Ecology

AP Biology

Ecology Background Terms• ____________-a group of individuals of the same species

living in the same area• ____________- a group of populations in the same area• ____________- the interrelationships between the

organisms in the community and their physical environment

• ____________- all of the ecosystems on earth • ____________- a place where an organism lives • ____________- describes all the biotic (living) and abiotic

(nonliving) resources used by an organism in the environment- their place in the ecosystem is their niche

Population Ecology• The study of the growth, abundance and distribution of populations.

Described by:

• ____________ of a population- symbolically represented by N- is the total number of individuals in the population

• ____________- the total number of individuals per unit of space

• ____________- how individuals in the popuilation are distributed. They may be clumped (humans in cities), uniform (trees in an orchard), or random (trees in some forests)

• ____________ structure- the abundance of individuals of different ages

• ____________ curves- describe the mortality (death) of individuals during different parts of their lifetimes

Age Structure Pyramids

Survivorship Curves• Type I curves- species in which most individuals

survive to middle age, after that mortality is high. EX-

____________• Type II curves- species in which the length of

survivorship is random- the likelihood of death is the

same at any age. EX- ____________• Type III curves- species in which most individuals die

young. EX- _____

Terms Describing Population Growth • ________________maximum growth rate of

the population under ideal conditions• ________________maximum size of the

population in a particular habitat• _________________anything that limits the

size of a population. They can be: – Density ____________- limit the size of a

population based on how close the organisms are to each other. EX- diseases

– Density ____________- limit the size of a population regardless of how close they live to each other EX- natural disasters

Population Growth • ____________Grow

th- occurs when a the reproductive rate is greater than zero. On a graph, exponential growth forms a J-shaped curve.

• ____________Growth- occurs when limiting factors restrict the size of the population to the carrying capacity of the habitat. On a graph, it forms an S-shaped curve

Reproductive Strategies• There are two types:

1. ____________species- exhibit rapid exponential growth. This type of reproductive strategy is characterized by opportunistic species- such as grasses and many insects- that quickly invade a habitat, quickly reproduce, and then die. They produce many offspring that are small, mature quickly and require little (if any) parental care. 2. ____________species- population size remains relatively constant at the carrying capacity. Species of this type, such as humans, produce a small number of relatively large offspring that require extensive parental care.

Predator Prey Relationships

Human Population Growth• A thousand years ago the human population began

undergoing exponential population growth. This was made possible by: – Increases in ____________supply due to domesticating

animals and plants, as well as technological advances in farming (such as enriching soil with nitrogen)

– Reduction in ____________- advances in medicine, such as antibiotics, vaccines, and proper hygiene

– Water ____________and sewage systems- reduce health hazards

– Expansion of ____________- better housing, warmer clothing, access to energy for heating/cooling/cooking, transportation

Human Population Growth

Community Ecology • Is concerned with the interaction of populations. One form

of interaction is interspecific competition (between two different species). The following are ways this competition can be resolved: – ________________________Principle- when two species

compete for exactly the same resource (or occupy the same niche) one species will eventually outcompete the other. No two species can occupy the same niche

– ________________________-some species coexist in spite of apparent competition for the same resources. This is because they actually pursue slightly different niches. EX- five species of birds coexist in the same type of tree by feeding on insects in different regions of the tree.

Resource Partitioning

Niches• ____________Niche- the niche an organism occupies in

the absence of competing species

• ____________niche- the actual niche the organism

occupies when competition is present

Predation• Can be categorized as follows:

– A true ____________kills and eats another animal

– A ____________spends most or all of its life living on another organism (the host)

– A ____________is an insect that lays its eggs on a host and the larvae each the ost when they hatch

– A ____________is an animal that eats plants. Some may consume the entire plant.

Symbiotic Relationships• ____________- when two species live together in close

contact. There are different types: • ____________- both species benefit. EX- acacia trees provide

food and shelter for ants. The ants kills any insects, fungus, or vegetation on or near the tree

• ____________- one species benefits, the other is unaffected EX- birds nest in trees

• ____________- one species benefits, the other is harmed EX- tapeworms

Coevolution • In the contest between predator and prey, some have evolved

unique heritable characterists:

– ____________compounds- toxic compounds made by plants that discourage herbivores. EX- tobacco plants

– ____________(cryptic coloration)- allows organisms to

blend in EX- leaf and stick bugs

Coevolution• ____________coloration- is a conspicuous pattern or coloration

that warns predators that they sting, bite, or taste bad

• ____________- When two species resemble one another in appearance. There are two types:

– ____________mimicry- where both animals are dangerous. They share the same appearance- this is thought to teach predators through power in numbers. EX- wasps and bees

– ____________mimicry- one species is harmful, but the other is harmless and gains protection by pretending its dangerous. EX. Some species of flies have yellow and black markings to resemble bees.

Succession• ____________- change in species composition in a community over time.

____________succession occurs when a new habitat forms- such as with a volcanic island. ____________succession occurs after a natural disaster.

• Some of the changes that occur include: – ____________ species are the first species to start growing. They tolerate

intense conditions. – Substrate texture may change from solid rock to sand or to fertile soil as rock

erodes and plant and animal decomposition occurs – Soil pH may decrease due to the decomposition of materials such as leaves– Soil ability to retain water may change. – Light availability may change – Crowding may push out certain species – The final community structure that forms is called the ____________community

Energy Flow in Ecosystems• ____________Level- a level in a food chain • ________________________- autotrophs that convert light energy

into chemical energy. Include plants, photosynthetic protists, and cyanobacteria

• ________________________- herbivores- eat primary producers• ________________________- or primary carnivores- eat the

primary consumers• ________________________- eat secondary consumers• ____________- consumers that obtain their energy by eating dead

animals and plants (detritus). The smallest detritovores are called ____________and include bacteria and fungus. Others include earthworms and vultures.

Energy Flow in Ecosystems• ____________-a

linear flow of who eats whom

• ____________- many food chains put together

• As you go up a food chain- only about ____of the energy is passed along- the other 90% is used by the organism for metabolic activities.

• ____________level- a level in a food chain

Biogeochemical Cycle• Describe the flow of essential elements from the

environment to living things and then back to the environment.

• We will look at the major storage locations for each element (____________), the processes through which each element incorporates into terrestrial plants and animals (____________) and the processes through which it’s released back into the environment.

Water Cycle• Reservoirs- oceans, air (as water vapor), groundwater and glaciers. • ___________, wind and _______________move water from oceans to

land. • Plants absorb water from the soil.• Animals drink water or eat other organism and use their water. • Water is release from plants through ____________and from animals

when they sweat. Released from both when they die and decompose.

Carbon Cycle• Carbon is required for the building of all ______________ molecules • Reservoirs- _____________ (as CO2), fossil fuels (coal, oil)• Plants use CO2 for __________________• Animals ___________ plants and obtain their carbon in organic molecules• Animals breathe out the carbon in CO2• CO2 is released when anything is _____________

Nitrogen Cycle• Nitrogen is required for making all ________ acids and __________ acids

• Reservoirs- ________________ (N2) and soil

• Plants absorb nitrogen as either NO3 or NH4

• Animals obtain nitrogen by eating plants or other animals

• Animals excrete nitrogen is in their ___________

• Nitrogen is put into the soil from the atmosphere (nitrifiation, nitrogen fixation) and removed from the soil to the atmosphere

(denitrification)by ______________

Phosphorus Cycle• Phosphorus is required for the manufacture of _____ and all nucleic acids. • Reservoirs- ___________ • Plants absorb phosphorus from soils• Animals obtain phosphorus from eating plants and other animals• Plants and animals release phosphorus when they die and decompose.

• Animals excrete phosphorus is in their urine

Biomes• ______________- regions that have common environmental

characteristics• ___________ rain forests- high temperatures and heavy rainfall.

Tall trees, but little growth on the forest floor due to a lack of light. • ______________- grasslands with scattered trees. Tropical with

high temperatures, but less water than rain forests. • Temperate _______________- less water and lower temperatures

than savannas. • Temperate _____________ forests- warm summers and cold

winters where trees drop their leaves. • _______________- hot and dry. Animals and plants have

adaptations to deal with harsh conditions.

Biomes• _____________- coniferous forests. Cold winters

and precipitation in the form of snow. • __________- winters so cold the ground freezes.

During the summer, the upper topsoil thaws, but the deeper soil (called permafrost) stays frozen.

• __________ water biomes- ponds, lakes, streams, rivers

• ____________ biomes- estuaries (where rivers meet oceans), and the ocean

Biomes

Human Impact on Biosphere• Human activity damages the

environment: – _______________ effect-

the burning of fossil fuels increases carbon dioxide in the atmosphere. The increased carbon dioxide causes more heat to be trapped near the earth’s atmosphere. As a result, global temperatures are rising. This could raise sea levels by melting more ice.

Human Impacts• _________ depletion- the ozone

layer form in the upper atmosphere when UV radiation make O2 form O3 molecules (ozone). The ozone absorbs UV radiation and prevents it from reaching earth where it can damage the DNA of plants and animals. Pollutants such as CFCs (chlorofluorocarbons) have been used as refrigerants and propellents and remove O3 from the atmosphere. This has left major areas of thinning called ozone holes.

Human Impacts• ________ rain- burning fossil fuels and other industrial pollutants

contain sulfur dioxide and nitrogen dioxide. When they react with water they produce sulfuric acid and nitric acid. They return to the soil in rain or snow and can kill plants and animals.

• _________________- Overgrazing of grasslands that border deserts transform grasslands into desert.

• _________________- Clear cutting of forests causes erosion, flooding, and changes in weather patterns. The slash and burn method of clearing tropical rainforests for agriculture increases atmospheric carbon dioxide, contributing to the greenhouse effect. Because most of the nutrients in rainforests are stored in the plants, the soil is poor and can only support agriculture for a few years.

Human Impacts• ______________

_________________- some pollutants, such as the pesticide DDT or mercury, are not broken down in the environment and accumulate in the fatty tissues of organisms. As you go up in a food chain the concentration of these pollutants is higher. The biological magnification of DDT led to several species of birds, including the bald eagle, nearly going extinct.

Human Impacts• _________ Blooms- can be caused by fertilizer or sewage running off into

a lake. When the algae eventually die, bacteria break them down, and the bacterial growth depletes oxygen in the lake. The result is oxygen starvation for many animals, including fish and invertebrates. This is called ____________________.

• Reduction in __________ ______________- as a result of human activities- including habitat destruction, and hunting/poaching