Biology Test Three Flashcards
Population
Group of organisms of the same species living together in the same geographic area.
Formed by a new allele making genetic changes in a species, thus making or changing a species to have an advantage.
Natural selection/ Adaptive evolution
Darwin
Environment selects favorable traits to have species be more adaptive and have higher reproduction rate.
Differential survival and reproduction of individuals in response to environmental pressure that leads to change in allele frequencies In a population over time.
Leads to adaptation
Acts on the phenotypes of organisms
Descent of modification
Darwin’s idea of natural selection was original contribution to this theory.
Combines the ideas that all living things are related sharing common ancestors in distant past and that organisms have changed over time.
Evolution
Change in allele frequencies in a population over time.
It’s the gradual change of species over time.
Nonadaptive evolution
Any change in allele frequency that does not by itself lead a population to become more adaptive to its environment
Caused by mutations.
Caused by genetic drift
Caused by gene flow
Mutations
Cause of Nonadaptive evolution
Introduces new alleles into a population.
Change in a gene frequency
Results in evolution.
Genetic drift
Cause of Nonadaptive evolution
Change in allele frequencies between generations that occurs purely by chance.
Completely random
Decreases the genetic diversity of a population
Two types: founder effect, bottleneck effect
Founder effect
Type of genetic drift
Small number of individuals or founders leave one population and establish a new population .
May have lower genetic diversity than original population.
Bottle neck effect
Type of genetic drift
Occurs when a population is suddenly reduced to a small number of individuals and alleles are lost from the population As a result
Less genetic diversity or extremely poor gene pool.
Can occur from natural causes
Gene flow
Cause of Nonadaptive evolution
Movement of alleles from one population to another
May increase genetic diversity of a population
Aka migration
Ex. Pollen being blown to a new destination.
Fit
Organisms fitness
Fitness
Relative ability of an organism to survive and reproduce in a particular environment.
Gene pool
Each population of any organism has its own particular collection of alleles.
Total collection of allele in a population.
Allele frequency
Within the gene pool
Relative proportion of an allele in a population.
Genetic diversity importance
Diverse gene pool gives a pop. More flexibility to survive in a changing environment
Improve evolutionary success.
Tiktaalik roseae
Between 4-9 ft long
Had fins, scales, a mobile neck, jointed wrist, finger like bones, flat skull, flexible neck, long sturdy ribs.
It was a predatory fish with sharp teeth.
Intermediate or transitional fossil between figs and tretrapods
Fossils
Preserved remains or impressions of a once living organism that provides a record of past life on earth.
Direct evidence of evolution.
Ways fossils are formed
Frozen, trapped, buried, leave imprint
Two kinds of fossil dating
Relative-determine age of fossil from its position relative to layer of rock or fossils of known age.
Deeper down they are buried, the older they are.
Radiometric- the rock layers formed from volcanic eruptions. Can be directly dated using Radiometric dating.
Used as a geological clock.
Ratio of radioactive elements of uranium and lead in the rock determine the age.
Fossil record
Group of fossils arranged in order of age providing evidence of changes in species over time.
Homology
And the three forms
Anatomical genetic DNA,or developmental similarity among organisms due to common ancestry.
3 forms:
Anatomical- number, order, and structure of the forelimb bones.
Embryological- similar e structures in vertebrates are evidence that all vertebrates share common ancestor.
DNA- closely related species have similar DNA inherited from ancestors.
Biological species concept
Defines a species as a population whose members can interbreed and produce fertile offspring.
Taxonomy
The process by which scientists systematically identify the name and classify organisms on the basis of a shared trait.
Taxonomists
Scientists who identify, name, and classify organisms.
Scientific name
Written in italics
Genus is first and uppercase
Species is second and lower case
Classification of species
Domain Kingdom Phylum Class Order Family Genus Species
Modern system of classification
Bacteria
Archaea
Eukarya- encompasses multicellular and unicellular organisms that are grouped together by their similar DNA sequences
Kingdom- Plants, animals, fungi, Protists within eukarya domain.
Reproductively isolated species
Members of different species cannot breed with each other
Occurs as a result of mechanisms that prevent mating including the gene flow between members of different species.
Factors that cause isolated species
Ecological- two species live in dif environments become isolated and never encounter one another
Temporal- mating fertility or behavior at dif times
Mechanical- mating organs are incompatible
Gametic-gametes of two species cannot unite.
Speciation
Genetic divergence of population of the same species when a barrier prevents gene flow between them, leading over time to reproductive isolation and the formation of new species.
Barrier can be river, mountain, hill, ocean.
Extinction
Elimination of all individuals in a species
May occur over time or a sudden mass die off
Two massive extinctions
Permian- occurred 290mil years ago. 95% of species died off.
Cretaceous- occurred 65mil years ago. 60% of other species and dinosaurs died off.
Three domains of life
Bacteria, archaea, and eukarya.
Three fundamental branch points in the trunk of the evolutionary tree.
Prokaryotes
Unicellular organisms that lack internal membrane bound organelles.
No nucleus
Single circular DNA molecule floats freely in cytoplasm.
Bacteria and archaea
Bacteria
Domain of prokaryotes
Some are
autotrophs- self feeders and harmless and beneficial. Ex. Cyanobacteria.
Heterotrophic- obtain food by consuming materials. Important de composers.
Disease causing pathogens by producing toxins. Staff bacteria is bad.
Domains of archaea
Domain of prokaryotic life.
Known as extremophiles since they live in harsh environments.
Many are anaerobic- no oxygen and rely on sulfur in their metabolism. Ex. Methanogens.
Eukaryotes
In the eukarya domain.
Have membrane enclosed nucleus and organelles.
Contains plants, fungi, animal, and Protists
Plant diversity
Multicellular eukaryotes that carry out photosynthesis. Has cell wall and is adapted to living on land.
Land plants evolved first from water dwelling algae.
Vascular plant- plant with tissue that transports water and nutrients thorough plant body.
Evolution:
bryophytes-made transition from water to land. Non vascular and don’t produce seeds. Moss
Fern-first true vascular plant. No seeds. Can stand upright reproduces by spores.
Gymnosperm-vascular. Cell walls provide support. Grows tall. Naked seeds. Pine
Angiosperm- flowering plants. Vascular. Have seeds contained in fruit. Rose, Lilly, maple
Animal diversity
Multicellular eukaryotic organism. Heterotrophs. Body is symmetrical.
Vertebrae: bony backbone CHORDATES.
Invertebrate: animal lacking backbone.
Insects and Arthropods.
Fungi
Unicellular or multicellular eukaryotic organism.
Obtains nutrients by secreting digestive enzymes onto organic matter or dead organisms and absorbing digested product.
Decomposers- digest and use organic molecules in dead organisms as fuel.
Protist
Eukaryotes. Cannot be classified as plant, animal, or fungus.
Usually unicellular.
Include photosynthetic plantlike algae and animal like protozoans.
Lack adaptations to live on land such as roots stems and leaves.
Mitochondrial DNA
DNA in the mitochondria. Solely inherited from mothers.
Located in the mitochondria of our cells.
Powerful tool by which to track human ancestry back hundreds of Generations.
Used to construct an evolutionary tree of humanity.
There is a mitochondrial eve that we all can trace back to.
