biology unit 4 notes
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Chapter 4Ecosystems & Communities
• What is the difference between weather and climate?
4.1Climate
The three main zones are the polar, tropical, and temperate climates.
polar climate: the far northern and southern regions of Earth
tropical zone: surrounds the equator
temperate zone: the wide area in betweenthe polar and tropical zones
The Greenhouse Effect
• Greenhouse gasses such as carbon dioxide trap heat in the Earth’s atmosphere.
Every Organism has a habitat and Niche
A habitat is the general place in which an organism lives.
A niche describes not only the place an organisms lives, but the range of physical and biological conditions in which it lives and interacts.
4.2 Niches and Community Interactions
The Competitive Exclusion Principal
• If two species attempt to occupy the same niche, one species will be better suited to obtain limited resources and will eventually exclude the other.
What would happen if two of these warbler species tried to occupy the same niche at the same time?
Community Interactions
Predator-Prey
Herbivore-Plant
Symbiotic Species
Two or more species living together in a close, long-term association.
Parasitism – the host is harmed and the parasite benefits
Ex: lice, hookworm, roundworms
Organism benefits
0
_
Organism is harmed
Hornworm caterpillarThe host
hornworm will eventually die
as its organs are consumed
by wasp larvae.
Braconid wasp
Braconid larvae feed
on their host and release themselves
shortly before
reachingthe pupae stage of
development.
_
Parasitism
+
0
Mutualism – benefits both participating species
Ex: Clownfish and sea anemone
Commensalism – one species benefits, and the other is neither harmed nor helped
Ex: Barnacles on a blue whale
4.3 Succession
When new land is created, or a habitat is destroyed by disaster a new habitat will be created.
Succession is a regular progression of species replacement.
Primary succession occurs where life has not existed before.
Ex: A new volcanic island
Secondary succession occurs where there has been previous growth.
Ex: A forest that has been burnedUntamed science
video
4.4 BiomesBiomes are described in terms of abiotic
and biotic factors.
Tropical rain forest biomes produce lush forests.
warm temperature
abundant precipitation all year Source: World Meteorological Organization
Grassland biomes are where the primary plant life is grass.
Temperate grasslands are dry and warm during the summer; most precipitation falls as snow.
Tropical grasslands (savanna) are warm through the year, with definite dry and rainy seasons.
Desert biomes are characterized by a very arid climate.
very low amount of precipitation
four types: hot, semi-arid, coastal, and cold
Temperate forest biomes include deciduous forests and rain forests.
Temperate deciduous forests have hot summers and cold winters.
Deciduous trees are the dominant plant species.
The taiga biome is located in cooler northern climates.
boreal forest
long winters and short summers
small amount of precipitation
The tundra biome is found in the far northern latitudes with long winters.
winter lasts 10 months
limited precipitation
permafrost
4.5 Aquatic Ecosystems
• Nearly ¾ of Earth’s surface is covered with water.
• Aquatic organisms are affected primarily by water depth, temperature, flow, and amount of dissolved nutrients.
• Freshwater ecosystems include moving and standing water (wetlands, lakes and ponds, and rivers and streams).
Estuaries are dynamic environments where rivers flow into the ocean.
Mixture of fresh water with salt water
Serve as spawning and nursery grounds for many fish and shellfish
Chesapeake Bay
Louisiana bayous
Florida Everglades
Estuaries are highly productive ecosystems.
Estuaries provide a protected refuge for many species.
Estuaries are primarily threatened by land development.
Marine EcosystemIntertidal Zone
Affected by tides
Costal OceanCoral reefs and kelp forests
Open Ocean90% of oceanPhotic and Aphotic zones