biodiversity module 1

Adaptation

A process that occurs to allow organisms to survive in their changing environments.

Human-induced____________ by the increase in________ in the atmosphere is the greatest threat to biodiversity.

- climate change - greenhouse gases

The_____________ indicates that species have become extinct throughout the history of life.

- fossil record

mass extinction

- global event that wipes out the majority of living organisms on earth - occurs very rapidly - over 50% of the species on planet earth are wiped out after the event

If the rate of species loss is_________the rate of speciation, then there is a general________of biodiversity.

- higher than - loss

Species are identified by a two-part Latin name

such as Homo sapiens (humans) or Panthera orca (jaguar).

Taxonomy

the identification and naming of species.

Currently there are____known species

2.2 million

Which of the following terms best describes the relationships among an organism, species, and population?

Populations are groups of organisms of the same species living in the same geographic area.

Currently, there are approximately 8.7 million species that have been identified and described.

false

The total number of species on the planet is an estimated calculation offered by scientists.

true

The loss of many species is_______and occurs no matter how well adapted those species were before the event.

global

The first mass extinction occurred at the end of the_________period. The ___________ at this time would have been dominated by invertebrates and early vertebrates. After the extinction event, over 50 percent of marine species went extinct but made way for the first ________fishes.

- Ordovician - sea animals - jawed

population

A group of individuals that belong to the same species and live in the same area

species

a group of similar organisms that are reproductively compatible and capable of interbreeding and producing living offspring.

organism

an individual of one species

Over time, a species may not be able to adapt to a change in its climate, habitat, or food source, and may naturally go

extinct

biodiversity hotspots

Relatively small areas of land that contain an exceptional number of endemic species and are at high risk from human activities cover only 2.4% of the world's surface, but they account for over 50% of all plant and 42% of all animal species.

According to the biological species concept, what determines if two organisms are different species?

They are reproductively isolated from each other.

phylogenetic species concept

Traces the organism's evolutionary history and its relatedness to other species through its traits. In this model, studying an organism's traits and location on the evolutionary tree is a better indication of whether it is a unique species than the biological species concept.

If you include bacteria and viruses, recent studies have indicated a realistic estimation of total biodiversity is up to 100 million species.

false

In some instances, impact events, such as an asteroid impact, or rapid changes in the environment do not leave organisms time to adapt and leads to loss of many species very rapidly, called

mass extinctions

Biodiversity

refers to not only the total number of a species in an area, but also how many different species are found in that area.

The biological species concept uses ______________ to designate separate species.

reproductive isolation

morphological species concept

separates species based on differences in physical traits, or morphology (morph- means "form"). This is useful for studying the fossil record where you can't determine reproductive isolation. It is difficult to apply to organisms that do not leave fossil records.

The process of speciation is generally a very_______process, often taking millions of years to occur completely.

slow

The rate of speciation and the rate of________shapes the patterns of diversity on planet Earth.

species loss

biological speices concept

the most used method since it defines a species as being one that is reproductively isolated from other species. This model only works if a species reproduces sexually and is currently alive.

specation

the ultimate source of species diversity and occurs over time as organisms respond to changes in the environment.

Of the described species, approximately 391,000 species are plants, 140,000 are fungi, and 1.5 million species are animals.

true

Scientists generally agree that many more species exist than are formally described, but they disagree about how many there really are.

true

The fifth mass extinction,__________ extinction, occurred about 65 MYA. This extinction eliminated all___________ and many reptiles and allowed for the rise of mammals.

- Cretaceous - dinosaurs

Approximately 360 MYA, at the end of the_______period, the second mass extinction wiped out 50% percent of animal species on land and in seas. Shortly after the extinction event, the______________, such as insects, amphibians, and early reptiles, appeared.

- Devonian - terrestrial animals

The fourth mass extinction occurred about 200 MYA at the end of the_______period. This extinction eliminated_______percent of all existing animal species including reptiles, early dinosaurs, and the first mammals. After the extinction event, angiosperms spread and modern_______ appeared.

- Triassic - 48% - insects

gradualistic model

- a population accumulates tiny variations slowly and gradually until reproductive isolation occurs - ideas were supported by Charles Darwin - over time, small variations such as longer teeth, and a heightened sense of smell became the normal characteristics of a wolf population

punctuated equilibrium model

- a sudden event results in speciation followed by long periods of no change - typically observed in fossil record - climate change causes the spoil pH to change rapidly and many of the worms die, leaving only those able to adapt and survive in the new ph to reproduce

The record that has been left behind and used to describe the evolution of life has noted several sudden and global extinction events, known as__________ These events tend to not only mark the boundaries of_____________but also usually represent significant shifts in the evolution of life.

- mass extinction -geological time periods

background extinction

- natural on going low level extinction of species - due to changes in various environmental factors that reduces a species ability to cope to the change - does not typically result in a large loss of species - between 0.1 and 2.0 species is lost per million species per year

The mass extinction at the end of the________ period (about 250 MYA) is thought to have killed off as many as________ percent of the animal species. The first _____and dinosaurs appeared.

- permian - 83% - mammals

Today, the rate of___________is comparable to those periods of mass extinctions, and_________are considered the driving force behind the current biodiversity crisis.

- species loss - human activities