Ecology: Part 1 Mrs. Bradbury

Ecology: Part 1 Mrs. Bradbury

Biotic and Abiotic Factors All environments include living and non-living things, that affect the organisms that live there. Biotic Factors all the living organisms in an environment Ex: plants and animals Abiotic Factors all the non-living parts of the environment Often determine which species can survive in an environment Ex: air, water, soil, temp., currents, wind, etc

What are some of the biotic and abiotic factors in this picture?

Populations A group of organisms of the same species living in the same place at the same time that can interbreed. SAME SPECIES INTERACTIONS Compete for food, water, minerals, resources, and mates Resources determine: How large populations can become How far apart populations are All of a population must use the same resources causes competition.

Communities Collection of interacting populations DIFFERENT SPECIES INTERACTIONS Must live within the same environment Ex: Sharks and Seals A change in a population of one species in the community will cause change to the other populations in that community.

Ecosystems Interactions among populations in a community and the communities physical surroundings or abiotic factors. Two Types: Terrestrial Ecosystems land Ex: Forest or meadow Aquatic Ecosystems Fresh or saltwater Ex: pond or salt marsh Within an ecosystem every species has a particular job. Helps maintain the homeostasis (balance) of the community.

Niche and Habitat Niche the role/job of a species in a community Includes food, space, conditions an organism needs to survive and reproduce Ex: Coyotes keep rodent # s down in grasslands. Habitat where an organism lives out its life. Can be shared by several different species Niche reduces competition within a habitat Will feed on different materials, different ways, at different times. (arctic habitat) (decomposers recycle nutrients)

Changes in Populations Populations of organisms do NOT experience linear growth (growth in a straight line) Usually a growing population starts out slowly, than begins to resemble a J-shaped curve. This is called Exponential Growth

Exponential Growth Starting growth is slow because the number of reproducing adults is small. When the # of reproducing adults increases, the growth rate increases. Exponential Growth as a population gets larger, it also grows at a faster rate. This type of growth will continue as long as unlimited resources are available.

Carrying Capacity In reality growth is always limited. Ex: Availability of food, disease, predators, or lack of space limits population growth. Under these pressures the population growth will stabilize (level off) and form an S-shaped curve. Population growth will stabilize at the Carrying Capacity of the ecosystem. Carrying Capacity (K) the number of organisms an environment can support and still maintain homeostasis.

Factors Affecting Population Growth 1. Birth Rate When births exceed deaths, the population increases. Will continue to increase until the carrying capacity is reached or passed. Population has unlimited resources and there is a lack of competition. 2. Death Rate When deaths exceed births the population will decrease. Causes population to drop below the carrying capacity Limiting factors such as lack of resources, disease, or increased predation may cause an increase in deaths.

Factors Affecting Population Growth Continued 3. Immigration organisms from one population move into another population s habitat. Causes an increase in the population More possible mates but also increases competition for resources 4. Emigration organisms leave a population Causes a decrease in the population Could be due to lack of habitat or other resources.

How Organisms Interact Species relationships are needed for: 1. Obtaining energy and material necessary for life. 2. Help maintain a balance within populations, communities, and ecosystems. (Preserves homeostasis)

Organisms Niches 1. Autotrophs use energy from the sun or energy stored in chemical compounds to manufacture their own food PRODUCERS! Two Types: a. Photosynthesizers use CO2, water, and sunlight to make sugars (energy). Ex: Plants b. Chemosynthesizers use chemical compounds to produce energy. Ex: Bacteria that live in deep ocean vents * All other organisms depend on autotrophs for nutrients and energy!

Organisms Niches Continued 2. Heterotrophs organisms that depend on autotrophs Consumers! Four Types: a. Herbivores feeds directly and only on plants. (Ex: grazing animals) b. Carnivores Kills and eats other animals. (Ex: Lions and wolves) c. Scavengers Feeds animals that have already died. (Ex: vultures) d. Omnivores Feeds on both plants and animals. (Ex: bears and humans)

Organisms Niches Continued 3. Decomposers breakdown and absorb nutrients from dead organisms. Very important to the health and homeostasis of the community. Recycle nutrients Ex: mushrooms, fungal bacteria, protozoans

Survival and Symbiosis Biologist assume that all organisms in the same environment are in a continuous battle for survival. Sometimes different species will form relationships with other species to aid in their survival. This is called symbiosis. Symbiosis living together relationship in which there is a close permanent association between organisms of different species.

Types of Symbiosis 1. Mutualism Both species benefit Ex: Crocodiles and Birds the bird cleans the crocs. teeth and the bird will get a meal and the croc. clean teeth.

Types of Symbiosis Cont 2. Commensalism One species benefits and the other is neither harmed nor benefited. Ex: Trees and Moss Trees will provide a nice habitat for the moss and the moss neither hurts nor helps the tree.

Types of Symbiosis Cont 3. Parasitism One organism benefits at the expense of another. May harm but does not kill the host. Ex: Ring worm and animals. Fungal infection that makes animals have an itchy rash.

Non-symbiotic Relationship Predator Prey (Predation) One species is killed and one species benefits Ex: Lion and Zebra