Evolution/Invasive Species

Question 1

Two major claims made by evolution:

Answer 1

All living things are related and have a common ancestor
Natural Selection (natural processes change living things)

Question 2

Is there evidence supporting these claims?

Answer 2

oui

Question 3

Which branch of the evolutionary tree does the video explore?

Answer 3

Cetaceans (whales, orcas, dolphins, and porpoises)

Question 4

Give reasons why whales are not fish.

Answer 4

Embryo and mother are connected by a placenta
Live births (do not lay eggs)
Young nurse milk from mother
Warm-blooded
Fully developed lungs (no gills like fish)
Air breathers (blowhole is modified mammal nose)
Up/down tail action (dorsal/ventral undulation)

Question 5

Whales are mammals! Give examples of characteristics that whales share with land mammals. This is called comparative anatomy.

Answer 5

Hair, whiskers
Mammary glands (milk for young)
Arm, wrist, finger bones in the fin just like land mammals
Partial hind limb bones (but no hind limbs)
Nostrils on top of skull (blowhole)

Question 6

How are whale and human embryos similar?

Answer 6

Arm and leg buds present

Question 7

How does the dolphin’s blowhole form during embryological development?

Answer 7

Two nostril holes migrate to the top of the skull and fuse to form one opening

Question 8

What evidence from the fossil record of the Basilosaurid shows that whales and land mammals evolved from a common terrestrial (land-based) ancestor?

Answer 8

Nasal opening located mid-skull
Hind limb bones present (too small for walking)

Question 9

Why was Maiacetus considered to be a “walking whale”?

Answer 9

Found with sea creature fossils
Webbed hands and feet
Teeth and ear bones like the Basilosaurid

Question 10

To which land mammal are whales most closely related genetically?

Answer 10

hippo

Question 11

What are some unusual similarities between these two mammals?

Answer 11

Similar ankle bones in ancient walking whale skeletons and hippos
Hippos and whales give birth and nurse young underwater
Multi-chambered stomachs
No fur coat
Internal testicles

Question 12

Comparative anatomy, embryological studies, the fossil record, and DNA studies all support the same conclusion about whale evolution. What is this conclusion?

Answer 12

Whales evolved from four-legged land mammals.
Whales share a common ancestor with terrestrial (land-based) mammals.
Whales have changed over time (evolved).

Question 13

Native Species

Answer 13

species that evolved in a ecosystem

Question 14

Dispersal

Answer 14

the movement of organisms from one place to another (naturally or by humans)

Question 15

Exotic Species

Answer 15

species that evolved in a different ecosystem and was carried to another ecosystem by people (nonnative species)

Question 16

Invasive Species

Answer 16

species that causes ecological or economic harm in a nonnative ecosystem

Question 17

Do exotic species most often become invasive species?

Answer 17

oui

Question 18

how can dispersal occur?

Answer 18

Wind
Water
Gravity
Living things can disperse other living things (usually by accident)!

Humans may intentionally or unintentionally transport species to a nonnative ecosystem.

Question 19

What limits dispersal?

Answer 19

Physical barriers (water and mountains),

competition,

and climate can all limit dispersal.

Question 20

What about when humans disperse living things?

Answer 20

By accident and on purpose!
My Oma brought garden plants from Holland.
Seeds, insect or worm eggs, bacteria, parasites or pathogens, and “stowaways” can all travel with humans by accident
The organisms dispersed by people are called exotic species.
Exotic species can harm native species populations.

Question 21

Competition Affects Populations…

Answer 21

…and competition is a natural, normal part of ecosystems, but sometimes competition is caused by humans and the native species may not have a fighting chance.
Exotic species are introduced by humans and often become invasive species!