Evolution lab practical 1 Flashcards
Evolution
Descent with modification. Involves changes in allele frequencies over time
Natural selection
the selection for those phenotypes that are better adapted with the result that such phenotypes contribute more surviving offspring to the population than other phenotypes
When does evolution occur (5 factors)
- Mutation: produce variation in the gene pool
- Gene flow: frequency of genes in the gene pool may change due to immigration or emigration
- Natural selection: impact of the environment on the frequency of alleles
- Genetic drift: frequency of alleles in the gene pool may change by pure chance
- Nonrandom mating: if there is a mating preference in the population, the frequency of alleles in that population will change
Dichotomous key
A tool that allows the user to determine the identity of items in the natural world. They consist of a series of choices that lead to the correct name of the given item
Cladogram
A branching diagram showing relationship between a number of species. They focus on identifying common ancestry of related groups
Name the six kingdoms and give an example of each
Plants (trees), animals (human), protists (protozoa, algae), fungi (yeast), archeabacteria (crenarchaeota), eubacteria (e. coli)
How are scientific names derived
The first word is the genus the species belongs to. The second word is specific to the organism and is called the species epithet. The words are greek or latin
Castle-Hardy-Weinberg law
simple mathematical expression that establishes a point of reference in evaluating genetic changes in a population
Castle-Hardy-Weinberg formulas
p+q=1
p^2+2pq+q^2=1
Castle-Hardy-Weinberg conditions
- Mutations do not occur
- The population size is large
- The population is isolated from other populations of the same species (no immigration or emigration occurs)
- No selection takes place (the genotypes are equally viable and fertile)
- Mating is random
Taxonomy
The study of the principles, procedures, and rules of scientific classification and the naming of organisms
(Science of classifying organisms)
Phylogenetics
What cladistics is sometimes referred to because cladograms are generated from similarities in the molecular structure of organisms
Theory of evolution
postulates that the modern species of organisms are descendants of a common ancestor and that their present characteristics have come from genetic variation and natural selection
Species
Members of a species share common genes and can breed to produce fertile offspring
Fossil
A preserved remnant or impression of an organism
Fossil record
the sequence of fossils from the oldest to the most recent
Homologous structures
Structures who’s similarity is due to descent from a common ancestor
Divergent evolution
What homologous structures result from as related organisms expand into new environments
Analogous structures
Have similar functions in unrelated organisms (ex: butterfly and bat wings)
Convergent evolution
What analogous structures result from when unrelated organisms are objected to similar environmental pressures
Timeline of human evolution in order
- Ardipithecus ramidus
- Australopithecus afarensis
- A. africanus
- A. boisei
- A. robustus
- A. habilis
- Homo erectus
- Homo neanderthalensis
- Homo sapien
When were Hominids around in Africa
8 to 5 mya
When did the earliest hominid (a. ramidus) live
4.4 mya
When did the oldest austra…. live (a. anamensis)
4 mya
What was pangea
Pangea was the super continent during the Permian period
How does pangea relate to the fossil record
Fossils of the same organisms were found on two separate continents, suggesting that they were connected when those organisms roamed the earth. When the continents separated, organisms evolved to their environments. Today, organisms on separate continents have features that show they share a common ancestor
Unity in evolution
We are united through common ancestry
Diversity in evolution
We are diverse because of our physiology, morphology, etc. due to evolution over time
Evidence of common ancestor in embryos
Early embryos of different organisms look nearly identical. All possess pharyngeal pouches, aortic arches and post anal tail
Evolution postulates
- Modern species of organisms are descendants of a common ancestor
- Their present characteristics have come from genetic variation and natural selection
Antibodies
proteins that protect against forgein proteins that enter the body
Antigens
foreign proteins that enter the body
Out-of-africa hypothesis
proposes that early H. sapiens evolved from H. erectus in Africa about 150,000 years ago and migrated to other parts of the world
Multiregional hypothesis
Holds that localized populations of early H. sapiens evolved independently from H. erectus in several regions of the world
What general trend is evident in organismic diversity
As time went on, diversity increased. This is because many new species evolved from the original ancestors
What general trend is evident in organismic complexity
As time went on, complexity increased. This is because over time, organisms developed adaptations to better survive in their environments
Are there exceptions to the trend of diversity and complexity increasing as time goes on
Yes. Today there are still simple organisms that lived in earth’s early years that survived mass extinctions
How did cyanobacteria prepare the way for the origin of aerobic respiration
They undergo photosynthesis and release oxygen into the atmosphere
Considering the drifting of continents, how do you explain the presence of fossils or tropical organisms in Canada
Canada was once in the tropics so tropical organisms once flourished there
Considering the drifting of the continents, how do you explain the absence of marsupials and the presence of native placental mammals in Australia
Australia was probably one of the first continents to break off of Pangea
For a group of organisms to radiate, there must be niches (ways of making a living) available for the taking. What made niches available for the radiation of:
1) mammals:
2) amphibians:
1) Mammals: the extinction of dinosaurs (loss of competitiors)
2) Amphibians: they didnt have much competition and the closeness of the continents to eachother allowed them to spread out
Extinction is a common occurrance in the fossil record. Why do you think species become extinct
They become extinct because they are unable to adapt
All organisms possess ATP, RNA, and DNA. What can you infer from this
There is a common ancestor
Would you expect plasma proteins of closely related species or distantly related species to have the greater similarity?
The more closely related they are, the more similar the protein structure
If you want to identify the various species of birds in you backyard, what sources could you use to fins their names
A dichotomous key could be used. By observing the characteristics of each species, you could use the dichotomous key to narrow down the possibilities
How does the cladistics system of taxonomy differ from the hierarchial system of classification
Cladograms show relationships between organisms by trying to identify a common ancestor. A heirarchial system of classification begins broad and organisms become more similar with each level. Sometimes, cladograms do not align with the actual evolutionary past. They are only hypothesis until the genetic data becomes available.
Evidence of evolution from embryos
They all posess pharyngeal pouches, aortic arches, post anal tail . All veterbrates have similar genes directing early embryonic development (common ancestor)
Evidence of evolution from vertabrate anatomy
Forelimbs in each organism exhibit similar basic body plan (common ancestor). Bones specialized for particular functions in each organism
Does evolution of a body part produce the single best structural design or a functional modification of the basic structure available?
No. Depending on the environmental situation, it will evolve differently.
