Miss Hillemann Biology I Neshaminy High School Ecology Miss Hillemann Biology I Neshaminy High School

Ecology Study of interactions among organisms and between organisms and their environment. Biotic factors: prokaryotes, protists, fungi, plants, and animals Abiotic factors: nonliving physical and chemical conditions

Biotic & Abiotic Factors at 5 Levels Organisms: smallest unit of ecological study. Ex: sweetlip fish in a coral reef Population: group of individual organisms of the same species living in a particular area. Ex: group of sweetlip fish Communities: all of the organisms inhabiting a particular area.Ex: coral reef is home to fish, coral, animals, microscopic algae and other living things

5 Levels (cont’d) Ecosystem: includes abiotic and biotic factors in an area. Ex: coral reef living creatures, water, sunlight. Biosphere: sum of all Earth’s ecosystems Not spread out evenly. Patchiness creates different habitats or specific environments for organisms to live.

Key Abiotic Factors Sunlight- heats the Earth Water- essential to all life Temperature- (0 to 50°C) narrow range for most organisms Soil Wind Severe disturbances

Biomes Biomes- Terrestrial ecosystems that cover large regions of Earth Tropical Forest: occur near the equator where temperatures are warm year round Rain forest: 350 cm of rain yearly. Ideal growing conditions for a variety of plants Madagascar- 8,000 species of flowering plants

Biomes Savanna- grasslands with scattered trees (Africa, Australia, S. America). Usually a warm climate with alternating wet and dry seasons Desert: land areas receiving less than 30 cm of rain per year.

Biomes Chaparral- temperate coastal biome dominated by dense evergreen shrubs Climate consists of mild, rainy winters and hot, dry summers Ex: California Temperate Grasslands: deep, nutrient-rich soil that supports a variety of grass species and plants Ex: S. Dakota (drier), Kansas (wetter)

Biomes Temperate Deciduous Forest- full of trees that drop their leaves each year. Cold winters and hot summers Ex: maple, oaks, beeches, and hickory Coniferous Forest: cone-bearing evergreens Cold winters, heavy snowfall Ex: pine, spruce, fir, hemlock

Biomes Tundra: bitterly cold temperatures and high winds Permafrost: permanently frozen subsoil

Limits to Population Growth Carrying capacity- # of organisms in a population that the environment can maintain with no net increase or decrease Limiting Factor: a condition that can restrict a population’s growth Ex: space, disease, availability of food

Factors Affecting Population Growth Density-dependent factors: availability of high-quality food  more dense Density-independent factors: extreme weather conditions (hurricanes, blizzards, ice storms, droughts) effect a population The same regardless of its size

Energy Flow Producers- plants obtain energy from sun Consumers- organisms that obtain energy from producers and other consumers Decomposers- breakdown organic material and put nutrients back into environment

Food Chains Producers- photosynthetic consumers Herbivores- eat plants Carnivores- eat other consumers Omnivores- eat both producers and consumers

Consumer classification Consumers are categorized by their position in the food chain. Primary- feeds directly on producer Secondary- eat primary consumer Tertiary- eat secondary consumers Quaternary- eat tertiary consumers (usually low)

Food Web

Carbon Cycle CO2 in atmosphere- used by plants in photosynthesis Consumers eat producers and release CO2 during cellular respiration

Nitrogen Cycle N2 in atmosphere converted to NH3 by bacteria NH3 becomes NH4+ in soil Bacteria in soil convert NH4+ to NO3- Denitrifying bacteria convert NO3- to N2 (back to atmosphere)

Water Cycle H2O vapor in atmosphere condensed Precipitation Groundwater Absorbed by plants Transpiration and evaporation put H2O vapor back in atmosphere

Energy Flow vs. Chemical Cycles Energy flows in one direction. Chemicals recycle.

Competition Between Species Members of a population may compete for limited resources in the environments. Competition within a single species limits the growth of the population. Within a community, interspecific competition (competition between species) takes place when 2+ species rely on the same limited resource.

Competitive Exclusion If 2 species are so similar in their requirements that the same resource limits both species’ growth, one species may succeed over the other.

Niches A niche includes an organism’s habitat, its food sources, the time of day it is most active, and other factors specific to its way of life. No 2 species can occupy the same niche in the same habitat at the same time because of the competitive exclusion principle.

Symbiotic Relationships Symbiotic relationship- close interaction between species in which one of the species lives in or on the other. Parasitism- one organism benefits; the other is harmed. Ex: blood-sucking mosquito Ex: tapeworm that live and feed in the intestines of larger organisms

Symbiotic Relationships (cont’d) Mutualism- both organisms benefit Ex: a flower’s nectar provides the insect with food and the insect pollinates the flower Commensalism- one organism benefits; the other is neither harmed nor helped Ex: spider crab places seaweed on its back to camouflage it from predators, but the seaweed is not significantly affected

Global Warming CO2 allows sunlight to pass but traps heat “Greenhouse effect”- atmospheric gases act like the glass windows of a greenhouse As levels of CO2 and other “greenhouse gases” rise, average temperatures on Earth rise  global warming