1 Chapter 24: Interactions of Life Sect. 1: Living Earth

2 The Biosphere Biosphere – the part of the Earth that supports life. a. top part - Earth’s crust b. water – oceans, rivers, lakes, streams, etc. c. atmosphere d. non-living (abiotic) & living (biotic) organisms

3 Biosphere The biosphere contains he amount of energy that reaches the Earth from the Sun is just right for life. However, it is a fixed amount of water/ carbon/ nitrogen/oxygen/ and other minerals

4 Biosphere made up of different environments (largest group to smallest) Biosphere -Earth’s surface & atmosphere Ecosystem - water/whales/shrimp Community- whales & shrimp Population - two or more whales Organism – one whale

5 Ecosystems Ecosystem - all the organisms in the area and the nonliving parts of that environment. Ecology – study of interactions among organisms and their environments. Ecologist – scientists who study these interactions

6 Populations A population is made of all the organisms of the same (one) species that live together in an area at the same time. Ex: all the bison in a prairie ecosystem are a population of bison Community – all the populations of all species living in an ecosystem ** ONLY BIOTIC –no abiotic factor

7 Community Community – all the populations of all species living in an ecosystem Ex: A prairie community is made up of bison, grasshoppers, cowbirds, and all other species. ** ONLY BIOTIC –no abiotic factor

8 Habitats The place in which an organism lives is called its habitat. An organism’s habitat provides food, shelter, proper temperature and moisture that the animal needs to survive. Ex: The burrow a chipmunk digs under a patio

9 Section 2: Populations factors that affect populations Competition for Food and Space a. Organisms living in the wild do not always have enough food or living space. b. Ex: Woodpeckers must compete for nesting spots.

10 Growth Limits Competition limits population size - sampling. The most intense competition is usually among individuals of the same species.

11 Populations factors that affect populations Population Size The number of individuals of one species per a specific area is called population density.

12 Measuring Populations 1. counting by trap-mark-release method 2. counting using sample counts –Count the number in a given area & then multiply that number by the area.

13 Trap-mark - release Ecologists set traps to capture the animal. They are marked and released. Another sample is captured and the ecologist compares the number of marked animals to the number of unmarked animals.

14 sample counts To estimate for a large area, take a count of the animals in a small part of the area, then multiply by the whole area. –Ex. To estimate the number of rabbits in 100 acres. –Count the number in 1 acre and multiply that number by 100.

15 factors that affect populations Limiting factors anything that restricts the number of individuals in a population. Availability of food, water, living space, mates, nesting sites, and other resources limit populations. Ex: lack of rain

16 Carrying capacity –largest number of individuals of one species that an ecosystem can support over time.

17 Biotic Potential Biotic Potential – the highest rate of reproduction under ideal conditions

18 Changes in Populations Birth rates and death rates – When number of deaths is greater than number of births, populations get smaller. Moving around- immigration/emigration Exponential growth – when a population grows quickly – the larger it gets, the faster it grows

19 SECTION 3 Interactions within Communities Obtaining Energy 1. The energy that fuels most life on Earth comes from the Sun. 2. The energy-rich molecules, usually sugars, serve as food. Food gets converted to chemical energy Energy is stored in the chemical bonds that hold atoms together.

20 Producers Producers – organisms that use an outside energy source like the Sun to make energy-rich molecules. (Make own food) – Autotroph most contain chlorophyll

21 Photosynthetic Producers photosynthesis – process that uses an outside energy source like the sun to make energy rich molecules (food). Ex. Green Plants

22 Photosynthetic Organisms beyond plants Phytoplankton Blue Green Algae

23 Chemosynthetic Producers chemosynthesis – use inorganic molecules in the water to make food. Most live near volcanic vents on the ocean floor EX. types of bacteria or methogens

24 Chemosynthetic Bacteria

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26 Consumers - Heterotrophs Consumers – organisms that cannot make their own energy-rich molecules. It must consume other organisms for food.

27 Types of Consumers herbivores- plant eater (rabbit) carnivores- meat eater, (tiger) omnivores- plant or meat (humans) decomposers-consume dead organisms (fungi/bacteria/earthworms)

28 Food Chains Food Chains – simple model of the feeding relationships among the organisms in an ecosystem Lowest level – producer which gets eaten by consumers a. The arrows in the chain point in the direction of the energy flow producer towards consumer

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30 Symbiosis Symbiosis – any close relationship between species »a. Mutualism »b. Commensalism »c. Parasitism

31 mutualism mutualism – both species benefit –Ex: Lichens (alga or cyanobacterium & fungus) (small fish cleaning a larger fish)

32 Mutualism both benefit

33 Commensalism Commensalism – one organism benefits and the other is not affected Ex: clown fish living inside a sea anemone

34 Commensalism one benefits – other not harmed nor does it benefit

35 Parasitism/ Predator Prey parasitism – one organism benefits but the other is harmed usually doesn’t kill the host. –Parasite- host –Ex: a tick/human –Spanish moss/tree predator and prey relationship – one organism benefits at the expense of the other organism – (hawk eats a snake) one lives/one dies

36 Parasitism one benefits – one is harmed

37 Predator Prey

38 Niche Niche – an animal’s role/how it survives in its environment How it obtains food and shelter, finds a mate, cares for its young, avoids danger an organism’s niche includes how it avoids being eaten and how it finds or captures its food.

39 cooperation cooperation – animals sometimes work together in their niche