Mini Exam 1 Flashcards
When did life on Earth begin?
Life on Earth began approximately 3.5-4 billion years ago with simple single-celled organisms
When was the Great Oxidation Event?
The Great Oxidation Event (~2.4 billion years ago) was when photosynthesizing cyanobacteria started producing oxygen, transforming Earth’s atmosphere and enabling aerobic life.
When was the Cambrain Explosion?
The Cambrain Explosion (~540 million years ago) was a period of rapid diversification where many of the major animal phyla first appeared.
What major event allowed organisms to colonize land?
Around 450 million years ago, plants, arthropods, and vertebrates moved onto land drastically changing ecosystems.
What are mass extinction events, and name two major examples.
Mass extinction events wipe out large percentages of species. Two examples are the Permian-Triassic extinction (~252 million years ago) and the Cretaceous-Paleogene extinction (~66 million years ago)
How does natural selection drive evolution?
Natural selection drives evolution by allowing organisms with beneficial genetic mutations to survive and reproduce, leading to adaptation and speciation.
What has varied over time in Earth’s history?
Biodiversity, atmospheroc compostition, climate, geography, and ecosysyem dynamics have all varied throughout Earth’s history.
How was the atmospheric composition changed during Earth’s history?
The atmosphere has evolved, notably with the increase of oxygen during the Great Oxidatijon Event and the more recent rise in CO2 due to human activity.
What are the main drivers of change in the history of life?
Geological and climate factors, biological innovations, mass extinctions, and co-evolutionary relationships are the main drivers of change.
How has plate tectonics influenced life on Earth?
Plate tectonics caused continental drift, altering habitats, species distributions, and the evolution of life.
How has climate change influenced life on Earth?
Climate change, such as ice ages and warm periods, has led to significant shifts in ecosystems, species extinction, and the rise of new species.
What role did evolution of photosynthesis play in the history of life?
Photosynthesis, especially oxygen-producing photosynthesis, was key in transforming Earth’s atmosphere and allowing aerobic organisms to evolve.
What is adaptive radiation, and when does it usually occur?
Adaptive radiation is the rapid diversification of species to fill ecological niches, often occuring after mass extinction events.
What is the Anthropocene?
The Anthropocene is the current geological epoch where human activity is the dominant influence on the Earth’s climate and ecosystems.
What are some characteristics of the Anthropocene?
The Anthropocene is characterized by climate change, mass extinctions, land use changes, and widespread pollution driven by human activities.
How is human activity contributing to a sixth mass extinction?
Human activities, such as habitat destruction, pollution, and overexploitation, are causing species to disappear at rates much higher than the natural background rate.
How has land use changed in the Anthropocene?
Agriculture, urbanization, deforestation, and habitat fragmentation have drastically altered ecosystem, reducing biodiversity.
What are the implication of the Anthropocene?
The Anthropocene raises concerns about sustainability, biodiversity loss, and long-term ecological impacts, emphasizing the need to address human-induced changes.
What is evolution?
change in genetic composition of a population over time
POPULATIONS EVOLVE, INDIVIDUALS DO NOT
What is natural selection?
Natural selection is the process where organisms with favorable traits are more likely to survive and reproduce, passing those traits to future generations
What is genetic drift?
Involves random changes in allele frequencies in a population, often having a more significant effect in small populations
What is gene flow?
Gene flow is the transfer of genetic material (alleles) between populations, which can introduce new genetic variations to a population
What is a mutation?
Change in the DNA sequence that can introduce new genetic variation (alleles) into a population
What are alleles?
Alleles are different versions of a gene that can result in different traits
What is speciation?
Speciation is the evolutionary process by which populations evolve to become distinct species
What is an adaptation?
An adaptation is a heritable trait that increases an organism’s fitness, or ability to survive and reproduce in a specific environment
What are the sources of genetic variation?
Mutations, gene flow, and sexual reproduction (which reshuffles alleles during Meiosis)
How do mutations contribute to evolution?
Mutations introduce new alleles into a population, providing the raw material for evolution
What is sexual reproduction’s role in genetic variation?
Sexual reproduction increase variation through the recombination of alleles during meiosis and fertilization
What is non-random mating?
Occurs when individual preferentially choose mates based on certain traits, potentially leading to changes in allele frequencies
What is the bottleneck effect?
Type of genetic drift where a population’s size is drastically reduced, leading to a loss of genetic diversity
(Natural disasters, disease outbreaks, or human activites like hunting)
What is stabilizing selection?
Type of selection that favors the average individual in a population and reduces variation
What is directional selection?
Occurs when one extreme phenotype is favored over others
What is disruptive selection?
Type of selection that favors individuals at both extremes of a trait and selects against those with intermediate traits
What is sexual selection?
Selection based on traits that improve an individuals chances of mating and reproducing.
What is the founder effect?
Type of genetic drift that occurs when a small group of individuals establishes a new population, leading to reduced genetic variation compared to the original population.
How does natural selection lead to adaptation?
Natural selection favors individuals with traits that increase their survival and reproduce success in a given environment, leading to the prevelence of those traits over generations
What is an example of natural selection in action?
The peppered moth: during the Industrial Revolution, moths with darker colorization were better camouflaged in polluted areas and became more common
What is an example of gene flow?
Gene flow occurs when individuals from one population of bird migrate and breed with another population, introducing new alleles into the second population
What is an example of genetic drift?
The cheetah population experienced a bottleneck, resulting in reduced genetic diversity and making them more vulnerable to environmental changes
How can artifical selection serve as an example of evolution?
In artificial selection, human breed plants and animals for specific traits, such as larger fruits in agriculture or faster horses in racing, showcasing how selective pressures can shape species
What is convergent evolution?
When different species evolve similar traits independently, often due to similar environmental pressures (wings in bats and birds)
What is an example of speciation?
Darwin’s finches on the Galapagos Island are an example of speciation, where different populations evolved break shapes based on food availability on different islands
How does evolution affect human health (application example)?
Evolution of antibiotic resistance in bacteria occurs due to the selective pressure exerted by antibiotics, leading to the rise of resistant strains
What is ecology?
Ecology is the study of how organisms interact with each other and their environment
What is a population?
A population is a group of individuals of the same species living in a specific area at the same time
What is a community?
A community is all the populations of different species living and interacting in a particular area
What is an ecosystem?
An ecosystem includes all living organisms (biotic factors) in a particular area, along with nonliving (abiotic) factors with which they interact
What is biodiversity?
Biodiversity refers to the variety of life in an area, including species diversity, genetic diversity, and ecosystem diversity
What is carrying capacity (K)?
Carrying capacity is the maximum population size that an environment can support indefinitely withing degrading the habitat
What is exponential growth?
Exponential growth occurs when a population increases by a constant proportion over time, often represented by a J-shaped curve
What is logistic growth?
Logistic growth occurs when population growth slows as it approaches carrying capacity, forming an S-shaped curve
What is the intrinsic rate of increase (r)?
The intrinsic rate of increase is the maximun potential growth rate of a population under ideal conditions.
What are density-dependent factors?
Density-dependent factors are biotic factors, like competition, predation, and disease, that limit population growth based on population size
What are density-independent factors?
Density-independent factors are abiotic factors, like weather or natural disasters, that affect population size regardless of density
What is a keystone species?
A keystone species is one that has a disproportionately large impact on it ecosystem relative to its abundance
What is ecological succession?
Ecological succession is the gradual process of change in species composition of a community over time, following a disturbance.
What is primary succession?
Primary succession occurs in lifeless areas where soil has yet to form, such as after a volcanic eruption
What is secondary succession?
Secondary succession occurs in areas where a disturbance has destroyed a community but left the soil intact, such as after a forest fire
What is a food chain?
A food chain is a linear sequence of organisms where each is eaten by the next, starting with a primary producer and ending with top predators
What is a food web?
A food web is a complex network of interconnected food chains in an ecosystem showing how different species are connected through feeding relationships
What is a trophic level?
A trophic level refers to a position in a food chain or web, such as primary producers, herbivores, or carnivores
What is species evenness?
Species evenness measures how equal the populations of different species are in a community contributing to biodiversity
