Intro to Evolution Flashcards
paleontology definition
the study of fossils, largely developed by Georges Cuveir
Catastrophsim definition
speculating that each boundary between strata represents a catastrophe
Uniformitarianism definition
states that the mechanisms for change are constant over time
What did James Hutton and Charles Lyell perceive?
They perceived that changes in Earth’s surface can result from slow continuous actions still operating today
Lamarack’s Hypothesis of Evolution?
He hypothesized that species evolve through use and disuse of body parts and inehritance of acquired cahracteristics
Was Lamarack’s Hypothesis of Evolution correct or incorrect?
INCORRECT
What were the two main ideas Darwin developed?
Descent with modification and Natural Selection
What is descent with modification?
with modification, summarized Darwin’s view of the unity of life, referring to the view that all organisms are related through descent from an ancestor that lived in the remote past
What is Artificial selection?
When a species evolves in a controlled manner - humans modify other species by selecting and breeding individuals with desired traits
How many observations did Darwin make and how many inferences?
4 Observations and 2 Inferences
What was the first observation that Darwin made?
Members of a population often vary greatly in their traits
What was the second observation that Darwin made?
Traits are inherited from parents to offspring
What was the third observation that Darwin made?
All species are capable of producing more offspring than the environment can support
What was the fourth observation that Darwin made?
Many of these offspring to not survive by lack of food or other resources
What was Darwin’s first inference?
Individuals whose inherited traits give them a probability of surviving and reproducing in a given environment tend to leave more offspring than other individuals
What was Darwin’s second inference?
The unequal ability of individuals to survive and reproduce will lead to the accumulation of favourable traits in the population over generations
where are most fossils found?
sedimentary rock
What are the four types of fossils?
- whole animal/plant
- petrifaction
- imprints
- mould/casts
what is a whole animal/plant fossil + examples?
- preservation of soft and hard body parts very rare
- insects entombed in amber (preserved so well, to be studied as though they had just died-intact DNA)
- frozen Mammoth carcass and human remains (even after 40 000 years)
what is a petrifaction fossil + examples?
- remains of the organism are turned to stone
- organic substances (soft parts) decay, but water containing minerals soak into the cavities and pores of hard structures (bones, shells, eggs, etc.)
- water slowly dissolves original hard parts and replaces them with minerals (turns to rock)
what is an imprint fossil + examples?
- outlines of feaves, feathers, footprints
- significance of footprints :depth, size and distance between
- provide information about weight, length and bone structure
What is a mould/cast fossil?
- living organism is buried in mud/clay which eventually hardens (eventually to rock)
- body dissolves away, leaving a cavity within the hard material
- cavity is filled with stone in the shape of the original creature
What can fossils can tell?
- Body size
- weight
- age
- location
- migration
- cause of extinction
- diet
- common origins (missing links)
How can age be determined?
- can be determined by the location of the fossil deposits
- assuming chronology for strata and sequence of location of fossils in the layers
- absolute age can be found by radioactive dating
What is biogeography?
species tend to be more closely related to other species from the same area than to other species with the same way of life but living in different areas
What are analogous structures?
body parts that have the same function but different structures
What are vestigial structures?
strucutres present in a species that is of either marginal or no apprent use to the organisms of that species
What are the three major domains?
Archaea, Bacteria, and Eukaryota
Clade definition
A groupd of organism s that includes a common acestor and all the descendants - both living and extinct.
What is comparative embryology?
Comparing embryo formation
What is modern Synthesis?
Consensus of the following two theories:
- Gradual evolution results from small genetic cahnges that are acted upon by natural selection.
- The origin of species and higher taxa, or macroevolution, can be explained in terms of natural selection acting on inidivudals or microevolution
What are the 5 evidences for evolution?
- Fossils
- Biogeography
- Comparative embryology
- Evolutionary Change as Observed Through Artificial selection
- Molecular Biology as Evidence of Evolutionary Relationships
What is relative dating?
a technique used to determine which of two fossils is older. Uses the age of sedimentary layers to determine relative age.
What is an uncomformity?
a gap in the rock sequence
Why do uncomformities occur?
- agents of erosion (water, wind, glaviers) more layers or parts of layers away
- no deposition occurs in that area
- Earthquakes movement has caused ground to be uplifted
what is the parent atom?
the original atom?
What is the daughter atom?
The new form of the atom
What are the 4 mechanisms of change?
- mutation,
- migration
- genetic Drift
- Natural Selection
What is mutation?
the genetic makeup of organisms change from one to the next
What is migration?
some individuals from one population move a reproduce with species from another population
What is genetic drift?
not actually evolution, some things happen randomly
Where do mutations need to occur to be passed onto the next generation?
In reproductive cells (sperm and egg) NOT SOMATIC
gene flow definition
any movement of genes from one population to another and is an important source of genetic variation
What are the three modes of selection?
- directional selection
- disruptive selection
- stabilizing selection
What is directional selection?
Favors individuals at one end of the phenotypic range
What is disruptive selection?
favors indivuduals at both extremes of the phenotypic range
What is stabilizing selection?
favors intermediate variants and acts against extreme phenotypes
What is adaptive Radiation?
A single species rapidly adapts to fill available niches in an environement
What is microevolution?
consists of adaptations that evolve within a population confined to one gene pool
What is macroevolution?
It refers to evolutionary change above the species level
What is the biological Species concept?
The biological species concept states that a species is a group of populations whose members have the potential to interbreed in nature and produce viable, fertile offspring; they do not breed successfully with other populations.
What is reproductive isolation?
the existence of biological factors (barriers) that stop two species from producing viable, fertile offspring
What are hybrids?
offspring of crosses between different species
What are prezygotic barriers?
Barriers that prevent a zygote from being formed
What are 3 examples of prezygotic barriers?
- stopping different species from attempting to mate
- prevent the successful completing of mating
- hinder fertilization if mating is successful
What is habitat isolation?
Two species live in different habitats so they encounter each other rarely or not al all.
What is temporal isolation
When species breed at different times of the day/season/years/ so their gametes cannot mix
What is behavioural isolation?
When coutrship rituals and othe behaviours are unique to species such that they are an effective barrier
What is mechanical isolation?
Morphological differences that prevent mating
What is gametic isolation?
when the sperm can’t fertilize the egg
What is a postzygotic barrier?
something that prevents the hybrid zygote from developing into a viable fertile adult
What is reduced hybrid viability?
genes of the different parent species may interact and impair the hybrid’s development
What is hybrid fertility?
even if hybrids are healthy, they may be sterile
What is hybrid breakdown?
some first-generation hybrids are fertile, but when they mate with another species or with either parent, offspring of the next generation are feeble or sterile
What can the biological species concept NOT be applied to?
It cannot be applied to fossils or asexual organisms (all prokaryotes)
What are the two ways speciation can occur?
Allopatric speciation and sympatric speciation
What is allopatric speciation (“other country”)?
Gene fow is interrupted or reduced when a population is divided into geographically isolated subpopulations. Seperate populations may evolve independently through mutation, natural selection and genetic drift
What is evidence for allopatric speciation?
regions with many geographic barriers typically have more species than rgions with fewer barriers
What is sympatric speciation (“same country”)?
speciation takes place in geogrpahically overlapping populations.
population definition
a loxalized group of individuals capable of interbreeding and producing fertile offspring
gene pool definition
consists of all the alleles for all loci in a population
What is a fixed locus?
when all individuals in a population are homozygous for the same allele
What is the Hardy-Weinberg principle?
it describes a population that is not evolving - it states that frequencies of alleles and genotypes in a population remain constant from generation to generation
What is Hardy-Weinberg equilibrium?
It describes the constant requency of alleles in such a gene pool
What are the 5 conditions for non-evolving populations?
- no mutations
- random mating
- no natural selection
- extremely large population size
- no gene flow
