Math Fundamentals Quiz 10th Class

Populations and Communities

• Ecosystems are complex interactions between organisms and their environment.
• Populations are groups of individuals of the same species.
• Communities are groups of populations.
• Populations and communities interact with their environment.
• Population size can change over time.
• Researchers use sampling techniques to study population growth or decline.

Populations as Interacting Groups

• Populations consist of organisms of the same species living in the same area.
• Members of a population typically breed with one another.
• Reproductive isolation separates different populations of the same species.
• A population is a group of individuals that live in the same area at the same time and can interbreed.

Estimating Population Size

• Estimating population size is often more practical than counting every individual.
• Random sampling techniques are crucial to avoid bias.
• Sampling error is a common issue in population estimation.
• Researchers often use methods like random sampling with quadrats or mark-and-recapture.

Sampling Sessile Organisms

• Systematic sampling involves measuring or counting organisms at regular intervals.
• Random sampling involves arbitrarily chosen zones of a geographic distribution.
• Sampling error is inevitable in estimating population size.
• The standard deviation of the mean of a sample provides a measure of variation.

Sampling Motile Organisms

• The capture-mark-release-recapture method is used to estimate the population of motile organisms.
• The number of marked individuals recaptured in a second sample provides an estimate of the total population.
• Certain assumptions are crucial to the validity of this method (closed population, equal chance of capture, no in- or emigration).

Carrying Capacity

• Carrying capacity (K) is the maximum population size an environment can support.
• Some factors that limit population growth are food availability, water, presence of predators, and diseases.
• Resources like food and space can limit population size.

Negative Feedback

• Negative feedback mechanisms help populations stay within their carrying capacity.
• Density-dependent factors tend to regulate population size towards carrying capacity (e.g., increased competition for resources, disease spread).
• Density-independent factors affect both large and small populations equally (e.g., climate change, natural disasters).

Population Growth Curves

• Population growth curves often show exponential growth initially.
• The transition phase slows population growth.
• The plateau phase occurs when the population reaches carrying capacity.

Modeling Growth Curves

• Population growth curves can be modeled.
• The sigmoid curve is an idealized representation.

Communities

• Communities comprise all populations in an area.
• Interactions between populations (e.g., competition, cooperation).

Intraspecific and Interspecific Relationships

• Intraspecific relationships refer to interactions within the same species (cooperation and competition).
• Interspecific relationships refer to interactions between different species (e.g., predation, competition, mutualism).
• Interspecific competition occurs when two species compete for the same resources.

Predator-Prey Relationships

• Predator-prey relationships can affect the size of populations of both predator and prey.
• Predator-prey relationships exhibit cycles.
• Predation, along with other factors such as food availability and disease, controls population size.

Endemic and Invasive Species

• Endemic species are found only in a specific geographic area.
• Invasive species are introduced from somewhere else and can outcompete native species.

The Chi-Squared Test

• The chi-squared test can be used to investigate whether two species tend to occur together.
• The presence or absence of two species in sampling sites can indicate whether competition exists.

Energy Flow and Matter

• Organisms require energy for biological processes.
• In ecosystems, matter can be recycled but energy cannot (law of conservation to mass and the 2nd law of thermodynamics).
• Photosynthesis and cellular respiration are critical for energy transformations.

Trophic Levels & Cycles

• Trophic levels represent energy transfer in ecosystems.
• Food chains and food webs illustrate the connections between organisms.
• Biological concepts like autotrophs and heterotrophs are part of the trophic levels structure.
• The carbon cycle shows how carbon moves through ecosystems.