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Animal Population. Diversity and Structure. Species diversity – number of different species a community contains combined with the abundance of individuals within those species. Community niche structure – how ecological niches vary and differ. Niche – a species role in the community
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Diversity and Structure • Species diversity – number of different species a community contains combined with the abundance of individuals within those species. • Community niche structure – how ecological niches vary and differ. • Niche – a species role in the community • Most diverse or species rich environments are the tropical rain forests and some coral reefs.
Species types • Native Species – normally live in and thrive in a particularly area • White Tailed Deer, Bald Eagle, Opossum • Nonnative Species – accidentally or deliberately introduced to an area • Horses • Invasive Species/Alien Species – wreak havoc on the environment. No natural predators
Invasive Species • Asian Carp • Mississippi River • No natural predators • Eats all the plankton • Kudzu Vine • South United States • 7 million acres • Grows 1 ft per day • Kudzu bug (also invasive) started eating all of the soybean crop.
4. Indicator Species – a species that serves as early warnings of danger to an area Ex – Butterflies, trout, frogs Butterflies- They have brief life cycles and are affected by climate change and pesticides. Birds plan their breeding season around when the caterpillers are most abundant Trout- Healthy stream=abundant trout They need clean water, a specific temperature, protection, unsilted gravel to spawn and an abundant food supply.
Indicator Species • What about the frogs? Well… • Vulnerable because different life cycles involve different habitats • Tadpoles – live in water and eat plants • Adults – live on land and eat insects that can be exposed to pesticides • Eggs – have no protective shell so are vulnerable to increased UV rays or pollution
Hundreds of species have vanished since 1980 • ¼ of all amphibian species are extinct, endangered or vulnerable Why should we care? • Their death indicates that there is some deterioration of the environment • Large part of the ecological pyramid – they are predator and prey • Secretions in the skin - Can be used in the pharmaceutical industry for medication
5. Keystone Species – species that have a significant role in the community Examples: A.Pollinators such as bees, humming birds, bats B. Top predators such as wolves, lions, alligators, and sharks C. Decomposers such as beetles • A loss of these types of species leads to population crashes and extinctions
6. Foundation species – species that shape communities by creating and enhancing their habitats in ways that benefit others Ex – Elephants, beavers
Energy in an Ecosystem • Energy is the most important factor in determining how many and what kinds of organisms live in an ecosystem.
Trophic Levels 1st Level • Producers: take in energy from their surroundings and store it in complex molecules. • Also called autotrophs/ photosynthetic • Use the sun to power the production of food.
2nd Level • Primary Consumers • Obtain energy by consuming Autotrophs. • Also called heterotrophs.
3rd Level • Secondary consumers • Obtain energy by consuming both producers and primary consumers
Tertiary Level • Apex predators • Top of the food chain • Will consume anything from all of the previous levels
Decomposers • Consumers that obtain energy by consuming organic wastes (feces, urine, leaves, dead plants) and dead bodies. • Recyclers of nutrients.
Food Chain • Single pathway of feeding relationships among organisms in an ecosystem that results in energy transfer. • Example: grass mice snake hawk
Food Web • Multiple food chains in a ecosystem • Many consumers eat more than one kind of food. • More than one species may eat the same organism.
Species interaction 5 Basic types of interaction 1. Interspecific competition – competition between species for shared resources such as space and food 2. Predation – one species (predator) directly feeds on another (prey) Ex – lions eat gazelle 3. Parasitism - when one species (parasite) feeds on part of another organism (host) Ex – Ticks, Tapeworm
4. Mutualism – two species interact in a way that benefits both.Ex – Oxpeckers and Rhinos Clown fish and sea anemones
5. Commensalism – one species benefits and the other is not effectedEx – Epiphytes and tropical treesRemora Fish and the Shark
Avoiding Predation 1. Camouflage – uses shape or color to hide
2. Chemical warfare – examples are poisons, irritants (stingers), Foul smells (skunk), tasting bad (monarch butterfly)
3. Warning colors – bright colors indicate an organism is poisonous
Limits on Population Growth • Environmental resistance – factors that act to limit the growth of a population • Examples: disease, predators, natural events, humans • Logistic growth – involves exponential growth followed by a steady decrease in population growth with time until the population size levels off.
Human Impacts We Have: • Reduced biodiversity • Used, wasted, or destroyed net primary productivity that supports all consumers • Strengthened some populations of pests and bacteria • Eliminated some predators • Introduced nonnative species in communities • Interfere with chemical cycles and energy flow