Chapter 3: Evolutionary thought and theory Flashcards
3 Principles of science
- there is a real and knowable universe
- the universe operates according to understandable laws
- these laws are unchanging
4 Methods of science
- Create one or more testable hypotheses to explain observations or answer questions
- Test the hypothesis (or hypotheses)
- Accept, modify or reject the hypothesis
- Continually reevaluate the hypothesis as new data becomes available and new hypotheses are created
Hypothesis
must be testable, there must be some way to collect & analyze data to support or reject it
Theory
usually made up of multiple hypotheses and data that support the claim
6 Key concepts in evolutionary theory
Mutation, natural selection, sexual selection, gene flow, genetic drift, adaptive radiation
Mutation
- Errors in the replication of DNA, the ultimate source of variation within populations
- Can occur simply as copying errors or from exposure to radiation, chemicals and viruses
- The reason why bipedalism and larger brains emerged in humans
Sexual selection
Personal mate selection (choosing a mate based on physical features or cultural factors)
Gene flow
When genes move between populations that are members of the same species but who do not normally mate together
Genetic Drift
A random factor in evolution,
When changes in allele frequency occur by chance (ex- when a small group leaves its parent population and begins a new population elsewhere)
Adaptive radiation
Occurs when a species rapidly adapts to an ecological niche, often expanding its population quickly and diversifying into multiple species
What 2 models pertain to the speed at which evolution occurs
Gradualism & Punctuated equilibrium
Gradualism
suggests a slow steady change with a new species eventually emerging
Punctuated Equilibrium
suggests a slow steady change occasionally interrupted by short periods of significant change
explains the lack of transitional forms in the fossil record
Species
a population of individuals that can mate and produce fertile offspring in the wild
Speciation
the process by which new species emerge, can happen in numerous ways such as geographic isolation or a single population of species that evolves into another species
Genetics
the study of individual genes and their role in inheritance
Genome
the entire genetic makeup of an individual or species
Genomics
the study of genomes
Epigenetics
refers to the study of how factors other than DNA or genes may influence the occurrence of specific traits, can change a phenotype without a corresponding change in the genotype
Mosaic evolution
a phenotypic pattern that shows how different traits of an organism, respond to different selection pressures may evolve at different rates
Homo naledi
recent discovery of homo that showed possible evidence for burial practices
Australopithecines
possibly emerged from Ardipithecus
adapted to bushlands, open savannah, and aquatic fringes
entomophagy
eating insects
Linnaeus
devised the naming system we still use for living organisms which was called Linnaean taxonomy
Lamarck
proposed that organisms responded to their environments by changing and those changes would be passed on to subsequent generations (transformism)
Cuvier
by studying the fossil record he came to believe that some species had been abruptly wiped out and replaced by a new species (catastrophism)
Lyell
believed that the world was a product of gradual changes throughout time, these changes ongoing and that we can see them in geology (uniformitarianism)
“the present is the key to the past”
Great chain of being
hierarchical structure of life thought by medieval Christianity to have been decreed by God
Charles Darwin
2 key elements: common origin and natural selection
Common origin
studied by looking at phenotypes and later on genotypes as well and comparing the traits by relatedness
Natural selection
there are differences between individuals that make them more or less likely to survive
Darwins theory of evolution (Variational evolution) (4)
- there is variation in a population
- only part of a population reproduces
- traits are heritable
- advantageous traits eventually become more frequent in a population
Gregor Mendels discoveries (4)
- traits are determined by specific units or factors (genes) in individuals which are passed onto offspring
- An individual inherits one unit from each parent (alleles)
- Even though an individual has a specific trait, it may not be observable but can still be passed on
- He is responsible for figuring out dominant & recessive alleles, and the differences between genotype & phenotype
Microevolution
small evolutionary changes that occur within a single species over relatively few generations, involves ecological time, leads to alterations in the gene pool, ex- new strains of viruses
Macroevolution
changes that lead to new species and their diversification across space and over millions of years, measured in geological time, leads to speciation, ex- development of bonobos and chimps from a common ancestor