Unit 8: Biodiversity Study Guide

Introduction

• For most ecosystems, the ultimate source of energy is the sun

  • However, not all ecosystems absorb the same amount of energy

    • The amount of energy absorbed (amount of photosynthesis being done) in an ecosystem is referred to as primary production

• Vegetation refers to the number of plants on land

  • A higher (darker) vegetation index generally indicates a higher rate of photosynthesis

• Chlorophyll is the name of the green pigment that plants use to make food during photosynthesis

  • A higher chlorophyll concentration generally leads to a higher rate of photosynthesis

• A higher biodiversity leads to greater overall productivity

Formation of Biomes

• The amount of water available and the temperature in a biome determine what type and abundance of plants can grow (depends on latitude and altitude)

  • More sunlight = More productivity

  • More productivity = More biodiversity

Biomes and Climate

• Earth’s tilted axis causes seasons as it revolves around the sun

• Weather: Day-to-day conditions at a particular place and time

• Climate: Average, year-after-year conditions in a region

• There are 3 main climate zones

  1. Polar = Cold areas

  2. Temperate = Hot/cold seasons

  3. Tropical = Always warm

Tropical Rainforest

• Has the most species (biodiversity)

• Canopy = Top

• Understory = Below the canopy

• Hot and wet year-round; poor soil

• Arboreal = an animal that lives in trees

• Brachiation = movement by swinging

Savanna (Tropical Grassland)

• Grassland area, with a few trees

• large animal herds and frequent fires

• Lions, Sebra, Wildebeest, Gazelles, Elephants, Giraffes

Desert

• Dry (less than 25 cm of rainfall each year)

• Extreme temperature changes (hot/cold)

• Cacti/succulent plants

• Organisms able to tolerate extreme conditions

Temperate Grassland (Plains and Prairies)

• Midwest, very fertile soil

• 4 seasons: Seasonal precipitation

• Deer, Prairie dogs, Coyotes, Songbirds, Raptors, Snakes

Chaparral

• Dominated by shrubs, frequent fires

• Example: Los Angeles, CA

Temperate Deciduous Forest (Eastern portion of US)

• Deciduous trees, 4 seasons

• Seasonal rainfall

• Trees: Maple, elm, oak, pine

• Animals: squirrel, songbirds, rabbits, owls, snakes, reptiles, raptors, rodents

Boreal Forest (Taiga)

• Evergreen forests

• Cold, long winters

• Short, mild summers

• Known as the coniferous forest in the US

Tundra

• Permafrost = layer of permanently frozen subsoil

• Strong winds: no trees, small plants

• Plants = mosses, lichens, grasses

• Animals = Arctic fox, Caribou

Freshwater

• Flowing: water ecosystem, rivers, streams, creeks

• Standing: water ecosystem, lakes, ponds

• Trout, herons, eagles, bass, bluegill, crayfish, water snakes, turtles

• Estuary = where freshwater meets sea

• Wetlands = water covers soil (marshes and swamps)

Marine

• Photic zone: area sunlight reaches

• Aphotic zone: permanently dark

• Plankton: microscopic organisms found in water

• Sharks, whales, dolphins, fish, anemones, squid, seagulls, pelicans, crabs, shrimp

What is Biodiversity?

• Biodiversity is the number and variety of different species in an ecosystem

• First coined by Walter G. Rosen in 1985, biological diversity (biodiversity) is defined as the variety of life on Earth and the natural patterns it forms

  • All organisms within an ecosystem are interconnected

  • When the diversity of organisms within an ecosystem declines, so does the ecosystem’s ability to function and survive

• Ecosystems with higher primary productivity tend to have higher biodiversity

  • More energy is available to support a variety of organisms

• Biodiversity increases near the equator for 3 reasons

  1. More sunlight

  2. Consistent temperature

  3. Old (unchanging) environment

• Ecosystems with higher biodiversity are better able to recover after environmental change

  • Diversity can happen at many levels

Species Richness vs. Species Diversity

1. Species Richness: total number of different species

2. Species Diversity: relative abundance of the different species (evenness)

• Both communities are equally rich, but Community 1 is more diverse

  • Community 1 would be more likely to survive a forest fire because it is more diverse and can repopulate all species

Monitoring Biodiversity

Random Sampling

• Technique involving plants where samples are chosen from a population by using a random number table or a random number generator

• Steps to Random Sampling

  1. Count 10 random squares (could be any number)

  2. Find the total number of flowers counted (doesn’t have to be flowers)

  3. Find the Average per square by dividing the total by the number of random squares

  4. Multiply the average by the total number of squares to find the approximate number of plants in the whole area

Mark and Recapture

• Technique involving animals where a portion of the population is captured, marked, released, and recaptured

Succession

• Ecological succession is the process by which natural communities replace (succeed) one another over time

• There are two types of succession

  1. Primary

  2. Secondary

• Pioneer species are the first species to inhabit an area

• Clmax Community is when the species replacement slows and the ecosystem stabilizes

Primary Succession

• Occurs when there is new soil formation

• Establishes a New Community where no life has been

• Example: volcanic island

Secondary Succession

• Occurs after ecosystem disturbance (forest fire, floods, farming, etc)

• Starting over, but not from scratch

Species Interactions

• Coevolution: Two species evolve in response to changes in each other

• A symbiotic relationship is an intimate relationship between two or more species (not always positive)

  1. Mutualism: biological interaction between 2 species where both benefit from each other

     • Example: Flowers and Pollinators

  2. Commensalism: One benefits, the other is neither harmed nor benefited

     • Example: Whales and Barnacles

  3. Parasitism: Feeding off of another organism (not intended to kill the host)

     • Example: Tapeworm in intestine

  4. Predation: Killing and eating another organism

     • Example: A Cheetah hunting a Gazelle

Adaptations of Parasites

• Parasites are adapted so that they receive maximum benefit from the host, but do not kill them

  1. Suckers and hooks for attachment

  2. Thick, resistant outer coverings

  3. Anaerobic (if living inside the digestive tract)

Predator Adaptations

• Teeth, claws, vision, strength, camouflage, and working together

• Mimicry: One species resembles another as defense

• Warning (Aposematic) Coloration: Conspicuous markings or bright colors possessed by an animal that serve as a warning to potential predators that it is toxic or distasteful

• Individual Defense Mechanisms: How one individual stands up for themselves

  1. Startle Behavior (blowfish)

  2. Anatomical Defense (Porcupine)

  3. Chemical Defense (Skunk)

Group Defense Mechanisms

• Pack behavior, herding behavior (zebra), schooling fish, swarming insects