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Biological evolution
Change in a population's gene pool over time, leads to changes in frequency of appearance/behavior from generation to generation.
Gene pool
All of the genes present in a population.
Genes
Control pattern and color (of eg. fish scales).
Mutation
Changes in DNA that give rise to genetic variation, such as a mutation in sperm/egg cell that may be passed to the next generation.
Migration
Population change due to immigration or emigration that causes a change in the proportion of traits in the gene pool.
Genetic drift
An unusual event (natural disaster or fishing net) that kills/separates all but a few individuals, resulting in a different gene pool for the next generation.
Natural selection
The process where certain traits become more or less common in a population due to the survival and reproduction of individuals with those traits.
Conditions of natural selection
Factors that explain patterns seen in nature, including the relationship between organisms and their environment.
Condition 1 of natural selection
Organisms produce more offspring than can survive, leading to a struggle for existence due to limiting factors.
Condition 2 of natural selection
Individuals of a species vary in their characteristics, with variations being heritable if passed from parent to offspring.
Condition 3 of natural selection
Individuals vary in fitness, where variations can be harmful or helpful, affecting survival and reproduction.
Survival of the fittest
High fitness individuals produce more offspring and pass genes more frequently than low fitness individuals.
Fitness
Defined in context of environment, can change based on conditions, and traits that are adaptive may vary by location or season.
Artificial selection
Results of natural selection visible in adaptations, where humans breed organisms for desirable traits.
Artificial selection with dogs
Diverse dog breeds are variations on a single species, with any two dogs able to interbreed and produce offspring.
Artificial selection with agriculture
Most crop plants for food are based on artificial selection, resulting in diversified single plant species into many different crops.
Example of biological evolution
40% brown mice and 60% tan mice → 28% brown mice and 72% tan mice.
FOUR PRIMARY MECHANISMS/PROCESSES
Mutation, migration, genetic drift, natural selection.
Darwin's publication
In 1859, Charles Darwin published 'On the Origin of Species', providing decades of scientific evidence for natural selection.
Limiting factors
Restrictions that prevent all individuals in a population from reproducing to their full biotic potential.
Heritable variations
Variations among organisms that are due to differences in genes/environments and can be passed from parent to offspring.
High fitness individual
An individual that produces more offspring and passes genes more frequently than low fitness individuals.
Adaptive traits
Traits that maximize success in a given environment, which may change based on location and conditions.
Selective breeding
The process where humans choose and breed animals or plants with desirable traits.
Broccoli, cabbage, brussel sprouts, cauliflower
From Brassica oleracea
SPECIATION/EXTINCTION
Reason why Earth has many species, estimated all species today are a tiny fraction of those that have ever lived
SPECIATION
Occurs in many ways, speciation caused by geographic separation of populations = most important (allopatric speciation)
Allopatric speciation
Speciation caused by geographic separation of populations
Genetic divergence
Occurs when mutations in DNA of an organism in one isolated population cannot spread to other populations
Long-term geographic isolation
Can lead to allopatric speciation and can happen in many ways (e.g., glacial ice sheets moving across continents, rivers changing, dry climate partially evaporating lakes)
Isolation process
Must be long (generally thousands of generations) for speciation to happen
Speciation process
One species is separated into groups and those mutations in each individual group cannot mix with the others
EXTINCTION
About 99% of all species that ever lived are gone, average time a species spends on Earth is 1-10 million years
Background extinction rate
Rate at which extinction occurs gradually, one species at a time
MASS EXTINCTIONS
5 events of large proportions that killed off a huge number of species at once
Best-known mass extinction
Happened 65 million years ago (ended dinosaurs and others)
Evolution
As a general term, means 'change over time'
Gene
A sequence of DNA that codes for a particular trait
Mutation
Changes in DNA
Genetic drift
Biological evolution that occurs by chance
Natural selection
The process by which traits that improve an organism's chances for survival and reproduction
Fitness
Reproductively successful an organism is in its environment
Adaptation
A heritable trait that increases an individual's fitness
Artificial selection
The process of selection conducted under human direction
Extinction
The disappearance of a species from Earth
Natural selection and environment
The connection between natural selection and the environment, as the environment allows organisms with the best adaptations to live, reproduce, and grow the most
Ecologist's consideration
Must consider both speciation and extinction because each contributes to analyzing the diversity of life on Earth
Speciation's effect
New species slowly form over time and increase the total number of species
Organism's habitat
describes the general place it lives
Niche
habitat where organism lives, food it eats, how/when it reproduces, other organisms it interacts with, summary of everything an organism does and when/where it does it
Specialist
extremely good at certain things but struggle to adapt in changing conditions
Generalist
able to live in many places but not as successful in a given situation
Intraspecific competition
multiple organisms of the same species seek the same limited resources
Interspecific competition
multiple organisms of different species seek the same limited resources
Competitive exclusion
very effective competitive species may exclude another species from same resource use entirely
Fundamental niche
full niche of a species
Realized niche
a niche restricted by competition
Resource partitioning
competing species may evolve to occupy only realized niche, adapt to competition by using slightly different resources or shared resources in different ways
Character displacement
resource partitioning leads to evolution of physical traits that reflect their specialized role
Predation
predator hunts/captures/kills/consumes another organism (different species) or the prey
Predator/prey interaction
influences community structure, determines relative numbers of predators/prey
Population cycles
Increase in prey population leads to more food, survival, reproduction for predator; predator population rise leads to lower prey population
Natural selection
process where predators better at getting prey are more successful, leading to evolution of adaptations
Co-evolution
a change in one species leads to changes in the other species in a predator-prey relationship
Herbivory
interaction where herbivores consume plants, affecting plant populations
Parasitism
relationship where one organism benefits at the expense of another
Competition relationship
(-/-) relationship, harmful and beneficial for one and the other (+/-)
Parasitism
A relationship in which one organism, the parasite, depends on another, the host, for nourishment or some other benefit.
Symbiosis
A long-lasting and physically close relationship in which at least one organism benefits.
Herbivory
The interaction in which an animal feeds on a plant.
Mutualism
A relationship in which two or more species benefit.
Commensalism
A relationship in which one species benefits and the other is unaffected.
Niche
Describes its use of resources and its functional role in a community.
Tolerance
The ability to survive and reproduce under changing environmental conditions.
Resource partitioning
The species partition, or divide the resource they use in coming by specializing in different ways.
Predation
The process by which an individual of one species, a predator, hunts, captures, kills, and consumes an individual of another species, the prey.
Coevolution
The process by which two species evolve in response to changes in each other.
Competition
When multiple species compete with each other for the exact same resources, they may adapt to competition by using different resources or using them in different ways.
Realized niche
A portion of the resources that a species can use, limited by competition.
Arms race
A kind of coevolution where each species develops stronger and stronger 'weapons' in response to each other.
Natural selection
The process that does not produce adaptation for a purpose but enables organisms to better survive/reproduce in their environments.
Pollination
An important mutual relationship where bees, birds, bats, and butterflies transfer pollen from flower to flower, fertilizing eggs and providing food.
Mycorrhizae
Symbiotic associations formed between plant roots and fungi, where the plant provides energy and protection while the fungus assists in nutrient absorption.
Ticks
An example of a parasite that attaches to a host's skin, benefiting while harming the host.
Plant defenses
Natural selection leads to the development of defenses against herbivores, such as toxic chemicals, thorns, spines, and irritating hairs.
African moths
An example of a coevolving species with orchid flowers, where the moth's proboscis is adapted to reach the nectar.
Bacteria and human digestive tract
An example of a mutual species interaction where bacteria help digest food, benefiting humans, while also receiving nutrients.
Effect on Species A
The impact of an interaction on the first species involved.
Effect on Species B
The impact of an interaction on the second species involved.
Interaction
The type of relationship between two species, such as commensalism, competition, herbivory, mutualism, parasitism, or predation.
Predator
An individual of one species that hunts, captures, kills, and consumes an individual of another species.
Prey
An individual of another species that is hunted, captured, killed, and consumed by a predator.