BIO 3051 EVOLUTION PATTERNS Flashcards
Adaptive radiation
Rapid evolution of ancestral (single) species into several lineages, each with their own unique adaptations
Co-evolution
A change in the genetic composition of one species in response to a genetic change in another species.
Two aspects of study of evolution
Patterns (products of evolution)
• adaptive radiation
• parallel
• co-evolution
Processes underlying these patterns
Key people involved in study of evolutionary biology
-Lamarack
-Malthus
-Darwin
-Wallace
Lamarack
-French naturalist
-species themselves had a role in determining their evolution
-e.g. giraffe obtains a long neck by striving to reach higher to get food
-characteristics developed in the life of indiv could be inherited by next gen.
-inheritance of acquired characteristics & was misleading
Malthus
-british economist
-essay on human populations
-showed that human population could increase in size exponentially if it wasn’t for limits to resources
-respurces such as food, shelter, build up of wastes degrading environment
-catastrophic collapse in population size
Darwin
-despite Malthus’ predictions of rapid increase, natural populations tend to remain at the same size
-most offspring must die before maturity
-lots of variation within a species
Wallace
-as environment changes, or species moves into different range, environment would select different characteristics so that the population would gradually change some of its characteristics
-about 8 million species alive on earth
Give evidence to support the theory of evolution as well as deductions .
Observation (evidence)
-indiv in a population have a great reproductive potential
-variation between inidv exist in all populations
-numbers of indiv in a population remain fairly constant
Deductions
-must be a struggle for existence between indiv in a population
-variation must underpin evolution
-in struggle for existence & survival those individuals showing features best adapted to their environment at that point in time must have a reproductive advantage and will therefore produce more offspring than less well-adapted individuals.
Phenotype is the result of an interaction between environment and gene expression
How is variation caused
By differences between individuals at genetic level
How is evolution made possible
Because of the differences between individuals in terms of the allele combinations they carry.
Fossil
-Preserved remains or traces of past life forms
-Important dating method to look into the past
-at least 10 000 years ago
-oldest fossil 3.4 billion years old
-preserve only parts, teeth, bones, calcium- or chitin-rich exoskeletons
Linnaeus taxonomy
-classified all organisms within a hierarchy
-at the top, living organisms are placed in one of three kingdoms
-archaea, bacteria and eukaryota
Phylogenetic tree of life
Explain the hierarchy of living organisms
-kingdoms
-classes
-orders
-families
-genera
Species
A group of individuals that interbreed and produce fertile offspring
Macro-evolution
Evolution on a larger time scale, such as thousands or millions of years.
Changes that happen at or above the species level.
Micro-evolution
The changes in allele frequencies that take place within a population. Micro-evolution tends to cover a small period of time such as about 100 years
Explain “evolution is descent with modification”
-charles darwin
-suggested all species alive today are descendants of ancestral species
-ancestors were different from the species alive because of different environments.
-would require for species to have different adaptations and different survival strategies
Adaptations
Inherited characteristics of organisms that enhance their survival and reproductive success in a specific environment at a specific point in time
Ancestral species
Species from which a number of new species are descended.
How are ancestral species vulnerable to mammalian predation
-strong body odor
-often live and nest on the ground
-may be slow-moving
-long-lived and breed slowly
-many bird species lost power of flight because there was no threat of predation on the ground.
Genetic vatiation and evolution
-for evolution to occur, genetic variation os needed
-changes have to be incorporated from one generation to the next
-need several generations for changes to show up in phenotype means that time plays an important part
Dating methods
-the direct and indirect methods used to determine the order of past events or age of fossil evidence
-DNA analysis
-protein analysis
-biogeography
Biogeography
The study of the distribution of species in geographic soace and through geological time.
Why would the fossil record be patchy.
-long periods of history, conditions for preserving fossils are unfavorable and there is no record.
-some places where there were many different forms of life, landscape was eroded away and wiped clean of fossil records.
-by pure chance that fossils become exposed
-small land mass, and varied habitats
-fossils are of a variety of forms & very few contain original plant or animal material
Petrified wood
Wood in which all the organic molecules, including DNA, have been replaced by minerals such as quartz
Give assumptions made when fossils are located in undisturbed rock formations
-any rocks found under the fossils are older than the fossils. Recording different depths, order of succession is revealed and is especially clear in sedimentary rocks because the layers were formed with new ones on top
-identifying similar fossils in seperated rock formations is used to decide which rock layers are of the same age.
Global geochronological scale
The overall international time scale.
-give relative time - order of events in relation to each other