Unit B: Evolution in Action Flashcards
Topic 2
Hox genes:
master regulator genes that direct the development of body segments.
- the idea that embryos have special coding that indicate where each body part will grow and its relation to this region.
- Scientists have experimented by changing the hox genes around and seeing legs grow out of the antena of fruit flies.
Gondwana:
a hypothetical landmass in the Southern Hemisphere that separated toward the end of the Paleozoic Era to form the different continents today.
Tectonic plates:
large sections of the Earth’s crust that move independently. The theory of plate tectonics explains that the Earth’s crust, or lithosphere, is divided into sections called plates. These tectonic plates are solid and drift on currents of the underlying mantle.
Transitional fossil:
fossils that show intermediary links between groups of organisms (link past with the present and have similar traits with the descendant group)
Help scientists to look at the evolutionary past of animals and how they evolved/how traits were passed down
Geological Uplifting:
the movement of fossils up to the top of the mountain over a long period of time that were previously buried by sediments.
Radiometric dating:
strong evidence for evolution → a method used to establish how old an object is by measuring the amount of radioisotope the object contains against the decay product it contains.
Biochemical Evidence:
the use of molecular biology techniques to study the chemical processes and substances that occur within living organisms, providing crucial insights into evolutionary relationships.
Geologic time:
the billions of years since the planet Earth began developing.
Fossil record:
in sedimentary rock that shows the history of life and species that were alive in the past.
Artificial selection:
traits must be heritable, it isn’t instant and can take hundreds of generations to select for particular traits depending on the organism and the trait, they are not always beneficial to the organisms (dogs and the medical problems that arise)
Variation:
a visible or invisible difference that helps and individual in a population survive is likely to be passed on from survivor to survivor → variations become more common over time, changing to be a characteristic or trait of that population.
Adaptation:
variations that give an individual a better chance of survival to reproduce will be passed onto offspring (becomes more common in certain populations throughout many generations)
Advantage is passed on to help survive in specific environment
The environment has an influence on structure and function)
Increased fitness and changes to help organisms survive
Mutations:
changes in the genetic material of an organism. → happen continuously in the DNA of any living organism.
Change in DNA (genetic code)
Cause of variation and DNA replication which divides and replicates the cell
Interspecific: between species, physical differences
Example: fish and humans (gills vs legs and other organs)
Intraspecific:
variation within each species
Example: different breeds of dogs (frenchie v labrador)
Speciation:
changing enough over time to become 2 different species (gradual) because of the environment and natural selection. From a singular population, genetic variation happens before the change to increase the chances of survival *the species is so different that they can no longer interbreed (DNA changes)
Natural selection:
a process that results when the characteristics of a population of organisms change because individuals with certain inherited traits survive specific local environmental conditions and, through reproduction, pass on their traits to their offspring. For natural selection to occur, there must be variety or diversity within a species.
Evolution:
the change in the characteristics of a species over several generations and relies on the process of natural selection. The theory of evolution is based on the idea that all species are related and gradually change over time.
GMO
animal or microbe in which one or more changes have been made to the genome, typically using high-tech genetic engineering, in an attempt to alter the characteristics of an organism.
Monoculture
(tomato example). From this, there is a decrease in the natural diversity leading to the wipe out of whole varieties of organisms before they can adapt
Selective breeding:
in the world of agriculture, choosing individuals with mutations that favour certain traits and breeding them with similar individuals allows for an increased likelihood of those traits showing up in offspring
Selecting for large, fast-growing individuals has resulted in the broiler chicken (fatter with more muscle and much heavier)
Inbreeding:
aggressively selecting certain traits, humans reduce genetic variation in a species by breeding individuals with similar genetic traits → decrease in variation
Lamarck:
he looked at the changes in species over time → comparing current species with fossils of ancestor mammals
Came up with the idea of inheritance of acquired characteristics: thought that characteristics like muscles acquired during an organism’s lifetime could be passed onto their offspring.
As biologists learned more about cells, genes and heredity in the late 1800s, his theory was rejected.
Darwin:
1831, had an expedition with the purpose of of mapping the coast of south america.–> provided the opportunity to explore the history of various countries and locations.
by starvation or disease. According to Darwin and Wallace,individuals with physical, behavioural, or other traits that helped them survive in their local environments were more likely to survive to pass on these traits to offspring. Darwin and Wallace reasoned that competition for limited resources among individuals of the same species would select for individuals with favourable traits—traits that increased their chances of surviving to reproduce.
Gradualism:
gradual changes occur steadily in a linear matter of time
- evolution occurs through the gradual accumulation of small changes. The intermediate stages of evolution not represented by fossils merely testify to the incompleteness of the fossil record.
