Biology Unit 6 Assessment - Ecology

How do biotic and abiotic factors impact one another in the biosphere?

*Abiotic factors determine what kind of biotic factors can be present.* For example, frigid climates will not support lizards and other cold blooded animals. Instead animals like blubbery whales and polar bears are better suited. *In addition, biotic factors impact abiotic factors.* Microbes and plant life in a lake determines the different factors of the water (sunlight level, acidity, murkiness, etc.). It is a cycle.

What are six examples of abiotic factors in an environment? Biotic?

*Abiotic:* Temperature, air currents, water currents, sunlight, soil, rainfall *Biotic:* fish, algae, interactions between organisms, migratory animals, microscopic animals, birds

Be able to read a scenario about an ecosystem and explain how it impacts a food chain or food web.

*Example:* There is a drought in the Pacific Ocean and many of the plants have to fight for room and die. The smaller no longer have their food source and therefore die off eventually leading to a chain reaction of the decrease of many species.

What is the difference between exponential growth and logistic growth? Be able to identify each based on a graph.

*Exponential Growth:* occurs when the individuals in a population reproduce at a constant rate; under IDEAL conditions with unlimited resources, population will grow exponentially *Logistic Growth:* occurs when population growth slows or stops following a period of exponential growth; happens when the population has reached the carrying capacity

Label and describe the three climate zones on earth.

*Polar:* characterized by a lack of warm summers and very cold winters. Every month in a polar climate has an average temperature of less than 10 °C (50 F) *Temperate:* Average yearly temperatures in these regions are not extreme, not burning hot nor freezing cold. Temperate means moderate. Have four seasons: summer, autumn, winter and spring. *Tropical:* non-arid climate in which all twelve months have mean temperatures of at least 18 °C (64 °F). In tropical climates there are often only two seasons: a wet season and a dry season.

Which succession takes more time? Why?

*Primary succession* takes more time because soil needs to be created

Compare and contrast primary and secondary succession.

*Primary:* occurs on newly exposed surfaces (bare rock, no soil) *Secondary:* occurs when a disturbance does not destroy the soil *Both:* ecosystems grow and become more complex; pioneer species will emerge; gradual change

What are the four major human population growth events? When did they occur? What happened to the population?

1. *AGRICULTURE:* 4000 BCE, led to population decrease 2. *IRRIGATION:* 2000 BCE, led to population increase 3. *BLACK DEATH:* 1347-1352, led to a dramatic decrease in population 4. *INDUSTRIAL REVOLUTION:* 1800's, led to a dramatic population increase

List, describe and give an example of each type of density-dependent limiting factor.

1. *Competition:* overcrowding leads to competition for food, space, water, and other essential resources; e.g. a squirrel competing with another for the same tree 2. *Predation:* one of the best methods of population control; predator-prey relationship; e.g. a fish and a shark 3. *Parasitism:* spread from individual to individual quickly in large populations; e.g. tapeworms 4. *Disease:* spread quickly and easily through large populations; e.g. smallpox

What are the characteristics of populations?

1. *Geographic distribution (Range):* area where a population is found 2. *Density:* number of individuals per unit area 3. *Growth rate:* how fast or slow a population grows over time 4. *Age structure:* the number of individuals of each gender at each age; can be used to predict population growth

List, describe and give an example of each type of heterotroph.

1. *Herbivore:* consumer plants; e.g. pandas 2. *Carnivore:* consumer meat/other organisms; e.g. lion 3. *Omnivore:* consume plants AND meat; e.g. grizzly bear 4. *Detritivore:* consumer dead organic mater; e.g. vulture 5. *Decomposer:* break down organic matter; e.g. mushrooms

List and describe at least 3 climate factors that shape ecosystems.

1. *Latitude:* A places distance from the Earth's equator (affects temperature) 2. *Elevation:* The distance up or down from sea level 3. *Ocean Currents:* Movement of water 4. *Continental Landmasses:* Continents

List, describe and give an example of each type of symbiotic relationship.

1. *Mutualism:* symbiotic relationship in which both organisms benefit; e.g. bees and flowers 2. *Parasitism:* symbiotic relationship in which one organism benefits at the expense of another; e.g. fleas and dogs 3. *Commensalism:* symbiotic relationship in which one organism benefits and the other is neither helped nor harmed; e.g. barnacles and whales

What are the levels of organization in the biosphere in order from smallest to greatest?

1. *Organism:* individual organisms 2. *Population:* organisms that share a habitat 3. *Community:* a group of interacting populations that occupy the same geographic region 4. *Ecosystem:* a biological community and all the non-living factors that affect it 5. *Biome:* a group of ecosystems that share the same climate and have similar types of communities 6. *Biosphere:* The highest level of organization; it is all regions of Earth that support life

Explain the difference and include an example of each, between habitats and niches.

A habitat is the *general place where an organism lives* and a niche is the *range of physical and biological conditions in which a species lives and the way the species obtain what it needs to survive and reproduce.* *Examples:* Habitat: deserts, marshes, rivers Niche: a garden spider is a predator that hunts for prey among plants, while an oak tree grows to dominate a forest canopy, turning sunlight into food. The role that a species plays is called its ecological niche

What is an ecological equivalent? Give 3 examples.

An ecological equivalent is *a different species that occupies a similar ecological niche in a similar ecosystem in a different part of the world.* *Examples:* - The mountain goat (north America) and the Ibex commonly (Alps of southern Europe) - The kangaroo of Australia and the pronghorn antelope of north America - Mountain lions and African lions

Explain how competition can impact evolution.

Competition between different species may lead to evolution. It causes species to "outcompete" the other because of the Competitive Exclusion Principle. Competition can lead to extinction (ends evolution) and can also force organisms out of their environment and into a new one (leads to evolution).

Describe and give an example of density-independent limiting factors.

Density-independent factors *affect all populations in similar ways regardless of size*. Response to these factors result in a dramatic decrease of population size. The major example is *natural disaster*.

What is the human impact on the water cycle?

Surface runoff occurs when excess stormwater or meltwater flows over the surface of the earth. Urbanization and human influence can lead to surface runoff contributing to water pollution.

Be able to discuss the plague. (causes, the bacteria, types, population killed, symptoms, etc.)

The *BLACK DEATH* was comprised of three plagues, all caused by the same bacteria (Yersinia pestis); killed 1/3 of the world's population: - *The Bubonic Plague:* 40-60% morality in 7-10 days; symptoms include buboes, fever, chills, nausea - *The Septicemic Plague:* 90-100% morality in 5-7 days; symptoms include fever, chills, nausea - *The Pneumonic Plague:* 99-100% mortality in 3 days; symptoms include fever, chills, nausea

What do the arrows in a food chain or food web represent?

The flow of energy

What is the human impact on the carbon cycle?

The human impact of pollution can lead to the *greenhouse effect*. Our use of fossil fuels contributes to extremely high CO2 levels (more than can be removed by oceans and photosynthetic organisms).

What is demography?

The scientific study of human population growth

What are the cycles of matter? What are the important components of each.

1. *The Water Cycle:* five basic steps: condensation, precipitation, infiltration (of the soil), runoff, and evapotranspiration 2. *The Carbon Cycle:* autotrophs remove atmospheric CO2 during photosynthesis; this CO2 is then returned to the environment through decaying organisms and fossil fuels 3. *The Nitrogen Cycle:* although nitrogen is very abundant in the atmosphere, it is largely inaccessible in this form to most organisms; nitrogen becomes available to plants through fixation; animals then get nitrogen by eating plants, then that nitrogen is released back into the environment through decomposition.

How do you identify trophic levels in a food chain or food web?

1. *Trophic Level 1:* consists of primary producers such as plants 2. *Trophic Level 2:* herbivores 3. *Trophic Level 3:* predators 4. *Trophic Level 1:* carnivores or apex predators

Be able to read and analyze an energy pyramid.

Energy pyramids show the relative amount of energy available to each tropic level; the more levels that exist between a producer and a top-level consumer, the less energy that remains from the original amount. Remaining energy is shown by the numbers on the side of the pyramid.

How do you find population density?

Formula: *population density = the number of individuals/unit area* Ex. 4500 E.coli populate an area that is 10cm2 --> the population density = 450 E.coli/cm2

What types of events would cause secondary succession?

Forrest fires, harvesting, hurricanes, etc.

How do human impact food webs? Be able to use the Chesapeake Bay as an example.

Humans are dominant consumers. They affect food webs through energy production and agriculture, pollution, habitat destruction, overfishing and hunting. Also, their demands for food and shelter along with population growth, affect soil and aquatic ecosystems. *Chesapeake Bay:* Larger fish accumulate toxins in their tissues when they eat contaminated smaller organisms (which are contaminated due to pollution). Birds, other wildlife and even humans may eat contaminated fish, allowing the contaminants to continue to move through the food web. Also, overfishing may lead to the decline in the population of one of the ecosystem's trophic levels --> starvation of their predators, overpopulation of their prey.

What is the Competitive Exclusion Principle?

No two species can occupy the same niche in the same ecosystem at the same time.

What is the human impact on the nitrogen cycle?

The way humans use and dispose of *fertilizers* lead to increased nitrogen in the ground which affects the nitrogen cycle.