complete because some organims leave proper fossils
What is paleontologist
Scientists who study fossils
Fossil records
Representation of preserved collective history on Earths organisms
What are Hox cluster
Group of genes establishing basic pattern of organs & structure from head to tail
What is Homogolous structures
Structures which meet different needs but develop from same body parts
What do organisms use to carry genetic info
DNA DNA carries info from one generation to another
What is Darwin’s conclusion
Living organisms evolved through gradual modification of earlier forms
What is evolution theory
Foundation on which biological science is built
What 3 Lamark assumptions are wrong
- A Desire to Change: organisms change because they have an urge to better themselves
- Use & Disuse: Changer occurred because organisms could alter their shape by using their bodies in different ways. Organs could increase in size or shape depending on the need by the organism
- Passing on Acquired Traits: Acquired characteristics were inherited.He thought, if animalsacquired a body structure it could be passed down to it’s offspring
What 3 Lamarck assumptions are wrong
- A Desire to Change: organisms change because they have an urge to better themselves
- Use & Disuse: Changer occurred because organisms could alter their shape by using their bodies in different ways. Organs could increase in size or shape depending on the need by the organism
- Passing on Acquired Traits: Acquired characteristics were inherited.He thought, if animals acquired a body structure it could be passed down to it’s offspring
What can be passed from one gen to the next?
Only genes/ changes in genes can can be passed from one parent to the other,
What are the ideas that shaped Darwin’s Theory
- The Influence of Geology (Lyell): After reading Principle’s of Geology Darwin was convinced that Earth was much older than most people believed back then
- Artificial Selection (farmers): Farmers altered/ improved their crops & livestock through breeding programs
- Population Control (Malthus): Many more offspring are produced that can possibly survive (only the best survive)
- Malthus Doctrine: famine,disease & war killed the human population. Darwin realised only applied to animals & plants
What is artificial selection
Intervention of humans ensures only individuals with better traits produce offsprings
What is natural selection
Process in nature that results in the most fit organisms producing off springs
How is natural selection different from artificial selection
- Happens over much longer periods of time
- Lacks control/ direction
What is Darwin’s reasoning
Wild animals/ plants show variations
Birthrates are high
resources/ life necessities forced organism’s into constant “ struggle for existence” & Against each other/ environment
Darwin’s principle “Survival of the Fittest”
Individual organisms whose characteristic are well-suited to environment survive
Individual organisms whose characteristic aren’t well-suited to environment die or leave few off springs
Difference between Darwin’s & Lamarck theory of evolution
Lamarck believed that organisms could acquire characteristics during their lifetime that they could pass down to their offspring, but Darwin did not believe these traits could be passed down.
What are genes
Carriers of inheritable traits & source of random variations
What are the reasons for variation
Mutation
Shuffling of chromosomes during meiosis
Variation doesn’t happen because organisms need/ want to evolve (Lamarck’s theory). Organisms can’t control DNA changes
What is a phenotype
Physical & behavioural characteristics produced by interactions of genotypes & environment
ex: Height
Color of skin/hair/eyes
Shape of noses/ lips
Amount of body hairs
What is population
Collection of individuals of the same species in a given area whose members can breed
What is gene pool
Members of a population can interbreed & they / offspring share common genes
Each gene pool contains allele or forms of certain gene at given points on chromosomes
What is an allele
form of a certain gene at a given point on chromosomes
what is relative frequency
Sexual reproduction alone does not change the relative frequency of all alleles in a population, just as shuffling & dealing cards doesn’t change the relative # of aces, kings, fours etc
What is new evolution def
Increase in the relative frequencies of all alleles in the gene pool of a population
What is evolutionary fitness
Success an organism has in passing on it’s genes to offsprings
What is adaptation
Genetic characteristics that increases fitness
What is interbreeding
Share common gene pool
Genetic change in one individual can spread through population
If changes increases fitness, gene will eventually be found in many individuals in population
What is speciation
process in which new species evolve from old species
What is niche
an organism “profession” & the place in which it lives
No 2 species can live in same niche for long periods of time
what is Reproductive Isolation
separation of populations so they don’t interbreed
How does reproductive isolation occur
Geographic barrier
Difference in courtship behaviours
Difference in fertile periods
Steps to Darwin’s finch theory
- Founding Fathers & Mother: ancestral Finches arrived at island A & survived & reproduced
- Separation of populations: some birds crossed from A to B became isolated
- Changes in Gene Pool: Populations on each island adapted to the needs of their environment. ( A = small seeds B = large seeds )
- Reproductive Isolation: If a few birds from A crossed to B they can’t breed with one another - separate species
Finches prefer to reproduce birds with the same beak size they do - Sharing Same island: the fate of 2 species on B
What is (divergent evolution)
Process by which different organisms having common ancestors develop different traits or characteristics to adapt to the changing environmental conditions and needs
what is adaptive radiation
Evolutionary process by which many species originate from one species in an area and change to different species
What is convergent evolution
The process where distantly related organisms independently evolve similar traits to adapt to similar necessities.
Difference between convergent & divergent evolution
convergent evolution involves unrelated species that develop similar characteristics over time,
divergent evolution involves species with a common ancestor that change to become increasingly different over time.
What are analogous structures
Structures that are similar in appearance and function, but have different origins. Analogous structures are often produced by convergent evolution. Examples the wings of butterflies, birds, and bats are all made of different things but perform the same function: flying
What is genetic drift
Random change in frequency of gene
what is homologous structures
similar physical features in organisms that share a common ancestor, but the features serve completely different functions.
Ex; limbs of humans, cats
Difference between homologous structure & analogous structure
Homologous structures share a similar embryonic origin; analogous organs have a similar function.
What is gradualism
theory that evolutionary change happens slowly & gradually
What is equilibrium
Animals that don’t change very much
What is punctuated equilibrium
theory that states that evolution occurs primarily through short bursts of intense speciation, followed by lengthy periods of stasis or equilibrium
What is mutation
Any change in the DNA sequence of a cell.
Difference between punctuated equilibrium & gradualism
Gradualism is the concept that large changes in species are actually the culmination of very small changes that build up over time. Punctuated equilibrium states that changes in species take place over a relatively short amount of time “punctuating” the long periods of equilibrium
What is mass extinction
When species vanish faster than being replaced
How are new species created
speciation
