Exam – Evolution Flashcards
Scientists and Their Contributions to Evolution
George-Louis Leclerc
- Challenged the idea that life never changed, introduced first concepts of evolution
George Culver
- Catastrophism
- Thought that the earth had many catastrophes which killed lots of species, often on the edges of rock boundaries (tectonic plates)
Charles Lyell
- Uniformatism
- Said that geological process have always been happening at the same, very slow rate.
Jean-Baptiste Lamarck
- Inheritance
- Said that organisms adapt to the env. over time, but thought that aquired traits were passed down
- EX. Parent with burned hand scar would have child with scar too
Darwin & Wallace
- Evolution through natural selection
Natural Selection
Change that happens over many generations; surviving individuals pass their traits on to offspring
Selective Pressures
Env. conditions that select for certain traits and not others
Mimicry
A harmless species evolving to look like a harmful one to scare off predators
Species Variations
Structural, functional, or physiological differences between organisms
Evidence of Evolution
Paleontology
- Fossils; remains of an organism or evidence of its presence
Comparitive Anatomy
- Looking for structures that are similar between species
Embryology
- Similarites in embryo development between organims
Comparitive Biochem.
- Comparing DNA & amino acid base sequcences between organisms
Geographical Distribution
- Natural geographic distrubution of species on the earth
Paleontology
- Study of fossils & their age
- FOSSILS – Remains of an organism or evidence of its presence
- The deeper the fossil, the older
Behavioral Isolating Mechanism
PRE ZYGOTIC
- Behavior or routine that stops a species from breeding
- EX. Bird species having different mating calls
Habitat Isolating Mechanism
PRE ZYGOTIC
- When two species live in different habitats in the same general area
- Physically blocked from interacting
- EX. Fish and land bugs
Temporal Isolating Mechanism
PRE ZYGOTIC
- When species mate at different times or parts of the year, limiting interaction
- EX. tulips bloom in spring, roses bloom in mid summer
Mechanism Isolating Mechanism
PRE ZYGOTIC
- Closely related species who’s genital anatomy are phycially incompatible
- Common in insects
Gametic Isolating Mechanism
PRE ZYGOTIC
- Gamete is not able to survive in the harsh env. of the female’s reproductive tract
Hybrid Inviability
POST ZYGOTIC
- Genetic info is not compatible within the species
- Zygote is not able to undergo mitosis
Hybrid Sterility
POST ZYGOTIC
- When two species can mate & produce viable offspring
- Offspring are sterile, cannot do meiosis
Hybrid Breakdown
POST ZYGOTIC
- Two organisms are able to mate and produce viable & fertile offspring
- When hybrid offspring mate, their offspring are sterile & weak
Stabilizing Selection
- Natural selection that favours average pheotypes, doesn’t like extreme variations
- Reduces variaiton, improves adaptation of population to aspects of env. that remain constant
ex. bird egg size & number laid
Directional Selection
- Natural selection that favours phenotypes of one extreme over the other, or the average.
- Common during changes of the living env.
ex. more peppered moths being black during the industrial revolution due to soot, becoming white more often after anti-pollution laws
Disruptive Selection
- Natural selection that favours the extremes of a range of phenotypes rather than the average.
- No more average. Either extremely A trait or extremely B trait
ex. squirrels with long tails for balance, also ones with short tails to avoid being caught by predators
Artificial Selection
Selective pressure made by humans which force a population to change to different traits (usually on purpose)
Sexual Selection
When females in a species choose the most fit male (to make good offspring)
Non-random Mating
Mating where individuals are more likely to mate with individuals with certain genotypes/phenotypes
- Can cause inbreeding
Homologous Structures
Body parts in species that have the same evolutionary origin, but serve different purposes
Analagous Structures
Different structures that have a common purpose in unrelated species
Vestigial Structures
A structure that is a reduced version of one that was functional in previous generations
