QOD 5/1 & 5/4 Over many generations, unrelated or distantly related species may come to resemble each other due to — a) similar environmental factors b) competition with each other c) homologous structural adaptations d) similar genetic mutations

Ecology

Remember… organelles < cells < tissue < organs < organ systems < organism

In addition… organism < population < community < ecosystem

Key Terms A population is made of organisms of the same species in a specific location at a specific time The specific location that a population lives is its habitat The role a species plays in an ecosystem is called its niche ; includes habitat, and interactions with other species Many different species in a habitat make up a community All biotic factors in a habitat as well as all abiotic factors together make an ecosystem

Practice Question The organisms in a typical backyard are likely to include bacteria, grass, shrubs, trees, insects, spiders, birds, and small mammals. Together, all these organisms make up — A.a population B.an experimental group C.a community D.a kingdom

Population Ecology

Populations Population: all organisms of the same species that live in one place at one time Three important features of populations: 1.Density 2.Size 3.Dispersion

Population Density Population density: number of individuals in a given area More dense areas can lead to higher population increase because of higher reproduction rates Can also lead to problems with diseases!

Population Size Population size: number of individuals in a population Limiting factors: Population size can be limited by available resources in the environment; called density-dependent factors Food Water Also limited by density-independent factors that can effect population size regardless of density (randomly) Weather

Population Size Populations are better off larger More genetic variation/diversity Smaller populations can be harmful Natural disasters such as fire or flooding/drought can wipe out all individuals More inbreeding; leads to lower disease resistance because of reduced genetic diversity

Dispersion Dispersion: arrangement of individuals in an area Random: no order Grouped: individuals grouped together Even: individuals spaced evenly

Carrying Capacity Carrying capacity (K): the maximum population size that the environment can handle (because of available resources)

Growth Rates Population growth can follow two growth rates Exponential: bacteriaLogistic: humans

R-strategists R-strategists follow the exponential growth curve Shorter life-span Less maternal care Many offspring Mature quickly Rapid population growth Ex: most pests such as cockroaches, insects, bacteria

K-strategists K-strategists follow the logistic growth curve Longer life-span More maternal care Few offspring Slower maturation Slower population growth Ex: mammals

QOD 5/5 & 5/6 Organisms reproduce following several patterns. Some organisms produce few offspring and provide parental care. Other organisms produce many offspring but provide little or no parental care. Which of the following organisms has the greatest risk of losing a population due to the death of only a few individuals? A.Bacteria B.Flies C.Elephants D.Rats

Ecology Quiz Word bank: trees, rocks, elephant, leaves, rhinoceros, leopard, air, lizard, water, ape, flower, sunlight, lion feces, bird, dead zebra remains 1.List all components from the word bank above that would be considered part of a community. 2.List all components from the word bank above that would be considered part of an ecosystem. 3.List all components from the word bank above that are considered abiotic. 4.Describe a population based on your choice of a component from the word bank above (be specific!)

Community Ecology

Biodiversity Biodiversity is the number of different species in an ecosystem Biodiversity is important in an ecosystem, as many organisms depend on one another Humans often threaten biodiversity by changing ecosystems

Community Interactions Within a community, species interact with one another in many ways Energy flow Symbiosis Succession

Energy Flow There is a flow of energy in ecosystems; all organisms need energy to carry out life processes We use cellular respiration to make that energy! There are different levels of energy, called trophic levels that are included in studying the flow of energy

Producers v. consumers Remember, producers such as plants make their own chemical energy Consumers must consume (eat) other organisms in order to get their energy

Trophic Levels First trophic level: autotrophs Produce energy using the sun (photosynthesis!) Plants, bacteria, algae Second trophic level: herbivores Eat plants, bacteria, algae Have flat, dull teeth Cows, horses Third trophic level: carnivores Eat herbivores Have sharp teeth Lions, snakes, wolves Omnivores can be seen at various trophic levels Eat both autotrophs and herbivores Have both flat dull teeth and sharp teeth Humans, bears

Detritivores and Decomposers Detritivores get their energy from eating the organic wastes and dead bodies of all trophic levels Worms, dung beetles Decomposers decay organic matter in order to absorb nutrients Fungi, bacteria

Food Chain A food chain shows the flow of energy through an ecosystem in a single path

Food Web A food web is more complex than a food chain; shows many paths of energy flow in an ecosystem

Energy Flow Starting from the sun and producers, energy is lost moving down the food chain Much is lost as heat in chemical processes 90% of energy is LOST; 10% of energy moves on!

Energy Pyramid Energy pyramids show the loss of energy through the trophic levels of an ecosystem

Symbiosis Symbiosis is a relationship between two species in an ecosystem. Three important types: 1.Commensalism 2.Mutualism 3.Parasitism

Commensalism +/0 One organism benefits, the other doesn’t benefit but isn’t harmed either.

Mutualism +/+ BOTH organisms benefit.

Parasitism +/- One organism benefits, while the other is harmed. Do NOT confuse this with predation (predator/prey); the host that is harmed needs to continue to live, and does NOT simply get eaten!

Create a Food Web! 1.Choose a location/ecosystem 2.Research & select 10 organisms to include in a food web to include at least two from each trophic level 3.Draw a food web showing the energy flow between your chosen organisms LABEL THE ORGANISMS! Include their scientific names (written properly) & their trophic level (carnivore, omnivore etc.) Be sure to point the arrows in the proper direction!

QOD 5/7 & 5/8 Some plant roots grow with mycorrhizal fungi. The fungi absorb water and minerals and pass them on to the plant and receive carbohydrates from the plant. This is an example of what kind of symbiosis?

Succession Succession is the replacement of species in an ecosystem Pioneer species are the first species to live in a new habitat Usually low-maintenance, fast growing plants & simple species Pioneer species are replaced by other species when the new habitat is ready for other species to get nutrients and support; a climax community occurs when succession is finished Pioneer species>succession>climax community Lichens > grass > weeds > shrubs > trees

Succession Primary succession : succession that occurs where there were no plants before Ex: glacier melts and land is exposed Secondary succession : succession that occurs where there were once plants Ex: abandoned fields

( ) Which order of diagrams would show primary succession in an area that had never before been occupied by living organisms? D, B, C, A C, A, B, D A, C, B, D B, A, C, D

( ) Each drawing represents different stages in community succession within the state of Virginia. Which of the following drawings represents the climax community in this succession pattern? F G H I