Habitats, Biomes, & Populations

What is a habitat?

A physical area where a species is found, including information about geographical area, physical location, food, water, shelter availability, ecosystem, biotic and abiotic factors.

What are abiotic factors?

Nonliving aspects of the environment, such as soil, pH, light, water, inorganic nutrients, and space.

What are biotic factors?

Living components of the environment, including factors like competition, symbiosis, and predators.

What are limiting factors?

Factors that affect communities by determining which species are present and how organisms adapt to their environment.

Provide an example of a plant found on the sand dunes and its adaptations.

Marram Grass, which has long dense roots, salt tolerance, and drought tolerance.

What is an example of a plant found in the mangrove forest and its adaptations?

Mangrove Trees, which have pneumatophores, stilt roots, and are halophytes.

What is the method used for transects?

A method to determine the effects of limiting factors on a sample of organisms in an area, commonly using line transects.

What are the conditions needed for coral reef formation?

Water depth of 2-45m, stable salinity, temperature between 23-29°C, pH of 8-8.4, and clear water.

List human activities that destroy coral reefs.

Global warming, overfishing, pollution, and coastal development.

What shapes biomes?

Biomes are shaped by common environmental conditions, particularly temperature and precipitation.

What distinguishes biomes from ecosystems?

Biomes are larger and more broadly defined, while ecosystems are smaller and more specifically defined.

What are the characteristics of the desert biome?

Characteristics of the desert biome include limited water supply, extreme temperature variations, and specialized plant and animal life adapted to arid conditions.

What are the adaptations of the tropical rainforest biome?

Adaptations in the tropical rainforest biome include broad leaves to capture light, shallow root systems, and rapid growth rates.

What is a species?

A group of individuals that produce fertile offspring.

What is a population?

A group of organisms of the same species found in a specific area that share a common gene pool and are generally reproductively isolated.

Describe the three distributions of species within a population.

Random: plentiful resources & little social interaction; Uniform: intraspecific competition; Clumped: social and most often seen.

List the four factors that influence population size.

Natality (birth), mortality (deaths), immigration (move in), and emigration (move out).

What is carrying capacity?

The maximum population size that the environment can sustain, denoted as 'K'.

What is population density?

The number of individuals per unit area, indicating how packed organisms are, which can impact population size.

What are density dependent factors?

Factors that impact population size as density increases, such as competition, predation, and disease.

List density dependent factors.

Factors that impact population size regardless of density, such as natural disasters or climate changes.

What are the two types of population growth curves?

Exponential Growth Curve (ideal conditions and unlimited resources) and Logistic Sigmoid Growth Curve (more realistic, accounting for limiting factors).

What does the sigmoid growth curve represent?

It illustrates a population's growth slowing down as it approaches its carrying capacity due to limited resources.

Give an example of sigmoid growth.

Sheep introduced to Tasmania, where their population initially grows rapidly and then stabilizes around the carrying capacity.

What are the two methods to estimate population size?

Mark-Recapture Method and Quadrat Sampling.

What distinguishes sessile from motile organisms?

Sessile organisms are attached to a substrate and cannot move freely (e.g., barnacles), while motile organisms can move freely (e.g., fish).

What is quadrat sampling?

A method involving randomly placing quadrats in a study area to estimate population density by counting individuals within each quadrat.

What is the Lincoln Index?

A method called 'capture - mark - release - recapture' used to estimate population size.

What is the formula for Lincoln Index?

N = (n1 * n2) / m2, where N is estimated population size, n1 is marked individuals in the first sample, n2 is total individuals captured in the second sample, and m2 is marked individuals recaptured.

What is the common name for the Lincoln Index?

Capture - mark - release - recapture.

What is the significance of standard deviation in population studies?

It indicates the variability in data; high standard deviation shows major differences across the sample area, while low standard deviation indicates uniform abundance