Bio test 4 definitions

natural selection: The process by which organisms better adapted to their environment tend to survive and produce more offspring. It is the only process that promotes adaptation

artificial selection: The process by which humans select traits they find desirable and breed organisms to enhance those traits. Human choice is a large portion of the environment, favoring traits of human interest 

evolutionary adaptation: A trait that increases an organism's ability to survive and reproduce in its environment. Adaptations arise through the process of natural selection 

Homology: ​​Similarity in characteristics resulting from shared ancestry. Homologous structures are anatomical features that are similar in different species because they were inherited from a common ancestor.

vestigial structures: Anatomical features that are present in an organism but have lost their original function through evolution. These structures are remnants of features that were functional in the organism's ancestors.

Population: A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring.

gene pool:  The total collection of genes and alleles in a population. It represents the genetic diversity available for natural selection to act upon.

genetic drift: A change in the gene pool of a small population due to chance. It can lead to significant changes in allele frequencies over time ​

gene flow: The transfer of alleles or genes from one population to another. It occurs when individuals from different populations interbreed.

sexual selection: A form of natural selection where individuals with certain traits are more likely to obtain mates and reproduce. Competition occurs within a species for access to mates 

relative fitness: The contribution an individual makes to the gene pool of the next generation relative to the contributions of other individuals. It is a measure of reproductive success 

directional selection: a mode of natural selection that favors one extreme phenotype over others, causing a shift in the population's traits. This type of selection is common when the environment changes or when organisms migrate to a new habitat. For example, if a population of mice lives in an area where the landscape becomes shaded by trees, darker mice may become less noticeable to predators. As a result, the population's fur color shifts towards the darker end of the spectrum.

disruptive selection: A type of natural selection that. favors extreme phenotypes over intermediate ones. Imagine a population of mice living in a patchy environment with both light and dark rocks. In this scenario, mice with very light or very dark fur have a survival advantage because they blend into their respective backgrounds, avoiding predators

stabilizing selection:  A type of natural selection that favors intermediate variants and acts against extreme phenotypes. It reduces variation and maintains the status quo for a particular trait

Ecology: Ecology is the study of the interactions living things have with each other and with their environment. It focuses on describing interactions that affect the living world, rather than working on behalf of the environment ​

Population: A population is a group of individuals of a single species that occupy the same general area. Individuals in a population rely on the same resources, are influenced by the same environmental factors, and are likely to interact and breed with one another 

Community: A community consists of all the different species that live together in a particular area. It includes all the populations of different species that interact within a specific environment

Ecosystem: An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system. These biotic and abiotic components are linked together through nutrient cycles and energy flows ​

Biosphere: The biosphere is the global sum of all ecosystems. It includes all living beings and their relationships, including their interactions with the elements of the lithosphere, hydrosphere, and atmosphere 

biotic factors: Biotic factors are the living components of an ecosystem. These include plants, animals, bacteria, fungi, and any other living things that affect the ecosystem.

abiotic factors: Abiotic factors are the non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Examples include sunlight, temperature, wind, water, and soil.

Phytoplankton:  Phytoplankton are microscopic marine algae that form the base of the aquatic food web. They are primary producers, meaning they produce their own food through photosynthesis and provide energy for other marine organisms.

Zooplankton: Zooplankton are small, often microscopic animals that float or drift in water. They feed on phytoplankton and are an important food source for larger marine animals.

primary production: Primary production is the process by which organisms produce organic compounds, particularly through photosynthesis. It is the foundation of the food web, as it provides the energy that fuels all other organisms in the ecosystem.

carbon footprint: A carbon footprint is the total amount of greenhouse gases, including carbon dioxide and methane, that are generated by our actions. It is usually measured in units of carbon dioxide equivalents and is used to understand the impact of human activities on climate change.

Estuary: a coastal area where freshwater from rivers and streams meets and mixes with saltwater from the ocean. Characteristics: high nutrient levels, variable salinity, biodiversity (including fish, birds and invertebrates), and they act as buffer zones (protect from storm surges and flooding) 

intertidal zone: the area between high tide and low tide along coastlines. Characteristics: exposure to air and water (organisms adapt to being submerged in water and exposed to air), tidal influence (experience regular changes due to the tides), diverse habitats, and unique adaptations (to survive the harsh conditions). 

Wetlands: are areas where water covers the soil or is present near the surface for significant periods. Characteristics: water saturation, vegetation (dominated by water-tolerant plants like mangroves), biodiversity (amphibians, birds, insects), and ecosystem services (provide important services such as water filtration, flood control, and habitat for wildlife). 

tropical forests: dense forests located near the equator, characterized by high rainfall and warm temperatures. Characteristics: high biodiversity (plants, animals, and microorganisms), dense canopy, warm and humid climate, rapid nutrient cycling (due to the decomposition of organic matter). 

Savannas: Warm temperatures year-round with seasonal rainfall variations. Dominated by grasses with scattered trees. Found in Africa, South America, and Australia.

Deserts: Low and unpredictable rainfall, with temperatures ranging from 7 to 23°C.

Chaparrals: experience mild, rainy winters and hot, dry summers. This climate is influenced by cool ocean currents circulating offshore.

age structure of a population: refers to the number of individuals in different age groups within a population. Understanding the age structure can provide insights into social conditions and help predict future population growth. For example, knowing the proportion of the population that is at or under reproductive age can indicate the potential for population increase. 

survivorship curve: A survivorship curve describes how soon members of a species tend to die within their lifespan. There are three idealized types of survivorship curves: Type I (Late loss): Most individuals live until old age, Type II (Constant loss): Individuals die at all ages, Type III (Early loss): Most individuals die at a young age

life history: refers to the traits that affect an organism's schedule of reproduction and survival. These traits include the age at first reproduction, the number and size of offspring, and the amount of parental care provided.

opportunistic life history (r-Selected Species): These species are characterized by their small size, short lifespan, and high reproductive rate. They produce many offspring but provide little or no parental care. Their population size is limited by the reproductive rate (r) and is relatively unstable. Examples include insects and many annual plants

equilibrial life history (K-Selected Species): These species are typically larger, have longer lifespans, and produce fewer offspring. They invest significant parental care in their offspring. Their population size is limited by the carrying capacity (K) and is relatively stable. Examples include elephants and humans

exponential population growth: This type of growth occurs when the number of new individuals added to a population is proportional to the number of individuals already present, resulting in a J-shaped growth curve. It is common in populations with abundant resources and minimal environmental resistance

carrying capacity (K): This is the maximum population density of a given species that can be sustained within a defined geographical area over an extended period. It is determined by the availability of resources and environmental resistance factors that limit population growth

limiting factors: are environmental conditions that restrict the growth, abundance, or distribution of a population within an ecosystem. These factors can be biotic, such as competition for food and mates, or abiotic, such as temperature and water availability. Can help determine carrying capacity.

logistic population growth: occurs when the growth rate of a population decreases as the population size approaches the carrying capacity of the environment. This type of growth is characterized by an S-shaped curve, where the population initially grows exponentially but levels off as resources become limited and environmental resistance increases. 

density-dependent factors: are factors that affect the population growth in relation to the population density. As the population density increases, these factors become more pronounced and can include: Competition for food, mates, and nesting sites;Spread of disease;Predation 

density-independent factors: are factors that affect population growth regardless of the population density. These factors can include:Natural disasters such as fires and storms; Habitat destruction by human activities; Seasonal changes in weather

invasive species: are non-native organisms that, when introduced to a new environment, can cause harm to the local ecosystem, economy, or human health.

population momentum: refers to the continued growth of a population after fertility rates have declined to replacement level. This occurs because a large proportion of the population is still in their childbearing years, leading to a high number of births despite lower fertility rates.

ecological footprint: a measure of the amount of land and resources required to sustain an individual's or a nation's consumption patterns. It includes the resources needed for food, fuel, water, housing, and waste disposal. 

Biodiversity: refers to the variety of life in a particular habitat or ecosystem. It includes the diversity of species, genetic variation within those species, and the variety of ecosystems themselves. Biodiversity is crucial for ecosystem stability and resilience, as it allows for a wide range of organisms to interact and support each other in various ways

Competition: the interaction between organisms or species that vie for the same resources in an environment, such as food, space, or light. This can occur within a species (intraspecific competition) or between different species (interspecific competition). Competition can influence population dynamics and the distribution of species within an ecosystem.

Predation: an ecological interaction where one organism, the predator, hunts and consumes another organism, the prey. This interaction is crucial for maintaining the balance of ecosystems, as it helps regulate prey populations and can drive evolutionary changes in both predator and prey species. Predation can also influence the structure and diversity of communities within an ecosystem. 

Parasitism: a type of interaction where one organism, the parasite, benefits at the expense of another organism, the host. The parasite derives nutrients and shelter from the host, often causing harm to the host in the process. Examples include ticks feeding on mammals and tapeworms living in the intestines of animals.​

Commensalism:  an interaction where one organism benefits while the other organism is neither helped nor harmed. The benefiting organism gains resources or shelter without affecting the other organism. An example is barnacles attaching to whales; the barnacles benefit by gaining mobility and access to food, while the whale is unaffected. 

Mutualism:  a type of interaction where both organisms involved benefit from the relationship. Each organism provides resources or services that are beneficial to the other. Examples include bees pollinating flowers while obtaining nectar and ants protecting aphids in exchange for the honeydew they produce.

ecological niche: refers to the role and position a species has in its environment, including all its interactions with the biotic and abiotic factors. It encompasses how a species meets its needs for food and shelter, how it survives, and how it reproduces. A niche includes the species' habitat, its place in the food web, its behaviors, and its interactions with other species. 

Herbivory: a form of predation in which an organism, known as an herbivore, feeds on plants. Herbivores play a crucial role in ecosystems by controlling plant populations, which in turn affects the structure and composition of the community. This interaction is a key component of community and ecosystem ecology

trophic level: : A trophic level refers to the position an organism occupies in a food chain. It represents the feeding level of an organism, starting from primary producers at the base to apex predators at the top. Each level indicates the flow of energy and nutrients from one group of organisms to another.

Autotroph: Autotrophs, also known as producers, are organisms that produce their own food using light, water, carbon dioxide, or other chemicals. They are capable of photosynthesis or chemosynthesis. Examples include plants and algae, which use photosynthesis to convert solar energy into chemical energy stored in carbohydrates. 

Heterotroph:  Heterotrophs, also known as consumers, are organisms that cannot produce their own food and rely on other organisms for nutrition. They obtain energy by consuming plants, animals, or decomposing organic matter. Examples include animals, fungi, and many bacteria. 

Producers: Producers are organisms that create their own food through processes like photosynthesis or chemosynthesis. They form the base of the food chain and provide energy for all other trophic levels. In the context of photosynthesis, producers include plants and algae, which convert solar energy into chemical energy stored in sugars. 

primary consumers (or herbivores): These are organisms that eat producers, such as plants and algae. Examples include grasshoppers, ants, and rodents that consume plant matter.

secondary consumers (carnivores): These organisms eat primary consumers. On land, they include small mammals like mice, birds, frogs, and spiders. In aquatic environments, small fish that eat zooplankton are secondary consumers.

tertiary consumers: These are predators that eat secondary consumers. Examples include snakes that eat mice and other secondary consumers.

quaternary consumers: These are top-level predators that eat tertiary consumers. Hawks in terrestrial communities and killer whales in marine environments are examples.

Decomposers: organisms that break down dead or decaying organisms, and in doing so, they carry out the natural process of decomposition. 

food chain: a linear sequence of organisms through which nutrients and energy pass as one organism eats another.

food web: a complex network of interconnected food chains within an ecological community.

biological magnification: also known as biomagnification, refers to the increasing concentration of toxic substances in organisms at each successive level of the food chain. 

Biogeochemical cycle: refers to the movement of chemical elements and compounds between living organisms and the physical environment. These cycles include the water, carbon, nitrogen, phosphorus, and sulfur cycles, which are essential for life on Earth

abiotic reservoir:  a non-living storage area for elements or compounds that are part of biogeochemical cycles. Examples include the atmosphere, bodies of water, and soil.

Producer: also known as autotrophs, are organisms that produce their own food through processes like photosynthesis. They convert solar energy into chemical energy, forming the base of the food chain

Consumer: or heterotrophs, are organisms that rely on other organisms for food. They obtain energy by consuming producers or other consumers. 

Decomposers: are organisms that break down dead or decaying organic material, recycling nutrients back into the ecosystem. They play a crucial role in maintaining the flow of energy and matter through ecosystems.

Greenhouse effect: a natural process that warms the Earth's atmosphere. It works similarly to a greenhouse used for growing plants. Sunlight passes through the Earth's atmosphere, warming the surface. This heat is then radiated back towards space, but greenhouse gases trap some of this heat, keeping the Earth warm.

Greenhouse gases: gases that absorb and emit infrared radiation, leading to the greenhouse effect, which warms the Earth's atmosphere.