CH.3-Evidence/Darwin principle Flashcards
What are the 3 observations Darwin wished to explain?
1) Adaptation
2) Connectivity (shared characteristics among living organisms)
3) Diversity of life
What is Darwin’s Theory?
Vertical descent with modification (mutation) = Evolution ==> Living organisms get better adapted to environment over time by beneficial genetic mutations
How do living organisms get better adapted?
Over many generations, they gain beneficial genetic mutations
What is Darwin’s proposed mechanism of evolution?
Natural Selection
What is natural selection?
Force that drives evolution by causing individuals with advantageous genetic traits to survive and reproduce better than others
What is microevolution?
Small changes in genetic makeup of populations that may occur between generations
What is macroevolution?
Over long period of time, if population has enough genetic material it can become new species
What is a species?
Population/group of populations whose individuals can interbreed and produce offspring.
True or false? A species can interbreed with other such groups
False
Which philosopher used Scala Naturae?
Aristotle
What is Scala Naturae?
Nature has levels of complexity from simple to complex
What did Carolus Linnaeus believe in?
All species were created for a purpose. Proof how well they adapted in environments
Who were Darwin’s influencers?
George Cuvier: Studied fossils in sedimentary layers and conclusion of CATASTROPHISM
James Hutton & Charles Lyell: Didn’t believe in catastrophism ==> Believed that geological strata were deposited slowly over time ==> UNIFORMITARIANISM
Jean-Baptiste de Lamarck: Indiv organisms evolve with changing environment during lifetime
Thomas Malthus: Population growth is exponential but resources become limited ==> Competition
What was Lamarck’s 2 hypotheses?
1) Use & Disuse:
Body parts needed for survival get stronger while others deteriorate
2) Inheritance of acquired characteristics:
Can be passed down to next gen
Darwin spent time in Galapagos Island and observes many —
adaptations
What is an adaptation? What does it lead to?
Inherited traits of organisms that are beneficial to survival and reproductive success in environments ==> Leads to more offspring
What is Darwin’s view on history of life?
Multiple branches arise from common trunk (one original common ancestor)
Pre-Darwin, was a ladder or a tree?
Tree
What tool is used to understand the evolutionary relationship between organisms?
Phylogenetic tree
HOW does natural selection work? What does the environment do to the organisms living in it?
It puts certain pressures on them for survival
What are the ways pressures can be exerted by?
1) Physical environment
2) Living organisms they interact with
What are examples of physical environment pressures?
Weather, availability of resources
What are examples of interactions with other organisms pressure? The types of competition
Intraspecific competition: Between same species (mates, territories, food)
Interspecific: With other species (predator/prey, resources)
Is it a question of survival of the fittest?
No, those with better traits of survival have higher reproductive success/fitness (Reproductive fitness)
Natural selection can only happen if:
1) Members withing a population have variations in genetic characteristics
2) Environmental pressures to produce more offspring
3) Lots of time
What is genetic variation a result of?
Mutation
Genetic variation amongst individuals is increased through —
Sexual reproduction
Overproduction of offspring causes what between individuals?
Competition for resources
Natural selection acts upon —-, but the smallest level at which evolution occurs is the —- level.
individuals - population
What evidence supports the theory of evolution?
1) Direct observation of evolutionary change (microevolution)
2) Homology
3) Convergent evolution
4) Fossil record
5) Biogeography
Direct observation of evolutionary change: What is artificial selection?
When humans are the selective force determining favorable genetic traits
Selecting traits from wild animals to create domestic animals is what type of selection?
Artificial (humans)
Artificial VS Natural selection?
Artificial selection = humans are the external pressures (selects indiv to breed to find desirable trait)
Natural selection = environment/interactions is the pressure
What is homology?
Similarities resulting from common ancestry
At molecular level, how is homology represented?
Genetic material of all living organism (most) are written in same code
How does homology affect embryonic development?
Early stages of embryonic development, vertebrates look the same
How does homology affect vestigial structures? Examples?
Remnants of structures form ancestors (appendix, tail bone)
What is convergent evolution?
Evolution of similar characteristics but unrelated organisms (no shared ancestor) because of similar environmental pressure
Similar characteristics are called
Analogous
Shared ancestor is called
Homologous
How does biogeography affect evolution?
Living organisms are more related to other living organisms in same area
What is divergent evolution?
Separation and isolation of populations
