Biology I - Comp 3 Review
Organisms and Their Environments
Name: ___________________________________
Introduction to Ecology
 _______________________is the study of organisms and their interactions with their environment.
 The environment includes 2 types of factors:
 __________________ factors – the living parts of the environment
 Plants, animals, bacteria, fungi, etc
 ___________________ factors – the nonliving parts of the environment
 Water, oxygen, light, temperature, etc.
Nutrient Cycles
 Some abiotic factors are ____________________ that are needed by plants and animals to survive.
 These nutrients are _________________ through the ecosystem.
 Helps maintain ___________________________, or balance, within the environment.
 The 3 main nutrient cycles are:
 ___________________
 ___________________
 Nitrogen
Water Cycle
 _____________________________ – water changing from a liquid to a gas
 Transpiration – water evaporating from the leaves of plants
 _____________________________ – water changing from a gas to a liquid
 Precipitation – water returning to the land in the form of rain, sleet, hail, or snow
Carbon Cycle
 _____________________________ and Cellular Respiration cycle carbon and oxygen through the environment
 Photosynthesis uses CO2 and produces O2
 Respiration uses O2 and produces CO2
 Carbon may be returned to the soil through _______________________________
 Carbon may also returned to the atmosphere through ___________________ activity and burning
__________________________________
Nitrogen Cycle
 Most Nitrogen is found in the atmosphere, but organisms can’t use it in that form
 Atmospheric Nitrogen is made usable for living things through _____________________________________
 Nitrogen-fixing __________________________ on the roots of some plants
 Lightning strikes
 _______________________________ – other bacteria in the soil can convert “fixed” nitrogen back into Nitrogen gas
(N2)
 _____________________________ – Plants use Nitrogen in the soil to form amino acids and other organic
compounds
 Consumers obtain Nitrogen from eating producers
 When plants and consumers die, __________________________ return the Nitrogen to the soil
Levels of Organization
 _________________________ –
 Any unicellular or multicellular form that exhibits all the characteristics of life
 An individual
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 Example: A zebra
____________________________ –
 A group of organisms of the same species that live together in a certain area
 Interbreed and compete for resources
 Example: A herd of zebras
_____________________________ –
 Groups of organisms of different species that live together in a certain area
 Example: A herd of zebras, a pride of lions, & a pack of hyenas
_____________________________ –
 All the living and nonliving things in a certain area
 Communities and the abiotic factors with which they interact
 Example: Zebras, lions, hyenas, rocks, air, water, etc.
____________________________  a group of ecosystems that have similar climates and communities
 Example: Savanna
____________________________  the entire portion of the planet that supports life
Biomes
 ___________________________
 ___________________________
 Tundra
 Taiga
 Tropical Forest
 Savanna
 Chaparral
 Desert
 Temperate Grassland
 Temperate Deciduous Forest
 Tundra
 _________________
 Little precipitation: 15-25 cm/year
 Average winter temp. -30 degrees C
 Summer < 10 degrees C
 Long winter; very short summer
 ___________________________ – almost permanently frozen snow/ice
 Small plants with _____________________________, a few DWARF shrubs
 Migratory animals or animals with High tolerance for very ___________________ conditions
 Adaptations: Animals may have ___________________________for camouflage. Plants have short roots
because of permafrost.
 Taiga (Northern Coniferous Forest)
 Seasonal rainfall: 30-80 cm; some much more
 Winters -50 degrees C in winter
 Summer 20 degrees C
 __________________________________; short summer
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 Plants: ___________________________________ trees, diverse shrubs, lichens & mosses
 Animals: _________________________ animals, large herbivores & predatory animals
 Adaptations: Plants with ________________ needles to help retain water. Animals may
____________________________ during coldest months
Tropical Rain Forest
 Seasonal rainfall: 200-400 cm/yr
 25-29 degrees C year round
 Located along the _______________________
 Summer year round
 Most __________________ species of plants & animals
 Plants: Broad leaves, vines, orchids, bromeliads. Soil lacks _____________________
 Animals: Lots of insects and tree dwellers
 Adaptations: Many forms of camoflauge, ______________________________, diet heavy on fruits
Savanna
 Seasonal rainfall; 50-120 cm/yr, with a long drought season
 Temperature: 20-30 degrees C (warm!)
 Distinct _________________________________ seasons
 Frequent __________________ during dry season
 Plants: Tall _____________________, scattered small trees and shrubs
 Animals: Lots of herbivores (grazers), and carnivores (hunters)
 Adaptations: ____________________ tolerant & fire-resistant
Desert
 Rainfall < 25 cm/yr (arid/dry)
 Hot deserts > 50 degrees C
 Cold deserts (Antarctica) <-30 degrees C
 ________________________ changes in temperature
 Ex: Very hot during the day & cold at night
 Plants: Cacti, creosote bushes, _________________________
 Animals: small _________________________ carnivores, reptiles, birds & insects
 Adaptations: Plants with __________________________________and thick leaves to obtain and hold water.
Reptiles with thick, _______________________ skin to hold water. Many nocturnal animals.
Temperate Grassland
 Dry winters, wet summers: 30-100 cm/yr.; seasonal _____________________
 Cold winters < -10 degrees C; Hot summers 30 degrees C
 Seasonal drought & periodic ________________
 Dark ______________________________
 Plants: Lush grasses & ____________________________
 Animals: Large herbivores & predators, burrowing mammals
 Adaptations: Drought & _____________________________ plants.
Temperate Deciduous Forest
 Rainfall: 75-150 cm/yr
 Cold Winters & hot summers. 0-35 degrees C
 4 _____________________________________
 Our biome!
 Plants: ___________________________ & coniferous trees, shrubs, mosses, ferns
 Animals: variety of mammals, birds, insects
 Adaptations: Deciduous trees _______________ their leaves in winter to keep from freezing. Some
migratory animals & birds.
Types of Interactions Between Organisms
 ______________________________ – when resources are scarce, only some organisms will survive
 Food Chains & Webs – diagrams showing the feeding relationships in an ecosystem
 Predator/Prey Relationship – some animals hunt others for food
 _______________________ Relationship – close interaction between two or more organisms of different species
Competition
 When resources are limited, competition for those resources results.
 ______________________________ competion – between organisms of the same species
 ______________________________ competition – between organisms of different species
 ____________________________________ – any biotic or abiotic resource that limits the growth of an organism
or population in a specific environment
 Availability of water
 Availability of food
 Availability of habitat
 Temperature
 Density_________________________ Limiting Factors – depend on the number of organisms in a population
 Food, Water, Predation, Disease
 Density _____________________________ Limiting Factors – do Not depend on the number of organisms in a
population
 Weather, Natural Disasters, Human Activities
 _______________________ – the place where an organism lives
 _______________________ – the role an organism plays in its environment
 If two organisms occupy the same niche they will compete for resources until one species is forced out
Food Chains & Webs
 Producers (____________________________) – Produce their own food through Photosynthesis or
Chemosynthesis
 Ex: Plants, algae
 Consumers (____________________________) – Must consume other organisms for food & energy
 Types of Consumers
 _________________________ – Primary consumers
 Eat Plants
 _________________________ – Secondary & higher consumers
 Eat other animals
 _________________________
 Eat both plants and animals
 ____________________________ – Feed on organic waste (dead plants and animals)
 Ex: Earthworms
 ____________________________ – Breakdown dead plants & animals into simpler molecules that can be
absorbed
 Ex: Bacteria, Fungi
 The arrows in a food chain/web show the __________________________________ from one organism to the next
 Only __________ of the available energy is transferred from one trophic level to the next. The rest is lost
as heat.
 The ______________________________ of an organism is the position it holds in a food chain/web/pyramid
 (Primary, Secondary, Tertiary, etc.)
 ____________________________ – a linear representation of energy transfer between organisms
 ____________________________ – a network of interconnected food chains in an ecosystem
 Food Pyramids
 Pyramid of ___________________ – Shows the amount of energy available at each trophic level
 ______________________ Pyramid – Shows the amount of biomass at each trophic level
 Pyramid of ____________________ – Shows the number of individual organisms at each trophic level
Predator/Prey Relationships
 _____________________ populations can control the size of ____________ populations, and vice versa.
 The _______________________________ in an ecosystem has no natural predators.
Symbiotic Relationships
 ________________________ – two organisms of different species living closely together.
 There are 3 types of Symbiosis
 __________________________ – Both species benefit
 ___________________________________ – One species benefits and the other is not affected
 __________________________ – One species benefits and the other is harmed (parasite & host)
Biological Magnification
 Chemicals or _____________ may be introduced into an ecosystem through human actions.
 As they move up through a food chain, they have a more _________________ affect on each higher trophic
level.
 Ex: DDT
Ecological Succession
 Ecological Succession – the predictable and orderly changes in the composition or structure of an
ecological community over time.
 _____________________________________ – the first species to populate an area
 _______________________________________________ – the final community of organisms in an ecosystem
once it becomes stable
 ______________________ Succession – occurs on surfaces where no soil exists
 Ex: Volcanic rock surfaces after an eruption
 ____________________________ Succession – occurs on pre-existing soil
 Ex: A forrest after being burned or cleared for construction
Human Impact on Ecosystems
 ___________________________ is the variety of life in an ecosystem
 It may be decreased by human activities such as:
 Use of pesticides and chemical fertilizers
 ______________________________ and clearing land for construction
 Introducing ___________________________ species
 Exploitation of wildlife
Biological Magnification
Carbon Cycle
Nitrogen Cycle